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Fluoride debate: A response to Rita Barnett-Rose – Daniel Ryan

Dan Ryan 2

Daniel Ryan from the Making Sense of Fluoride group

Daniel Ryan President of the Making Sense of Fluoride group responded to the scientific claims made in Rita Barnett-Rose’s unpublished paper Compulsory water fluoridation: Justifiable public health benefit or human experimental research without informed consent“.

That section of Rita’s paper was posted as the first article in this exchange yesterday at Fluoride debate: The scientific evidence against fluoridation – Rita F. Barnett.

Daniel’s critique is available to download as a pdf.

Compulsory water fluoridation: A response to Rita Barnett-Rose – Daniel Ryan


I have contacted Associate Professor Rita Barnett-Rose about her unpublished paper Compulsory water fluoridation: justifiable public health benefit or human experimental research without informed consent.”  It concluded that “The evidence continues to suggest that compulsory water fluoridation is no longer justifiable as a public health benefit” and “human rights burden and economic costs are not reasonable or justifiable”.

There were claims about the science which (presumably) are important for the legal/ethical conclusions. We at Making Sense of Fluoride (MSoF) felt there was misinformation on the science and a public exchange would be a good way to engage in a discussion of the claims – even withdrawing those claims if found wrong. We thank Rita for listening to us and hope that we find common ground even if it’s just in the science.


For the most part of this discussion I will stick to pages 13-19 with the header “Scientific Evidence against Compulsory Water Fluoridation” and breaking down into the sub-headers.

First off, looking at the sources used, there are many that are comments and articles from political activists rather than primary research sources. For example Fluoride Action Network is not a credible scientific organisation. This is not a good way of reviewing the scientific literature; in fact it is very poor practice. This is a fundamental problem with this paper.

The paper starts off saying there is mounting scientific evidence against fluoridation. The evidence used was an opinion piece from John Colquhoun. Dental Watch has a paper “Why We Have Not Changed Our Minds about the Safety and Efficacy of Water Fluoridation: A Response to John Colquhoun” that critiques his paper:

“His paper rehashed earlier criticisms of water fluoridation, using selective and highly biased citations of the scientific and non-scientific literature”.

Why I Am Now Officially Opposed to Adding Fluoride to Drinking Water” from Dr. Hardy Limeback and “Dr. William Hirzy Portland letter” are also opinion pieces. It is important to note that Dr. Hardy Limeback is a member of the Advisory Board of Paul Connett’s Fluoride Alert Network. Dr. William Hirzy works for Fluoride Action Network as a paid political lobbyist. “Mounting scientific evidence”– nothing could be further from the truth. There is not one reputable health organisation that is against fluoridation.

1: Dental Fluorosis

There is no argument that having too much fluoride when the teeth are forming will cause dental fluorosis but this isn’t the case for fluoridation. There is little difference in frequency and severity of fluorosis between non-fluoridated and fluoridated areas, something which Barnett-Rose (2014) seems to ignore. The CDC source given was looking at fluorosis as a whole and not at fluoridated vs non-fluoridated, but it states that “community water fluoridation programs were developed to add fluoride to drinking water to reach an optimal level for preventing tooth decay, while limiting the chance of developing dental fluorosis”. If there were any large differences in fluorosis then I would be all for another look into balancing the levels of fluoride in those areas. In fact health authorities in many countries continually monitor research findings for this very reason and that was the reason for the National Research Council (2006) review which did recommend reducing the primary MCL of 4 ppm.

Any increase in fluorosis due to CWF would be in the very mild to mild fluorosis range. The dental fluorosis about which they speak in Warren’s et al. (2009) “Iowa study” is overwhelmingly of the barely detectable nature. The 2009 New Zealand Oral health Survey found very little difference between fluoridated and non-fluoridated areas, in terms of the levels of mild to very mild fluorosis (which has no effect on appearance, form or function of teeth), as shown on the graph below. In fact, Lida & Kumar (2009) have demonstrated mildly fluorosed teeth to be more decay resistant.


The statement that fluorosis is “the first sign of fluoride toxicity” is debatable. What sign of which particular toxicity? Just because there might be other effects which have not yet been shown is not proof that there are other effects. It presumably has been a common feature of teeth through the centuries and is harmless.

The American Dental Association website says:

“Yes, it is safe to use fluoridated water to mix infant formula. If your baby is primarily fed infant formula, using fluoridated water might increase the chance for mild enamel fluorosis, but enamel fluorosis does not affect the health of your child or the health of your child’s teeth”.

The recommendation by health authorities that parents use unfluoridated water to make up formula is a peace-of-mind suggestion, not a firm recommendation. For example the CDC says:

“However, if your child is exclusively consuming infant formula reconstituted with fluoridated water, there may be an increased chance for mild dental fluorosis. To lessen this chance, parents can use low-fluoride bottled water some of the time to mix infant formula”.

For infants and children in their tooth-developing years of 0-8, the upper limit (UL) for fluoride is lower, but only due to a risk of development of mild dental fluorosis. That’s why the UL for daily fluoride jumps to 10mg/day after age 8, once the teeth are formed.

The rest of the “Dental Fluorosis” section in Barnett-Rose (2014) talks about moderate to severe dental fluorosis, which is not caused by community water fluoridation and so is pointless to discuss.

2: Skeletal Fluorosis and Bone Fractures

Again, there is no disagreement that chronic exposure to high levels of fluoride can cause skeletal fluorosis and increase the risk of bone fractures. But you don’t see these problems at levels of 0.7-1.2 ppm in community drinking water. The Institute of Medicine has established that the daily upper limit for fluoride intake from all sources, for adults, before adverse effects will occur, short or long-term, is 10 mg. There is no quality research to show skeletal fluorosis can develop at the levels of 0.7-1.2ppm. Even the source used in Barnett-Rose (2014) says “Crippling skeletal fluorosis may be produced by levels of 10-20 mg/day over 10-20 years”.

National Fluoridation Information Service has released a report this month on fluorosis and concluded:

“There are no known health risks associated with CWF in New Zealand, and no severe dental fluorosis, or skeletal fluorosis, has been found. While fluoride is incorporated into teeth and bones, there is no robust evidence of toxic accumulation of fluoride in other tissues in the body”. It also noted in its conclusion “As with many vitamins and minerals, such as iron, and vitamins A and D, fluoride intakes at high levels can be toxic. However, it is impossible to experience acute fluoride toxicity from drinking water optimally fluoridated at levels between 0.7 mg/L to 1.0 mg/L (MoH, 2009), and there is no evidence of skeletal fluorosis resulting from CWF in New Zealand. It makes sound clinical sense to ingest a substance at a level that achieves maximum benefit with minimal adverse effects (Bowen, 2002)”.

One needs to be careful of cherry picking scientific studies. When you look at all the data you will find bone fracture is not an issue. Vestergaard et al. (2007), in a meta-analysis that used 25 studies, came to the conclusion that “there was no effect on hip or spine fracture risk”. He also noted that “in subgroup analyses a low fluoride dose (< or =20 mg/day of fluoride equivalents) was associated with a significant reduction in fracture risk”. This showed that fluoridation can help bones when at the optimum fluoride levels.

Ingestion of some fluoride is necessary as the bioapatites in our body contain both fluoride and carbonate as normal, natural components. The incorporation of ions like fluoride into bioapatites can change their solubility product by several orders of magnitude according to Driessens (1973). Posner et al. (1963) attribute the improved stability of bone to “the isomorphous substitution of fluoride in the apatite structure”.

3. Pineal Gland and Endocrine Disruption Studies

Fluoride can accumulate in the pineal gland. Calcification of the pineal gland is caused by calcium, phosphate and old age. Because the bioapatites in calcified tissues are actively undergoing mineralisation and remineralisation they easily incorporate fluoride into their structure and this leads to higher concentration of fluoride in calcified tissues than in bones generally. No evidence of harm has been found.

There is no known link to hypothyroidism at the levels we get in water fluoridation. I’m not sure where the evidence for “The fluoride dose capable of reducing thyroid function is low – just 2 to 5 mg per day over several months” from Barnett-Rosie (2014). Her source, the Fluoride Action Network website, points to a study Galletti & Joyet (1958), which says:

“Our aim was to elucidate the inhibitory effect of chronic administration of fluoride upon thyroid function in cases of hyperthyroidism. It was demonstrated that such an action appears only occasionally among persons subjected to massive doses of this substance”.

The study was working with prolonged administration of a daily dose of 2-20 mg (on top of their diet). This was also a very small study of 15 people who suffered from hyperthyroidism. Galletti also noted that

“Despite the relatively large amounts administered (up to 20 mg. of F~ for one injection), neither immediate nor delayed toxic manifestations were observed”.

This demonstrates my point that primary sources should be used, and definitely not activist websites.

The ADA concludes on its fluoridation facts document:

“There is no scientific basis that shows fluoridated water has an adverse effect on the thyroid gland or its function”.

It also states:

“The researchers concluded that prolonged ingestion of fluoride at levels above optimal to prevent dental decay had no effect on thyroid gland size or function. This conclusion was consistent with earlier animal studies”

4. Cancer Studies

Bassin (2006) data presentation did not show how many cases and controls were included in each of the models; and fluoride exposures were estimated rather than measured directly. The authors commented that “Further research is required to confirm or refute this observation”. The NHMRC (2007) observed that:

“Shortcomings in their study mean the results should be interpreted with caution pending publication of the larger study results. Co-investigators of Bassin point out that they have not been able to replicate these findings in the broader Harvard study that included prospective cases from the same 11 hospitals”.

There is no demonstrable link between fluoride and cancer. The American Cancer Society says:

“The general consensus among the reviews done to date is that there is no strong evidence of a link between water fluoridation and cancer”.

The National Cancer Institute says:

“Fluoride in water helps to prevent and can even reverse tooth decay. More than 60 percent of the U.S. population has access to fluoridated water through public water supply systems. Many studies, in both humans and animals, have shown no association between fluoridated water and cancer risk”.

This is backed up by systematic reviews e.g. the York Review (2000) reported “No clear association between water fluoridation and osteosarcoma”. The National Research Council (2006) commented:

“Assessing fluoride as a risk factor for osteosarcoma is complicated by the rarity of the disease and that population is all generally exposed to some level of fluoride”.

SCHER (2010) reported:

“a possible link between fluoride in drinking water and osteosarcoma, but studies are equivocal. No evidence from animal studies to support the link, and thus fluoride cannot be classified as to its carcinogenicity”.

5. Lower IQ’s in Children

It is debatable that Mullenix et al. (1995) interpretation on the study was flawed, it doesn’t matter if it was in a “well-respected peer reviewed journal” or not. Plenty of well-respected journals have released poor papers. One such example was Wakefield’s (1998) claim of a link between vaccines and autism, published in The Lancet.

The study by Mullenix et al. (1995) was refuted by Ross & Daston (1995):

“In summary, much of the ambiguity in the interpretation of these results could have been avoided with information from two concurrent or historical control groups: 1) a group to define the behavioral signature resulting from long term adulteration of the drinking water, and 2) a group to define the behavioral signature of animals with hippocampal damage in this testing system. Such controls are an essential feature of test validation and experimental design. Novel behavioral chemicals of unknown toxicity are dosed, and all possible results interpreted as neurotoxicity. Instead, both positive and negative control materials should be evaluated, and the results linked with well-characterized functional and morphological indices of neurotoxicity.

We appreciate the opportunity to provide our interpretations of this study. We do not believe that the study by Mullenix et al. can be interpreted in any way as indicating the potential for NaF to be a neurotoxicant.”

On top of that, it is also debatable if plasma levels in rodents due to high levels of fluoride are equivalent to those in humans. The National Research Council (2006) discussed the contradictory data used for attempting to show a ratio between humans and rats for blood plasma levels and concluded:

“Dunipace et al. (1995) concluded that rats require about five times greater water concentrations than humans to reach the same plasma concentration. That factor appears uncertain, in part because the ratio can change with age or length of exposure. In addition, this approach compares water concentrations, not dose. Plasma levels can also vary considerably both between people and in the same person over time (Ekstrand 1978)”.

Choi (2012) described 27 studies found majority in obscure Chinese scientific journals. China is not artificially fluoridated and the studies used high levels of naturally occurring fluoride in the well water of various Chinese, Mongolian, and Iranian villages. The concentration of fluoride in these studies was as high as 11.5 ppm. By the admission of the Harvard researchers, these studies had key information missing, used questionable methodologies, and had inadequate controls for confounding factors. These studies were so seriously flawed that the lead researchers, Anna Choi, and Philippe Grandjean, were led to issue a statement in September of 2012. Anna Choi said:

“These results do not allow us to make any judgment regarding possible levels of risk at levels of exposure typical for water fluoridation in the U.S. On the other hand, neither can it be concluded that no risk is present“.

Broadbent et al. (2014) used data from the Dunedin Multidisciplinary Study, which is world-renowned for the quality of its data and rigour of its analysis, and found no significant differences in IQ by fluoride exposure, even before controlling for the other factors that might influence scores. It controlled for childhood factors associated with IQ variation, such as socio-economic status of parents, birth weight and breastfeeding, and secondary and tertiary educational achievement.

6: Benefits from Systemic Fluoride Intake?

For this section I’ll limit the discussion to the benefits of systemic and topical intake of fluoride.

Even if the primary role of fluoride was topical, water fluoridation has a beneficial effect and makes a good delivery system. Consumption of fluoridated food and water enables transfer of fluoride to saliva and biofilms on the teeth. This fluoride, together with calcium and phosphate on the saliva, reduces acid attack on the teeth and so helps prevent tooth decay. Because fluoride concentrations in saliva decrease within an hour or so after brushing, fluoridated water complements use of fluoridated toothpaste. Our teeth are in more regular contact with food and water than they are with toothpaste.

Buzalaf et al. (2011) reports:

“More than 60 years of intensive research attest to the safety and effectiveness of this measure to control caries. In this case, however, it should be emphasized that despite being classified as a ‘systemic’ method of fluoride delivery (as it involves ingestion of fluoride), the mechanism of action of fluoridated water to control caries is mainly through its topical contact with the teeth while in the oral cavity or when redistributed to the oral environment by means of saliva. Since fluoridated water is consumed many times a day, the high frequency of contact of fluoride present in the water with the tooth structure or intraoral fluoride reservoirs helps to explain why water fluoridation is so effective in controlling caries, despite having fluoride concentrations much lower than fluoride toothpastes, for example. This general concept can be applied to all methods of fluoride use traditionally classified as ‘systemic’. In the light of the current knowledge regarding the mechanisms by which fluoride control caries, this system of classification is in fact misleading”.

Featherstone (2000) also demonstrated that:

“The cariostatic effects of fluoride are, in part, related to the sustained presence of low concentrations of ionic fluoride in the oral environment, derived from foods and beverages, drinking water and fluoride-containing dental products such as toothpaste. Prolonged and slightly elevated low concentrations of fluoride in the saliva and plaque fluid decrease the rate of enamel demineralization and enhance the rate of remineralization”.

The main benefit is from topical application but systemic ingestion still plays a role. Buzalaf et al. (2011) also states that:

“Evidence also supports fluoride’s systemic mechanism of caries inhibition in pit and fissure surfaces of permanent first molars when it is incorporated into these teeth pre-eruptively”.

Quality studies continue to show fluoridation to be effective today. Newbrun (1989), Brunelle & Carlos (1990) and Griffin et al. (2007) have proven water fluoridation continues to be effective in reducing dental decay by 20-40%.

National Research Council Report:

I will touch on the National Research Council (2006) report as Rita has asked me to give my assessment and it is used throughout her paper. The 2006 NRC Committee was charged with evaluating the adequacy of the US EPA primary (4 ppm) and secondary (2 ppm) MCLs for fluoride to protect the public against adverse effects, it did not look at the benefits. The EPA’s guidelines are not recommendations about adding fluoride to drinking water to protect the public from dental caries. Guidelines for that purpose (0.7 – 1.2ppm) were established by the U.S. Public Health Service. It reported:

“this report does not evaluate nor make judgments about the benefits, safety, or efficacy of artificial water fluoridation. That practice is reviewed only in terms of being a source of exposure to fluoride”.

After the Committee looked at all relevant fluoride literature, it recommended that the EPA primary MCL for fluoride be lowered from 4.0 ppm. The stated reasons for this recommendation were the risk of severe dental fluorosis and bone fracture with chronic ingestion of water with a fluoride content of 4.0 ppm or greater. No other reasons. Had this Committee had any other concerns with fluoride at this level, it would have stated so and recommended accordingly. Additionally, this Committee made no recommendation to lower the EPA secondary MCL for fluoride, 2.0 ppm which water fluoridation at 0.7ppm is 1/3 of this value.

In March of 2013, Dr. John Doull, the internationally respected toxicologist who chaired the NRC committee, made the following statement:

“I do not believe there is any valid, scientific reason for fearing adverse health conditions from the consumption of water fluoridated at the optimal level.”

Final recommendation of this Committee showed nothing that doubt on the safety of fluoride at the recommended optimal level. It also has no bearing on water fluoridation so using the NRC report to as a reason to stop fluoridation would be misguided.


I have outlined major flaws of the science of this paper, with the major criticism being not using primary sources. There was no assessment of the quality of the evidence. One should start with secondary reviews published in peer-reviewed, high-impact journals, including meta-reviews, review articles, and Cochrane Collaboration reviews; otherwise, high quality clinical trial reports with fairly large number of subjects.

Any further discussions on the ethics or legal matters with fundamental flaws in the science would make any exchange confusing and pointless.

Rita Barnett-Rose’s response to Daniel Ryan’s critique will be posted tomorrow. See Fluoride debate: Response to Daniel Ryan’s critique – Rita Bartlett-Rose

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Fluoride debate: The scientific evidence against fluoridation – Rita F. Barnett

Recently an unpublished paper by Rita F. Barnett, an associated professor of Legal Research and Writing at Chapman University, was heavily promoted by Paul Connett’s Fluoride Action Network and associated social media groups. Although basically a legal paper it did have a comprehensive section on the scientific  aspects of fluoridation.

Rita F. Barnett

She argued that the science indicated that community water fluoridation was neither effective or safe and was criticised for that. One of her critics, Daniel Ryan from the Making Sense of Fluoride group, participated in an exchange with her about the science.

As this has only been available in downloadable pdf format I am posting this exchange over the next few days as part of the ongoing fluoridation debate.

This post today is the section from Rita Barnett’s paper in which she argues that the science does not support community water fluoridation.

Scientific evidence against compulsory water fluoridation

(extract from Compulsory water fluoridation: Justifiable public health benefit or human experimental research without informed consent by Rita F. Barnett.)

Fluoridation proponents have historically characterized those opposing or questioning fluoridation as “irrational, fanatical, unscientific, or fraudulent,” regardless of the legitimate scientific credentials of those opposing fluoridation.64 However, the mounting scientific evidence against fluoridation has begun to persuade an increasing number of scientific researchers and dental and medical professionals, and even some formerly avid fluoride proponents.65

While a comprehensive review of all existing and emerging toxicological, clinical and epidemiological studies weighing against fluoridation or urging further research is beyond the purview of this article, a brief discussion of some current areas of concern follows.

1: Dental Fluorosis

Dental fluorosis occurs when children absorb too much fluoride. This excess fluoride “causes the biochemical signal to go awry, thereby creating gaps in the crystalline enamel structure.”66 When the tooth finally erupts, is it unevenly colored, and may even be pitted and brown.67

Although early fluoride proponents claimed that mild dental fluorosis was the only potential, and relatively rare, negative side effect to systemic fluoride exposure, today about 30-40% of American teenagers show visible signs of dental fluorosis, with the rate as high as 70-80% in some fluoridated areas.68

Exposure to multiple sources of fluoride beyond fluoridated water supplies may partly explain the higher than expected rates of dental fluorosis, the first sign of fluoride toxicity. Indeed, it is nearly impossible today to avoid consuming fluoride even in non-fluoridated areas, since fluoride is now found in fluoridated toothpaste, the pesticide residue on fresh produce, processed food and beverages made with fluoridated water, and many pharmaceuticals.69 Yet, research from the Iowa Fluoride Study, the largest long-running investigation on the effects of fluoride, has indicated that the most important risk factor for dental fluorosis is exposure to fluoridated water.70 Perhaps for this reason, the American Dental Association now recommends that parents use non-fluoridated water for infant baby formula, while the Institute of Medicine recommends that babies only consume a miniscule 10 micrograms of fluoride daily, a near impossible feat when babies are fed infant formula reconstituted with fluoridated water – even where levels are within the “optimal” range of 0.7- 1 ppm.71

Despite the fact that dental fluorosis not only produces unattractive teeth but may also increase the risk of tooth loss, the EPA and other U.S. public health officials downgraded even moderate to severe dental fluorosis from an adverse health effect to a purely cosmetic one.72 This downgrade has been largely perceived as a bow to political pressure rather than a legitimate health risk assessment.73 In any event, “it is widely acknowledged that dental fluorosis is a manifestation of systemic toxicity,” leading to far more serious health risks than unattractive teeth alone.74

2: Skeletal Fluorosis and Bone Fractures

Fluoride, of course, is not equipped with a smart GPS, able to provide benefits to teeth while bypassing bone and other organs of the human body.75 Instead, approximately 93% of ingested fluoride is absorbed into the bloodstream, and while some of it is excreted, roughly 50% is deposited into bone, potentially leading to skeletal fluorosis.76 Skeletal fluorosis is characterized by painful and limited joint movement, spinal deformities, muscle wasting, and calcification of the ligaments.77 Numerous studies have already linked skeletal fluorosis to excess fluoride intake, and although health officials had formerly insisted that skeletal fluorosis would not develop unless a person ingested 20 milligrams of fluoride per day for over 10 years, current research now suggests that doses as low as 6 mg/day can cause early stages of the disease, and that skeletal fluorosis can develop even with fluoride levels as low at 0.7 to 1.5 ppm, the range used in many fluoridation schemes throughout the United States.78 Unfortunately, skeletal fluorosis may go undetected or misdiagnosed because some of the symptoms mimic symptoms of arthritis or other bone diseases, and because many doctors do not know how to diagnose it.79

In addition to skeletal fluorosis, epidemiological studies have now also linked high fluoride exposure to an increase in bone fractures, especially in vulnerable populations such as the elderly and diabetics.80 Related studies have shown that people once given fluoride to “cure” osteoporosis wound up having increased fracture rates.81

3: Pineal Gland and Endocrine Disruption Studies

Researchers have now discovered that an even greater amount of fluoride accumulates in the pineal gland than in teeth and bone.82 The pineal gland is responsible for the synthesis and secretion of the hormone melatonin, which regulates the body’s circadian rhythm cycle and puberty in females, and helps to protect the body from cell damage from free radicals.83 While it is not yet known if fluoride accumulation affects pineal gland function in humans, experiments have already found that fluoride reduced melatonin levels, interfered with sleep-wake cycles, and shortened the time to puberty in animals.84

In addition, studies have now shown that fluoride can contribute to hypothyroidism (an underactive thyroid), which is unsurprising, since fluoride was once used as a prescription drug to reduce thyroid gland function in patients with hyperthyroidism (an overactive thyroid).85 The fluoride dose capable of reducing thyroid function is low – just 2 to 5 mg per day over several months. This is well within the range of what individuals living in fluoridated communities are receiving on a regular basis.86

4: Cancer Studies

Numerous studies have now suggested a link between cancer and fluoride.87 However, perhaps even more disturbing than the evidence supporting the fluoride-cancer link is the evidence suggesting that political and other agendas have played a large part in the outright suppression of this evidence.88

First, in the early 1950’s, Dr. Alfred Taylor, a biochemist at the University of Texas, conducted a series of experiments in which cancer prone mice consuming water treated with sodium fluoride were found to have shorter lifespans than cancer-prone mice drinking non-fluoridated water.89 After discovering that his first round of tests had been contaminated because both groups of mice had eaten food containing fluoride, Dr. Taylor repeated the experiment, and found the same results – a shorter life span for the mice drinking the fluoridated water. However, because these damaging results appeared around the launch time of the early fluoridation schemes, and because public health officials had already come out in staunch support of fluoridation, Dr. Taylor’s work was misrepresented. Specifically, fluoridation proponents falsely claimed that Dr. Taylor had never conducted the second study revealing that the fluoride-cancer link was still present when the necessary controls were put in place.90

Then, in 1990, a study conducted by the U.S. government’s National Toxicology Program (“NTP”) found a positive relation for osteosarcoma (bone cancer) in male rats exposed to different amounts of fluoride in drinking water.91 When NTP downplayed the results in order to avoid a public outcry over compulsory fluoridation, a storm of controversy erupted, with a number of scientists outraged at the failure to report the cancer linked results accurately.92

Finally, in 2006, Elise Bassin and her colleagues at the Harvard School of Dental Medicine published a study in the peer-reviewed journal Cancer Causes and Control, which also showed a link between fluoridation and osteosarcoma in young men.93 Incredibly, Bassin’s own dissertation advisor at Harvard, Chester Douglass, wrote a commentary in the same journal warning readers to be “especially cautious” about Bassin’s results. This lead to yet another controversy, with Bassin’s defenders calling for an ethical investigation of Douglass, since, as it turned out, Douglass had some conflicts of interest and was the editor in chief of a newsletter for dentists funded by Colgate. 94

5: Lower IQ’s in Children

Researchers have also begun to focus on the damaging effects fluorides appear to have on the human brain. In the 1990’s, researcher Phyllis Mullenix studied the brain and behavioral effects of sodium fluoride on rats.95 Her study revealed that pre-natal exposure to fluoride correlated with life-long hyperactivity in young rats, while post-natal exposures often had the opposite, “couch potato” effect.96 Although Mullenix’s research was published in a well-respected peer reviewed journal, the fluoride proponents attacked her methodology and declared her results flawed.97 Since then, however, forty-six other studies have emerged showing a connection between excess exposure to fluoride and lowered IQ’s in children, with 39 of the 46 finding that elevated fluoride exposure is associated with decreased IQ, and 29 of the 31 animal studies showing that fluoride exposure impairs the learning and/or memory capacity of animals.98

In 2012, after conducting a meta-analysis of 27 of the fluoride-human IQ studies, conducted mostly in China, a team of scientists from Harvard’s School of Public Health and China’s Medical University in Shenyang concluded that the studies suggested an average IQ decrease of about seven points in children exposed to raised fluoride concentrations.99 In 2014, one of the chief authors of the initial 2012 meta-analysis, Harvard professor Philippe Grandjean, concluded in a follow-up article that “our very great concern is that children worldwide are being exposed to unrecognized toxic chemicals that are silently eroding intelligence,” and that fluoride’s effect on the young brain should now be a “high research priority.”100 Notably, a majority of the 27 studies analyzed were of water fluoride levels of less than 4 mg/L, which falls under the allowable concentrations of fluoride under current EPA regulations.101

6: Benefits from Systemic Fluoride Intake?

With so many current studies linking fluoride to serious health risks beyond dental fluorosis, the question remains whether fluoride’s public health benefits outweigh any and all of these risks. The Centers for Disease Control has deemed water fluoridation one of the “top ten health achievements of the 20th Century.”102 Proponents therefore insist that even if there are a number of recognized risks of fluoridation, there has been enough evidence to show that these risks are remote and are far outweighed by the benefits.103 Yet much of the available scientific data today suggests that any benefit from fluoride in terms of preventing tooth decay has been from topical application, rather than systemic ingestion.104 Moreover, even the benefits of topical fluoride treatments have been recently questioned, since most dental caries today are in the “pits and fissures” of the molars rather than on the flat surface of teeth, and various studies have now indicated that fluoride has no impact on the pits and fissures.105

Research conducted over the last twenty years has also shown that the estimated reduction in tooth decay due to compulsory water fluoridation has been grossly exaggerated. While at one time proponents boasted a 50-65% reduction in tooth decay, a great deal of current evidence suggests the real percentage is significantly lower, with some studies showing no measurable reduction at all. 106 Confounding claims of benefit even further, numerous studies have shown a substantially similar decline in the dental caries rate in countries that do not fluoridate, and in areas within the United States that remain unfluoridated.107

Nor have the asserted economic benefits of compulsory water fluoridation come to fruition. In fact, a number of economic evaluation studies have indicated that the costs of dental care may actually be higher in fluoridated communities than in non-fluoridated communities.108

Unfortunately, rather than considering the new data objectively, public health officials and dental lobbies spearheading fluoridation schemes often ignore, reject, or suppress the evidence that does not toe the pro-fluoride party line.109 Nevertheless, as evidence against fluoridation continues to 20 Compulsory Water Fluoridation [23 Sept 14 accumulate in a variety of health risk areas, two conclusions seem readily apparent. First, there remain significant unanswered questions about the risks and benefits of systemic fluoride, and further research before imposing or continuing fluoridation schemes seems not only scientifically prudent, but ethically necessary. Second, it is no longer acceptable for public health officials to simply dismiss the accruing negative data and to continue to insist that the levels of fluoride children and adults are receiving on a daily basis are without any serious health consequences. Fortunately, tentative moves by the EPA and other federal agencies suggest that at least some public health authorities are inching towards similar conclusions.


64 See e.g. Hileman, supra note 18, at 4. See also Graham, supra note 17, at 195 (noting a pro-fluoridation report characterizing fluoride opponents as follows: “The opposition stems from several sources, chiefly food faddists, cultists, chiropractors, misguided and misinformed persons who are ignorant of the scientific facts on the ingestion of water fluorides, and, strange as it may seem, even among a few uniformed physicians and dentists.”). See also Leila Barraza, Daniel G. Orenstein, Doug Campos- Outcalt, Denialism and Its Adverse Effect on Public Health, 53 JURIMETRICS J. 307, 307 (calling those who oppose fluoridation “denialists” who “misuse science to advocate positions that contradict the overwhelming weight of existing evidence”).

65 See e.g., John Colquhoun, Why I Changed My Mind About Water Fluoridation, 41 PERSPECTIVES IN BIOLOGY AND MEDICINE 1 (1997); Dr. Hardy Limeback, Why I Am Now Officially Opposed to Adding Fluoride to Drinking Water, FLUORIDE ACTION NETWORK (April 2000), http://fluoridealert.org/articles/limeback/; J. William Hirzy, Dr. William Hirzy, Former Head of EPA’s Headquarters Union Recommends Portland Flush Fluoridation Proposal (March 2013), FLUORIDE ACTION NETWORK, http://fluoridealert.org/content/hirzy_portland/.

66 Fagin, supra note 26, at 78.

67 Fagin, supra note 26, at 78; Hileman, supra note 18, at 9.

68 See Beltran-Aguilar, et. al., Prevalence and Severity of Dental Fluorosis in the United States, 1999-2004, NCHS DATA BRIEF NO. 53 (2010), http://www.cdc.gov/nchs/data/databriefs/db53.pdf. See also Czajka, supra note 13, at 125.

69 Beltran-Aguilar, supra note 68; Peckham, supra note 13, at 165.

70 Fagin, supra note 26, at 79 (children exposed to fluoridated water were 50% more likely to have dental fluorosis than children living in non-fluoridated areas).

71 Peckham, supra note 13, at 165-66.

2 See Hileman, supra note 18 at 10.

73 Id.

74 Peckham, supra note 13, at 166.

75 Limeback, supra note 65 (“it is illogical to assume that tooth enamel is the only tissue affected by low daily doses of fluoride ingestion.”); Colquhoun, supra note 65 (“Common sense should tell us that if a poison circulating in a child’s body can damage the tooth-forming cells, then other harm also is likely.”).

76 Czajka, supra note 13 at 125.

77 Null, supra note 17, at 74.

78 Czajka, supra note 13, at 125.

79 Null, supra note 17, at 74; Hileman, supra note 18, at 13.

80 Fagin, supra note 26, at 79.

81 See Null, supra note 17, at 74-75.

82 Jennifer Luke, Fluoride Deposition in the Aged Human Pineal Gland, 35 CARIES RESEARCH 125-128 (2001). See also Czajka, supra note 13, at 126.

83 Fluoride Action Network, Pineal Gland, FLUORIDEALERT.ORG, http://fluoridealert.org/issues/health/pineal-gland/ (last visited June 25, 2014) (discussing/listing pineal gland studies).

84 Id.

85Fluoride Action Network, Thyroid, FLUORIDEALERT.ORG, http://fluoridealert.org/issues/health/thyroid/ (last visited June 25, 2014) (discussing/listing numerous thyroid studies).

86 Null, supra note 17, at 71. See also Fluoride Action Network, Endocrine, FLUORIDEALERT.ORG, http://fluoridealert.org/issues/health/endocrine/(last visited June 25, 2014) (discussing/listing numerous endocrine system studies).

87 Fluoride Action Network, Cancer, FLUORIDEALERT.ORG, http://fluoridealert.org/issues/health/cancer/ (last visited June 25, 2014) (discussing/listing numerous cancer studies).

88 See e.g., Null, supra note 17, at 77; Graham, supra note 17, at 229-240.

89 Null, supra note 17, at 77.

90 Id.

91 NTP Toxicology and Carcinogenesis Studies of Sodium Fluoride in F344/N Rats and B6C3F1 Mice (Drinking Water Studies), 393 NATL. TOXICOL. PROGRAM TECH REP SERV. 1-448 (1990).

92 Null, supra note 17, at 78-79.

93 E. B. Bassin et. al., Age Specific Fluoride Exposure in Drinking Water and Osteosarcoma, 17 CANCER CAUSES & CONTROL 421-28 (2006) (finding an association between fluoride exposure in drinking water during childhood and the incidence of osteosarcoma among males but not consistently among females). See also S Kharb et. al., Fluoride Levels and Osteosarcoma, 1 SOUTH ASIAN J. CANCER 76-77 (2012) (finding positive correlation between fluoride and osteosarcoma).

94 Fagin, supra note 26, at 80. 95 Phyllis J. Mullenix, Neurotoxicity of Sodium Fluoride in Rats, 17 NEUROTOXICOLOGY AND TERATOLOGY 169-177 (1995).

96Fagin, supra note 26, at 80. See also Null, supra note 17, at 74 (describing an ad campaign promoting a fluoridated spring water “for kids who can’t sit still.”).

97 Fagin, supra note 26, at 80.

98 Fluoride Action Network, Brain, FLUORIDEALERT.ORG, http://fluoridealert.org/issues/health/brain/ (last visited June 25, 2014) (discussing/listing numerous brain studies).

99 See Anna L. Choi et. al, Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis, 120 ENVIRON. HEALTH PERSPECT. 1362-1368 (2012).

100 Philippe Grandjean & Philip Landrigan, Neurobehavioural Effects of Developmental Toxicity, 13 THE LANCET NEUROLOGY, 330-338 (2014) (“untested chemicals should not be presumed to be safe to brain development, and chemicals in existing use and all new chemicals must therefore be tested for developmental neurotoxicity.”). See also Diana Rocha-Amador, Decreased Intelligence in Children and Exposure to Fluoride and Arsenic in Drinking Water, Cad. Saude Publica, Rio de Janeiro, 23 Sup. S579-587 (2007).

101 See discussion infra Sec. III.

102 CDC FLUORIDATION, supra note 18.

103 Hileman, supra note 18, at 2.

104 See Czajka, supra note 13, at 127.

105 See e.g., Letter from Dr. Paul Connett to Scientific Committee on Health and Environmental Risks, the European Committee, at #7 (March 30, 2009), available at http://www.fluoridealert.org/wp-content/uploads/scher.march_.2009.pdf (“Since 1950, it has been found that fluorides do little to prevent pit and fissure tooth decay…This is significant because pit and fissure tooth decay represents up to 85% of the tooth decay experienced by children today.”).

106 Hileman, supra note 18, at 5.

107 Hileman, supra note 18, at 6-7. See also Michael Connett, Tooth Decay Trends in Fluoridated vs. Unfluoridated Countries (March 2012), FLUORIDEALERT.ORG, http://fluoridealert.org/studies/caries01/ (noting that decay rates in non-fluoridated countries have declined at the same rate as those in fluoridated countries).

108 Hileman, supra note 18, at 7. 109 See e.g., Voices of Opposition Have Been Suppressed Since Early Days of  Fluoridation, CHEMICAL & ENGINEERING NEWS (August 1, 1988), available at

Daniel Ryan’s first response to Rita’s unpublished paper will be posted tomorrow – see Fluoride debate: A response to Rita Barnett-Rose – Daniel Ryan

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Download The Fluoride Debate


I have put together the posts from the exchange between Paul Connett and me in the form of a single document. This will be more convenient for anyone who wishes to browse the articles. Hunt down details or refer to material off-line. Click in the image or this link to download a pdf of The Fluoride debate document.

For those who have not followed this exchange here is a bit of history and explanation from the document.

This is a collection of articles written by Paul Connett and Ken Perrott in their exchange of opinions on the fluoridation of drinking water and related issues. While loosely titled The Fluoride Debate this was in no way meant to be a debate in the gladiatorial sense. It was not about “winners” and “losers.” Our intention was to discuss the science in a format encouraging good faith discussion and intelligent participation from commenters.

I leave it to readers to decide how successful, or otherwise, we have been in this.

Introducing the authors

The authors in this “debate’ have similar academic and professional backgrounds. Both have PhDs in chemistry, worked as research chemists and are now retired. Neither of us have done original research on fluoridation specifically, although both have become involved in the public discussion of it since there retirements.

Paul Connett is an executive director of the Fluoride Action Network and campaigns throughout the world against fluoridation. He is, together with James Beck & H. Spedding Micklem, author of the book “The Case Against Fluoride.” Paul has made several speaking tours in New Zealand as part of his campaign and will have another tour in February, 2014.

Ken Perrott is a retired research chemist. These days he writes a blog, Open Parachute, which deals issues related to science, human rights, philosophy and religion. Many of his articles have argued against pseudoscience and the misrepresentation of science. He has written a number of articles on scientific issues related to fluoridation.

Format of debate

The exchange occurred as posts on the blog Open Parachute. Paul originally proposed it as 5 pairs of articles with Paul starting and raising specific arguments against fluoridation followed by my reponse.– Paul Connett’s specific argument first with my response second. I thought this would be a convenient size for a series of blog articles.

Paul’s first article went live on October 30, 2013. Without the discipline of an external moderator the series ended up a longer than originally planned – we ended up with 8 pairs of articles, with my final closing article posted on January 23, 2014.

Responding to requests from commenters about my own personal, rather than scientific, motivations I also posted an extra article Why I support fluoridation on November 11. Inevitably its content was also debated.

Editing of articles

The articles here are basically the same as originally posted in the debate. I have corrected some typos and added reference lists to my own articles recognising that the hot links provided in a blog article may not be suitable for all readers of this document. I have avoided editing or altering Paul’s articles except for a few minor issues like adjusting image size.

Comment discussions

Many others, representing both sides of the “debate,” participated in this exchange through the comments section of each article. Some commenters were very well informed, often with professional experience related to fluoridation. There were almost 2000 comments in total with many of them containing useful information and citations. Unfortunately it is not feasible to include the comment discussion here but I urge interested readers to browse through them on-line.

Links to debate

You can easily find original blog articles, together with comments, at the link Fluoride Debate.

Advice to readers

Such lengthy articles, and so many of them, might be intimidating to some readers. My advice is to browse, read the articles that interest you or cover issues of interest. I imagine only the most dedicated reader would start at the beginning and read to the end.

Any reader wishing to make contact with me can do so via my About me blog page.

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Fluoride debate: Final article – Ken Perrott

This is the last, final, article in the Fluoride debate. There will be nothing more. It is  Ken Perrott’s response to Paul Connett’s last article Fluoride debate: Paul Connett’s Closing statement.

For Paul Connett’s original article see – Fluoride debate Part 1: Connett.

“Skeptical scrutiny is the means, in both science and religion, by which deep thoughts can be winnowed from deep nonsense.”― Carl Sagan

Paul has used his right of reply and it really is time to close off this exchange.

I am not going to sieve through Paul’s long article and comment point by point – we are well past this. Instead I will discuss a basic issue central to the exchange (Paul’s reference to “weight of evidence analysis”) and show with several examples how superficial, and unscientific, Paul’s understanding of the approach is.

“Weight of evidence” – different things to different people

Weight of evidence can mean anything from a vague metaphorical description to a methodological approach or a theoretical/conceptual framework. Paul doesn’t clarify any further, but when he talks about balancing one set of studies or papers against another I find his concept very mechanical. It reminds me of the way the Hamilton City Council treated the submissions to last year’s hearings on the fluoridation issue (see my article When politicians and bureaucrats decide the science). Council staff reported:

“Of the 1,557 submissions received 1,385 (89%) seek Council to stop the practise of adding fluoride to the Hamilton water supply. 170 (10.9%) seek Council to continue the practise of adding fluoride and 2 (0.1%) submitters did not indicate a stance.”

Council, and Council staff, were impressed by these numbers – after all, place the submission printouts on a kitchen scales and of course the anti-brigade wins! Silly, I know, but this was one of the arguments staff supplied to council for ignoring the result of the referendum (where almost 70% supported fluoridation), at their November 2013 meeting. This extract from the draft resolution submitted by staff:

“All evidence has been considered carefully by Council and, while finely balanced, Council preference is to continue not to fluoridate the city water supply because: . . .

vi. Not fluoridating the city water supply reflects the majority of views expressed through the Council tribunal process.”

The silliness of such an approach is obvious when one starts to consider the quality and not the quantity of submissions. Here are a few examples from those opposing fluoridation:

Submission No 58:

I do not believe there is enough evidence to support the mass medication of our water supply’s for the good of all people. It is our right to choose to medicate ourselves with fluoride not the government right to force this medication I believe the fluoride in our water is toxic and needs to be stopped.

Submission 60:

Water Fluoridation is medication ‐ even if the pro fluoridationist say it is not. Council does not have the right to medicate the water. Please STOP!

Submission No 61:

From what I have come to understand, Fluoride is a toxin that has been and will continue contribute to chronic long term health illnesses. Fluoride a toxic substance we don’t want in our water supply for our younger generation to be exposed to.
Regards Connie

Submission No 65:

I do not want N0 KEMICALS into my drinking water.Thank you very much,Dorel”

Submission No 975:

“There is no acceptable reasoning to mass dose the whole population. There is a significant amount of information describing the side effects of Fluridation of the water supply. If people want extra Fluoride then they can take tables. 90% + of the fluoride added to the town supply ends up in the environment. There are more than 100 pesticides manufactured from Fluoride.”

Submission No 237:

I love New Zealand, it’s such a beautiful country. Fluoride is not necessary in the water supply. Please let people make their own choice about whether or not they want to ingest fluoride. It should not be forced upon anyone by adding it to the water supply. This is just plain and simply wrong!”

The local anti-fluoride activist organisation, the Fluoride Action MNetwork of NZ (FANNZ), promoted such meaningless submissions by proving a template form for their supporters. They were going for quantity and not quality – they are political activists, not scientists.

This shows why I reject the mechanical “weight of evidence” approach Paul often seems to be advocating. He certainly fights hard to avoid consideration of the quality of evidence he uses.

I can only agree with a “weight of evidence” approach if it is qualitative, not simply and mechanically quantitative. In fact, I would avoid the term and instead say our approach should be a balanced one, looking (as far as practicable) at all the evidence and considering it critically and intelligently.

Hence the quote from Carl Sagan at the head of this article.

I don’t think Paul does this. I show this in my comments and responses below.

From logical possibility to conspiracy

Paul’s book, The Case Against Fluoride, provides clear examples of a formula he uses to cast doubt on existing science, build up a library of claimed negative effects of fluoride in the human body and to suggest the scientific community conspires to suppress research findings and prevent important research from going ahead. It’s the sort of stuff ideologically driven opponents of fluoridation lap up enthusiastically. These tactics are not new – we have seen it all before with the creationists and the climate change deniers.

This formula has 3 steps:

1: Advance a claim with no real evidence. This can be done in several ways.

A): Establish a logical possibility. Paul uses a lot of “possibles,” “mays,” etc., in his book. No research evidence at all is required for this – just speculation and suggestion. For example:

“. . . if fluoridation were to increase the rates of hip fracture in the elderly, it would be serious and certainly grounds in itself to eliminate water fluoridation.” (p174).

“. .  a possible mechanism exists whereby fluoride could bring about an excessive production of TSH from the pituitary. This may help explain why . . .” (p163).

“These speculations need to be investigated.”     “Although more difficult to prove, it is reasonable to assume that many of the effects seen in vitro can occur in the whole body.” (p125)

“The bone is the principal site for fluoride accumulation within the body, and the rate of accumulation is increased during periods of rapid bone development as occurs in growth spurts during childhood. Thus, the cells in the bone are exposed to some of the highest fluoride concentrations in the body.” (p182)

This last speculation is fallacious as fluoride exists as a structural component of the solid bioapatites in the bone – not in solution – so the term “concentration” is misleading.

B): Use poor research evidence. He often uses the old trick of implying a cause from a correlation, or using research papers who have relied on this fallacy.

The graph below illustrates the fallacy. Most of us find the suggestion eating organic food is the cause of autism silly and we are not at all convinced – despite the excellent correlation. Maybe there are a few people who are so hostile to organic food that they take this suggestion seriously – we can see how their bias might lead them to claim this as evidence and even promote their story with such figures.

But replace the organic food sales with a vaccination statistic – we have a demographic who serious believe vaccinations are harmful and would easily lap up such a fallacious figure. (We are getting a bit close to the bone here – Paul’s Fluoride Action Network (FAN) is organisationally aligned with anti-vaccination (National Vaccine Information Center), anti-GM (Institute for Responsible Technology), and similar outfits through the Health Liberty Coalition.)

Now do the same with a fluoridation statistic and we are getting into very familiar territory. Think Declan Waugh and his graphs showing correlations between fluoridation and practically every illness known to humanity. In fact, Declan Waugh is doing this for autism on his Facebook page. Here is his graph.

Another approach is to just rely on poor quality research – selected to fit his desired conclusions. Consider Paul’s obsession with poor quality Chinese research papers showing a negative correlation of IQ and fluoride concentration in drinking water. These studies have problems with IQ measurement and confounding factors. How can one seriously claim causation when the studies don’t consider, for example, detailed analysis of education and family social conditions. Or other more important contaminants in the environment,

Paul sort of admits speculation or reliance on poor quality research but quickly leaves his admission behind in his eagerness to claim harmful effects:

“there are about twenty studies (albeit with questioned methodologies in some cases) suggesting potential damage to the brains of young children” (p156).”

“Although the validity of the scoring methods used for fractures is acknowledged by the authors to be questionable, this is a potentially important finding,” (p170)”

“At present there is no direct and unassailable proof that fluoridation per se harms anyone’s thyroid. This may be due to the paucity of studies conducted;” (p164)

“We emphasize that proof that fluoride acts on the thyroid in these ways in vivo is still lacking. Further research is needed, but, meanwhile, the mechanisms are plausible and based on existing science.” (p163).

“Although there is no direct evidence that fluoride can inactivate deiodinases, it is well known as an inhibitor of many enzymes, and the hormonal derangements reported in fluoride-exposed people have been interpreted in terms of effects on deiodinases.” (p162)

Paul builds his arguments on very flimsy foundations. He often admits as much but attempts to confound his readers with a fair bit of hand waving and Gish galloping.

2: Collect together any sources which can be interpreted to support the speculation. This may often need a bit of dredging – obscure journals or newsletters, comments recorded at meetings, foreign language sources, etc. Here a naive mechanical “weight of evidence” approach is useful as a pile of Byelorussian, Chinese, Indian, etc. papers from obscure or poor quality sources, often newsletters or reported statements and not scientific papers, weigh a hell of a lot more than one or two papers from reputable journals, by reputable research teams, who report contrary findings.

And of course the well-known problem of lack of reporting negative effects weighs in at zero.

Paul is very proud of the 80 pages of citations in his book. But many of them are repeated several time, are from sources not normally considered for scientific citation, or from sources difficult to track down. Very many of the citations are to his own activist FAN web site. A particularly disturbing aspect of the last sources (often used when referring to translation of foreign language material) is that very often the links lead nowhere. They have either been lost during web site reorganisation or may never have even existed. Who is to know?

3: Use the lack of reputable sources for his claims as evidence of a conspiracy. Paul can “double dip” with the “missing” research and publications from credible reasearch teams and journals. He records paucity of evidence from credible sources to support his own claims relying on poor quality sources, then implies the lack of material indicates at least an unwillingness to research problems or at worst a conspiracy not to do the research and/or hide the results. Of course such descriptors of unwillingness or conspiracy can also be turned on researchers or publications with contrary evidence. He can discount them by suggesting links with industry or personal bias – hence introducing a sort of negative quality to good research while refusing to allow judgement on the quality of the bad research.

For example:

“Most of the concerns about the immune system are largely speculative; once again the scarcity of literature on this reflects a lack of interest by governments that promote fluoridation. The same can be said about reproductive effects; despite an extensive literature indicating that, at high levels of exposure, effects of fluoride on the reproductive system have been observed in a wide range of animals and reptiles, very few human studies on the subject have been published or even undertaken.” (p197)

“The failure to explore the plausible connection between fluoridation and arthritis in any fluoridating country is difficult to understand. It is particularly surprising since the causes of most forms of arthritis (e.g., osteoarthritis) are unknown but are usually associated with the aging process. For those living in fluoridated communities the aging process will coincide with lifelong accumulation of fluoride in their bones and joints.” p170/171)

“We do not claim that these IQ studies add up to conclusive evidence that water fluoridation impairs cognitive development. . . . . it is wise to sit up and pay attention. The health authorities and governments of fluoridating countries show little sign of doing that.” (p156)

“A small minority of people, perhaps 1 percent, appear to be acutely sensitive to exposure to fluoride at the concentrations present in fluoridated water. The wide range of signs and symptoms resemble those seen in poisoning with larger amounts of fluoride. These findings date from the 1950s. However, far from leading to more extensive studies, they were ridiculed when introduced and have since been largely ignored.” (p136)

Fluoridation and IQ

Paul’s mechanical and selective understanding of “weight of evidence” sticks out like a sore thumb when he claims fluoride influences development of the child’s brain. Even though he notes the mainly Chinese studies he relies on had “questioned methodologies in some cases” (p156 of his book) this is perhaps his most favourite claim for rejecting fluoridation. In his last article he even spent some time developing a margin of error from the studies – rather previous, I think, as he had not established that the data he used was reliable or indicated causation

The European Scientific Committee on Health and Environmental Risks (2010) took a more intelligent and critical approach to the Chinese studies. This from their document Critical review of any new evidence on the hazard profile, health effects, and human exposure to fluoride and the fluoridating agents of drinking water:

“A series of studies on developmental effects of fluoride were carried out mostly in China. They consistently show an inverse relationship between fluoride concentration in drinking water and IQ in children. Most papers compared mean IQs of schoolchildren from communities exposed to different levels of fluoride, either from drinking water or from coal burning used as a domestic fuel. All these papers are of a rather simplistic methodological design, with no – or at best little – control for confounders, e.g., iodine or lead intake, nutritional status, housing condition, parent’s education level or income.”

This document concluded:

“Available human studies do not allow concluding firmly that fluoride intake hampers children’s neurodevelopment. A systematic evaluation of the human studies does not suggest a potential thyroid effect at realistic exposures to fluoride. The absence of thyroid effects in rodents after long-term fluoride administration and the much higher sensitivity of rodents to changes in thyroid related endocrinology as compared with humans do not support a role for fluoride induced thyroid perturbations in humans. Limited animal data cannot support the link between fluoride exposure and neurotoxicity,
noted in the epidemiological studies, at relevant non-toxic doses. SCHER agrees that there is not enough evidence to conclude that fluoride in drinking water may impair IQ.”

The NZ National Fluoridation Information Service (2013) also critically reviewed literature on this issue (see NFIS Advisory A review of recent literature on potential effects of CWF programmes on neurological development and IQ attainment).They concluded:

“The available evidence raises the possibility that high levels of fluoride in drinking water may have subtle effects on children’s IQ. However all of these studies have limitations in design and analysis, a clear dose-response relationship between DWFCs and assessed IQ are often not evident. The study authors are frequently very cautious in their comments, and several noted that any indicated negative effect applied only to high DWFCs. An hypothesis of fluoride neurotoxicity would also be supported by some experimental animal studies, however the great majority of these have only considered high fluoride intakes.

However collectively the data described are not robust enough to draw a firm conclusion that high fluoride levels in drinking water supplies contribute to retarded development of children’s brains. Also there is no clear evidence to suggest an adverse effect on IQ at lower fluoride intakes such as that likely to occur in New Zealand, where fluoridated water supplies contain fluoride in the 0.7 to 1.0 mg/L range.

Thus the balance of current scientific evidence does not suggest any risk for the development of full IQ potential for New Zealand Children from current community water fluoridation initiatives, where maximum DWFCs are 1 mg/L.”

Paul will respond that the studies were good enough to warrant further investigation but then he alleges that western researchers are either willfully ignoring these studies or even conspiring to suppress them and refuse to investigate further.

He never considers that, perhaps, the lack of better quality studies really is evidence of lack of effect – given the reluctance to publish studies with nil results.

Think about it, if there really was this effect from salt, milk or water fluoridation wouldn’t we be aware of it by now? After all, many countries do collect the sort of data about their populations, especially children, which would show any effect.

Maybe publication of the Choi et al (2012) meta-review will encourage more specialists to extract this data in their own countries and publish analyses. I personally know of one such study in New Zealand which shows no IQ effect of fluoridation. This study is of higher quality than the ones Paul relies on because  the data was sufficiently extensive to allow consideration of confounding effects (eg. breastfeeding, education, income level, etc.). A paper has recently been submitted for publication so unfortunately I cannot offer a citation until it is “in press.”


Again, the importance Paul gives to a single study on fluoride and osteosarcoma illustrates his mechanical and selective approach to “weight of evidence.” He has not bothered including either the study by Comber et al (2011) of this issue in Ireland or the study by Levy & Leclerc (2012) for the US. Possibly because both of these concluded that water fluoridation has no influence on osteosarcoma incidence rates.

The NZ National Fluoridation Information Service (2013) briefly considered this literature and cancer incidence rates for New Zealand (see Community Water Fluoridation and Osteosarcoma – Evidence from Cancer Registries). Their conclusion:

“The analysis confirms that osteosarcoma is extremely rare in New Zealand with only 127 new cases registered during this period averaging 14.1 per year. The peak age is 10 to 19 years for both sexes. These rates indicate that there is no difference in the rates of osteosarcoma cases between areas with CWF and areas without CWF for both sexes, findings which are consistent with the two international studies.”

But, I guess, not consistent with the one study Paul relies on! A study Paul described as “unrefuted.”  See what confirmation bias does to “weight of evidence?” Although his “unrefuted” strangely conflicts with his qualification about this research in his book:

“The evidence that fluoride causes osteosarcoma is not clear-cut. The studies of the relationships in both animals and humans are mixed.” (p 181)

Update: Here’s another paper published this moth which I guess Paul will studiously avoid. Blakey et al (2014). Is fluoride a risk factor for bone cancer? Small area analysis of osteosarcoma and Ewing sarcoma diagnosed among 0-49-year-olds in Great Britain, 1980-2005.

Breast feeding and the naturalistic fallacy

I understand Paul’s points about dose and dosage – they are not difficult concepts. Obviously they are important when we consider ingestion of fluoride and other environmental elements by infants. My reading indicates that those involved in health advice and regulation do consider dosage when discussing fluoride. I am at a loss to know why Paul thinks this issue is being avoided.

Paul keeps returning to the low level of fluoride in breast milk so I can’t help think he is still trapped by the naturalistic fallacy. He even links this to IQ claiming “whether by accident or by evolutionary “design” mother’s milk is protective against lowered IQ.”

Paul may make some mileage out of the naturalistic fallacy if he stays with fluoride, but bring in the other trace elements which present problems because of deficient levels in human breast milk and the fallacy has far less credibility.

A brief scan of the literature shows breast fed children are prone to some microelement deficiencies. For example, Kodama (2004) and Domellöf, et al (2004) report deficient levels of zinc, selenium and iron in breast milk. Supplementation of breast-fed infants with micronutrients, including fluoride, is sometimes recommended.

Hastings project

Paul’s treatment of this issue shows how simple his concept of “weight of evidence” is. He relies only on one-sided discussions by Colquhoun (1987), Colquhoun & Mann (1986), and Colquhoun & Wilson (1999). He seems not to have done anything to check the original papers from the project and relies on a single out-of-context letter from a bureaucrat which he interprets  to his own satisfaction.

  1. Paul adamantly and publicly declares the Hastings fluoridation project a “fraud.” That is an extremely serious charge in the scientific community – scientific   fraud is one of the worst accusations possible and usually leads to loss of career. It is unprofessional to make such a charge without being prepared to pursue it legally. I question the ethics of such an attack on people who are no longer here to speak in their own defense.
  2. Paul says:
    “What convinces me the final report was a fraud was the authors did not mention the change in diagnosis when claiming the drop in tooth decay was due to fluoridation.”
    Yet he does not reference the “final report” or show any indication he has checked this charge rather than take it on trust from his anti-fluoridation sources.
  3. He claimed in his second to last article that the decision to drop Napier as a control city was made for “bogus reasons” – yet gave absolutely no evidence to support such a serious claim. He now wants to  avoid that responsibility by saying the issue (his claim) is a “red herring.” Sorry Paul, one should not avoid responsibilities – if you wish to make a serious allegation be prepared to back it up or withdraw and apologise –  not run away from it.

I know from experience the complexity of long term trials involving many people doing different jobs. It is easy to take a bureaucratic letter out of context, oversimply or misinterpret problems of personal approaches to methodology and ignore the fact that managers of such trials inevitably face difficulties from factors outside their control. As for reporting findings, the data amassed and details of methodology and their changes can be mind-boggling for an outsider who attempts an understanding.

I will not pretend to have got my head around that project but here are a few observations:

  1. The findings from the trial were presented as scientific papers in the New Zealand Dental Journal (Ludwig and Ludwig, et al. 1958, 1959, 1962, 1963, 1965, 1971). The issues with Napier, originally proposed as a control, are discussed by Ludwig et al (1960), Ludwig & Healy (1962) and Healy et al (1962). Paul does not seem to have consulted any of these papers yet he considers his “weight of evidence” enough to make serious charges of “bogus” and “fraud!”
    The authors did not trumpet their study “showed that fluoridation was a great success” – scientists are usually more circumspect. In this case conclusions were more along the lines “The results obtained in Hastings during a period of  75-78 month’s fluoridation are very similar to results obtained overseas after a comparable period of fluoridation.” (Ludwig 1962).
  2. The important data was reported in papers from 1958 – 1971. These are very brief but all include the statement that further information on methodology, data and statistical analysis is available to interested people. The details Paul’s seems to want may be in that unpublished “further information.”
  3. Colquhoun & Mann (1986) and Colquhoun & Wilson (1987) both quote from unpublished reports and communications where discussion of diagnostics and methodological changes occurred. Colquhoun and Mann even report that researchers believed evidence from the Napier data indicates these changes did not have an overriding effect. Even a simple glance at the published data shows that the decline in tooth decay was not restricted to the early period where diagnostic and methodological changes would have been expected to exert any effect. Compare the plots below.


Hastings data shows similar improvement in oral health even if project had started in 1957. Plots are for different ages.

I think Paul is irresponsible to make such damning charges of “fraud” without considering all the material. He actually has no evidence at all the project was a “fraud” or that the reasons for dropping Napier as a control were “bogus.” His behaviour is unprofessional.

The problems with longitudinal studies

There are inevitable problems with longitudinal trials of the sort which the Hastings Project eventually became. They are influenced by undetected confounding factors and hence can be difficult to interpret. This may not have been sufficiently recognised at the time and that may have coloured interpretation of the results.

But let’s not forget that much of the harsh criticism of fluoridation made by Colquhoun (1997) and Diesendorf (1986) rely on their own biased interpretation of such longitudinal trails. And today’s anti-fluoridation propagandists make the same mistake even though we now know better. Paul himself used the WHO data showing improvement in oral health in many countries in his first few articles to argue that fluoridation had no effect. He did not consider the multifactorial causes of that improvement or mention that where measurements made in single countries (like Ireland) clear differences between fluoridated and unfluoridated areas were seen.

Should we now accuse Paul of “fraud” because he made no mention of the full Irish data in his claim that the WHO data showed fluoridation ineffective?

Paul continually avoids systemic role of fluoride

He does this by stressing the surface mechanism initiating caries is “topical” and not “surface” and works hard to imply “topical application” methods are required. He has conceded to including the word “predominantly” when referring to the surface mechanism but seems not to understand the meaning of the word.

My dictionary definition for “predominant” is “Most common or conspicuous; main or prevalent.” The word does not mean “only” as Paul seems to assume.

Neither is tooth decay simply about the initiation of caries. It also involves the strength and hardness of the teeth where systemic fluoride plays a beneficial role – especially during teeth development in the pre-eruptive stage. Paul continually avoids this as he also does the normal and natural role of fluoride in bioapatites.

Paul has not even acknowledged the citations I have given supporting this systemic function for fluoride. I guess all I can do is add another one – published this month – Cho, et al (2014). Systemic effect of water fluoridation on dental caries prevalence.

Paul’s concessions

I guess we should acknowledge there has been some progress during this exchange as Paul has made a few concessions. It is worth recording them here to show they have occurred – but of course I am interested to see if he still repeats his original claims elsewhere.

Fluoridated and unfluoridated data for the Irish Republic. Finally Paul seems to understand my point on this. At least he apologises and said he should have checked.

I really can’t understand why he was confused  for so long (I raised is in my first article) but we all have our moments, I guess. He should now understand that use of WHO and similar data showing improvement of oral health in both fluoridated and unfluoridated areas is not a proof that fluoridation is ineffective. This fallacy is repeated again and again by opponents of fluoridation and ignores completely the multiple issues involve in oral health. Scientifically literate people should not resort to such fallacies.

I will be interested to see if he avoids this fallacy in future. A sign of good faith would be for him to remove or amend the section on the FAN website which promotes this fallacy.

Xiang et al’s margin of safety calculation. I asked Paul several times to clarify this because he was using a figure of 1.9 ppm yet Xiang’s paper was completely silent on how the value was obtained and seems to ignore the large variability of the data –  another sign of poor reviewing by the journal Fluoride. Paul now seems to have walked away from reliance on Xiang et al (2003) and a threshold value of 1.9 ppm and wants to take a different approach.

But, he still wants to use the poor quality Chinese data and does nothing to justify using that data in the absence of demonstration of any causal, and not incidental, relationship between fluoride in drinking water and IQ. I think this makes his calculations meaningless.

In the meantime could he please remove the sections of his FAN website arguing for the 1.9 ppm margin of safety?

What happens when fluoridation is stopped. Paul has accepted my point that at least in the cases of the former DDR and La Salud, Cuba, the results are consistent with use of alternative fluoride sources such as fluoridated salt, mouth rinses and dental applications. While admitting I had a valid point he says:

“Ken responded that in two of these studies other measures were taken which might have explained why tooth decay did not increase. I in turn argued that that if this was the case it shows that there are alternatives to fluoridation that work.”

Two points.

No one claims there are no alternatives to fluoridated drinking water. I have pointed out again and again that there are. So why the red herring? Paul was citing these studies to “prove” fluoridation is ineffective and I showed his conclusions were not justified.

Paul appears desperate to cling to any case I have not looked at. Must I go through every example and look at the details? Can he not do this himself? If there are no mitigating circumstances this would surely support the argument he wants to make. We should not do science this way. We should always approach the literature and research critically and intelligently.

Having conceded on La Salud and the former DDR is he prepared to modify his claims about these situations in his FAN website?

National Fluoridation Information Service

Some discussion of this body is important as Paul’s confusion extends a lot further than its name. He is demonstrating how he cynically uses terms like “weight of evidence analysis.” Cynical because he rejects the very body (NFIS) that is taking this scientific approach in New Zealand and throws his advocacy behind the body which is biased, uncritical and unintelligent in considering the evidence. The body which cherry-picks literature and interprets it selectivity to support its confirmation bias. He supports the NZ Fluoridation information Service (NZFIS).

As I wrote in my last article the NZFIS is an astroturf organisations set up by the FANNZ. Paul well knows that FANNZ has a clear bias and political aims with a declared purpose of “bringing about the permanent end to public water fluoridation (“fluoridation”) in New Zealand,” (quote from FANNZ rules).

Simple consideration of the NZFIS web site shows that it does no active work on the fluoridation issue. It’s material is old, biased and there is no current activity. However, the organisation is used for distributing biased press releases and attempting to claim scientific credibility. (See, for example, my recent article False balance and straw clutching on fluoridation.)

I can understand why Paul throws his support behind FANNZ and the NZFIS. They are part of the international tentacles of his organisation FAN. This is not about science or “weight of evidence analysis” at all. It’s about political activism.

So of course Paul must bad-mouth the organisation which is doing the work and taking a scientific approach in NZ – the National Fluoridation Information Service (NFIS). He says:

“My concern here is the use of taxpayer money (about 1 million dollars) to support the promotion of fluoridation rather than presenting a balanced view of the evidence.”

Well he would say that wouldn’t he? He treats public funding of NZFIS as a smear! That is the typical naive conspiracy theory approach taken by climate change deniers and any other anti-science organisation who attempt to discredit scientific findings. It distorts the facts completely – governments don’t employ scientists to produce a predetermined conclusion – if they wanted that theologians would be more appropriate and a lot cheaper. Research funding is not used to confirm a bias but to employ the people and resources who can answer important questions.

He also seems to think dropping a figure like “about 1 million dollars” acts as a smear. Let’s put this into context – here is the NFIS budget for 2012/2013. From the 2012-2013 annual plan.


And, no, the NFIS does not spend its time issuing misleading press releases or providing institutional status to political activists. Here is how an early evaluation document described its role:

“NFIS is an information and advisory service which will support District Health Boards and Territorial Local Authorities by providing robust and independent scientific and technical information, advice and critical commentary around water fluoridation.”

Go to the NFIS website and have a look at its output – it is professional and balanced. It is a laugh to even compare the barely operating astroturf NZFIS with it. Of course Paul wants to discredit the NFIS – he would like our scientists and health professional to rely on his own biased political organisations instead.

My criticism of FAN

Paul says that in making criticisms of FAN I am playing a “pro-fluoridation activist rather than a scientist.” I disagree because scientists must be concerned about the quality of material they consider. The must be aware of ideologically driven cherry-picking, opportunist use of selected research and the promulgation of unwarranted conclusions being promoted for political or ideological reasons. This is all part of looking at all the evidence critically and intelligently.

Scientists are concerned about poor quality and misinterpretation. It is disingenuous of Paul to make an accusation of activism to ignore or deny, the legitimacy of these concerns.

Paul claims that even if “FAN is a terrible organisation .  . . That does not affect the scientific case for and against fluoridation.” I agree – the scientific case rests on objective reality and the science itself – not on reputation or rumour. But the determination and presentation of a case is very much influenced by the bias and the ideological and political positions of an organisation making the case.

In my last article I analysed the way that FAN worked to demonstrate why their information and claims are unreliable. I believe that was perfectly justified from a scientific perspective.

Similarly I think my arguments above analysing Paul’s mechanical interpretation of “weight of evidence,” and what he means by it in practice, are also justified from a scientific perspective.

Surely such analyses must be part of the critical  and intelligent consideration of the arguments of organisations and people? Isn’t this what Carl Sagan meant with:

“Skeptical scrutiny is the means, in both science and religion, by which deep thoughts can be winnowed from deep nonsense.”

Concluding message

Several times I have stressed my motivations in this debate are scientific and not supporting a specific policy. I am concerned at the way the scientific literature and findings are being misrepresented by ideologically driven activists. We have seen this before on issues like evolutionary science and climate change. Similar misrepresentation is currently rife among advocates of alternative and natural medicine and health. I believe it must be opposed.

Hopefully many readers have taken my point on this. While I currently believe fluoridation of drinking water is a worthwhile social policy in New Zealand I don’t see it as the end of the world if it is rejected by a community. Nor do I see it as the only way of overcoming deficient levels of fluoride in our diet. And, of course, there is always the possibility that future research may change the current scientific consensus that fluoride at the levels used in water or salt fluoridation is safe and beneficial. Science is like that. Because our knowledge is always provisional, but improving over time, we sometimes do modify our conclusions.

So, if readers take my point about the need to overcome misrepresentation of science in these sorts of issues I will consider participation in this exchange worthwhile – even if most readers do not change their political views on support or opposition to fluoridation of water.


Balls, M., Amcoff, P., Bremer, S., Casati, S., Coecke, S., Clothier, R., … Zuang, V. (2006). The principles of weight of evidence validation of test methods and testing strategies. The report and recommendations of ECVAM workshop 58. Alternatives to laboratory animals : ATLA, 34(6), 603–20.

Blakey, K. et al (2014). Is fluoride a risk factor for bone cancer? Small area analysis of osteosarcoma and Ewing sarcoma diagnosed among 0-49-year-olds in Great Britain, 1980-2005. International Journal of Epidemiology, 2014, January 14.

Cho, H.-J., Jin, B.-H., Park, D.-Y., Jung, S.-H., Lee, H.-S., Paik, D.-I., & Bae, K.-H. (2014). Systemic effect of water fluoridation on dental caries prevalence. Community dentistry and oral epidemiology.

Choi, A. L., Sun, G., Zhang, Y., & Grandjean, P. (2012). Developmental fluoride neurotoxicity: A systematic review and meta-analysis. Environmental Health Perspectives, 120(10), 1362–1368.

Colquhoun, J. (1987). Education and fluoridation in New Zealand: an historical study. Ph.D. thesis. University of Auckland, New Zealand.

Colquhoun, J. (1997). Why I changed my mind about fluoridation. Perspectives in Biology & Medicine, 41(1):29-44.

Colquhoun, J.; Mann, R. (1986). The Hastings fluoridation experiment: Science or swindle? Resurgence & Ecologist, 16(6), 243–248.

Colquhoun, J., & Wilson, B. (1999). The lost control and other mysteries: Further revelations on New Zealand’s fluoridation trial. Accountability in Research, 6(4), 373–394.

Comber, H., Deady, S., Montgomery, E., & Gavin, A. (2011). Drinking water fluoridation and osteosarcoma incidence on the island of Ireland. Cancer causes & control : CCC, 22(6), 919–24.

Diesendorf M. (1986) The mystery of declining tooth decay. Nature 322 125-129.

Domellöf, M., Lönnerdal, B., Dewey, K. G., Cohen, R. J., & Hernell, O. (2004). Iron, zinc, and copper concentrations in breast milk are independent of maternal mineral status. The American journal of clinical nutrition, 79(1), 111–5.

Healy, W.B.; Ludwig, T.G.; Losee, F. L. (1961). Soils and dental caries in Hawke’s Bay, New Zealand. Soil Science, 92(6), 359–366.

Kodama, H. (2004). Trace Element Deficiency in Infants and Children — Clinical practice. Journal of the Japan Medical Association, 47(8), 376–381.

Levy, M., & Leclerc, B.-S. (2012). Fluoride in drinking water and osteosarcoma incidence rates in the continental United States among children and adolescents. Cancer Epidemiology, 36(2), e83–e88.

Ludwig, T. G. (1958). The Hastings Fluoridation project I. Dental effects between 1954 and 1957. New Zealand Dental Journal, 54, 165–172.

Ludwig, T. G. (1959). The Hastings fluoridation project: II. Dental effects between 1954 and 1959. New Zealand Dental Journal, 55, 176–179.

Ludwig, T. G. (1962). The Hastings fluoridation project III-Dental effects between 1954 and 1961. New Zealand Dental Journal, 58, 22–24.

Ludwig, T. . (1963). Recent marine soils and resistance to dental caries . Australian Dental Journal, 109–113.

Ludwig, T. G. (1965). The Hastings fluoridation project V- Dental effects between 1954 and 1964. New Zealand Dental Journal, 61, 175–179.

Ludwig, T. G. (1971). Hastings fluoridation project VI-Dental effects between 1954 and 1970. New Zealand Dental Journal, 67, 155–160.

Ludwig, T. G.; Healy, W. B.; Losee, F. L. (1960). An association between dental caries and certain soil conditions in New Zealand. Nature, 4726, 695–696.

Ludwig, T.G.; Healy, W. B. (1962). The production and composition of vegetables in home gardens at Napier and Hastings. New Zealand Dental Journal, 58, 229–233.

Ludwig, T.G.; Pearce, E. I. F. (1963). The Hastings fluoridation project IV – Dental effects between 1954 and 1963. New Zealand Dental Journal, 59, 298–301.

NFIS (2013) Community Water Fluoridation and Osteosarcoma – Evidence from Cancer Registries. (2013), (May).

NFIS (2013) A review of recent literature on potential effects of CWF programmes on neurological development and IQ attainment.

Scientific Committee on Health and Environmental Risks SCHER (2010).  Critical review of any new evidence on the hazard profile , health effects , and human exposure to fluoride and the fluoridating agents of drinking water.

Xiang, Q; Liang, Y; Chen, L; Wang, C; Chen, B; Chen, X; Zhouc, M. (2003). Effect of fluoride in drinking water on children’s intelligence. Fluoride, 36(2), 84–94.

The links to all the articles in the exchange are listed by date on the Fluoride Debate page. I will shortly  put the articles together in a PDF document (and maybe an eBook format) so readers can download and consult at their leisure. Maybe we could even use Paul Connett’s speaking tour of New Zealand early in the year to encourage people to read the exchange.

Thanks to Paul Connett for agreeing to this exchange (it was actually his idea to try it as an on-line exercise) and to all the people who participated in the comments discussion.

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Fluoride debate: Paul Connett’s Closing statement

Yes, this is the absolute, guaranteed, final statement from Paul Connett in this exchange. It responds to Ken Perrott’s last article Fluoride debate: Ken Perrott’s closing response to Paul Connett?

For Paul Connett’s original article see – Fluoride debate Part 1: Connett.

A final attempt to bring this debate back to science.

The structure of this posting.

 Part A.  A few introductory comments

 Part B.  Ken’s claim that the Hastings trial was not “fraud” but bad science

 Part C.  Major issues that have been avoided or poorly addressed

  1. The difference between concentration and dose
  2. The need for a Weight of Evidence analysis – especially on fluoride’s impact on the brain
  3. The need for a Margin of Safety Analysis when harm has been found at a certain level
  4. A margin of safety analysis for lowered IQ
  5. Bottle-fed babies: a special case
  6. Osteosarcoma: politics versus science

PART D. A response to some of the issues raised in Ken’s last posting Ken Perrott’s closing response to Paul Connett? December 30, 2013  not covered in Parts A-C.

 PART E.  A Summary of the key arguments against fluoridation

 PART A. Introductory comments

 A.1) Attacking the messenger instead of dealing with the message

 A lot of time was wasted in Ken’s final posting  Ken Perrott’s closing response to Paul Connett? December 30, 2013  in attacking the Fluoride Action Network, FAN-NZ and other opponents of fluoridation.  In my view, Ken would have served his pro-fluoridation position better by providing solid scientific references to support the proponents’ claims of effectiveness and safety. I address some of the specific issues he raises in part D below.

A.2) There are some important unresolved issues, which I have raised in earlier posts but not fully addressed by Ken. I will cover these in Part C.


 B.1 The Hastings-Napier Fluoridation Trial Fraud

Let me summarize the bare bones of the issue here.

The Hastings Napier trial was meant to have Hastings as the fluoridated community and Napier as the control. In other words it was going to be cross-sectional study – comparing tooth decay in two cities at the same point in time after one had been fluoridated and the other had not. Shortly into the experiment the control city was dropped, thus the study became a longitudinal one. In this case comparing the tooth decay in one city (Hastings) at the beginning and end of the trial.

For such a comparison to be valid, there must be no change in key parameters during the trial. However, there was a change in one of the key parameters in this trial and it was a major parameter – the method of diagnosing and treating tooth decay. This was less stringent at the end than it was at the beginning. Thus the drop in tooth decay attributed to fluoridation was part, or all, the result of making the diagnosis and treatment of tooth decay less stringent.

What convinces me the final report was a fraud was that the authors did not mention the change in diagnosis when claiming the drop in tooth decay was due to fluoridation. In my view this was more than an oversight or just “bad science” as Ken argues.  As this trial was used to promote fluoridation throughout NZ it is a very serious matter indeed.

Ken makes three points that do not pertain to the central fraud discussed above and completely ignores the “smoking gun” letter from NZ Dental Director G.H. Leslie.

First, Ken says that the method of changing the diagnosis of tooth decay was applied throughout NZ and not just locally. Ken argues:

“My own family remembers this change in dental technique by the school dental service because it was country-wide – not restricted to Hastings as Colquhoun, and Paul, imply. There goes the conspiracy theory and Paul’s claim of a scientific fraud.”

No it doesn’t. Whether the diagnosis and treatment of tooth decay was changed locally or nationally, the authors of the report should have acknowledged this very important change in their report. Their failure to do so – and claiming that their study showed that fluoridation was a great success – was a fraud.  What legitimate researchers should have done was to instruct the nurses not to change the way teeth were treated in Hastings (regardless of what was happening in the rest of NZ). In this way they could have maintained the same situation with this key parameter at the beginning and the end of the trial. But they didn’t.

Ken’s second point was to argue about why the control city was dropped. However, whether the control city was dropped for bogus or legitimate reasons the central charge remains the same. The resulting longitudinal study in Hastings was a fraud because of the fundamental change that was made and not announced by the authors.

Ken’s third point is his citation of paper by Akers (2008) to convince us that it wasn’t a swindle but bad science.  But Akers’ comment is certainly not a rebuttal, if anything it is a confirmation.

Here is the quote from Akers:

 “The changing of NZSDS [NZ School Dental Service] diagnostic criteria for caries and the cessation of the NZSDS nurses’ practice of prophylactic restoration of fissures further confused interpretations. While later antifluoridationists justifiably claimed that the changed diagnostic criteria contributed to the fall in caries (Colquhoun, 1999), their “science or swindle” questioning of methodology and findings (Colquhoun and Mann, 1986; Colquhoun, 1998; Colquhoun and Wilson, 1999) simplified confounding variables and dismissed international evidence supporting community water fluoridation as one factor in declining community caries incidence (de Liefde, 1998).”

 Readers will note that Akers does not claim that the diagnostic wasn’t changed. He admits that it was and he acknowledges that, “antifluoridationists justifiably claimed that the changed diagnostic criteria contributed to the fall in caries”

Whether there were other confounding factors not acknowledged by Colquhoun, the charge of fraud centers around the important change in diagnostic that was not acknowledged by the authors of the report.

Ken also ignored the incriminating evidence presented in the letter from G.H. Leslie, the Director of Dental Health for NZ that I quoted in my previous post.

There is no doubt about the validity of this letter. This “smoking gun” letter was obtained by Colquhoun who used the Official Information Act 1982 to obtain all the files pertaining to the Hastings-Napier trial from Department of Health files (1951-1973) now held in National Archives, Wellington. This letter from Leslie was found in those files and was reprinted in the paper by Colquhoun and Wilson (1990).

Here is the letter again:

                                                                                  12, October 1962

Mr. Swann,                                                  

 I have delayed acknowledging receipt of Dr. Roche’s letter to you and replying to your minute in the hope that I would by now be able to give a positive reply to your enquiry. I still cannot.

No one is more conscious than I am of the need for proof of the value of fluoridation in terms of reduced treatment. It is something which has been concerning me for a long time. It is only a matter of time before I will be asked questions and I must have an answer with meaning to a layman or I am going to be embarrassed and so is everyone else connected with fluoridation. But it is not easy to get. On the contrary it is proving extremely difficult. Mr. Espia is conferring with Mr. Bock and Mr. Ludwig and I am hopeful that in due course they will be able to make a practical suggestion.

 I will certainly not rest easily until a simple method has been devised to prove the equation fluoridation = less fillings

 (G.H. Leslie)


Division of Dental Health 

According to Colquhoun and Wilson (1990) what was concerning Leslie in 1962 (which was 8 years into the 10-year Hastings trial) was that the Hastings tooth decay statistics showed little difference between those exposed to fluoridation in Hastings and the rest of unfluoridated New Zealand. In other words, fluoridation wasn’t working.

Miraculously, two years after this letter was written, the Fluoridation Trial report showed that the Hastings trial was a great success!

In conclusion, I can find no evidence of a published rebuttal of the conclusion that this Hastings trial amounted to fraud. Certainly Colquhoun’s co-author Professor Robert Mann is not aware of one and I have checked with him.

PART C: Elaboration of some key issues so far not satisfactorily resolved

 C.1) The difference between concentration and dose

In our exchanges Ken has never commented on the key difference between concentration (mg/liter) and dose (mg/day). This question is important because leading proponents, organizations and agencies that promote or defend fluoridation often blur this key distinction in a self-serving manner.

For example, the American Dental Association (ADA) denied the relevance of the National Research Council’s groundbreaking review on the toxicology of fluoride in drinking water (NRC, 2006), to water fluoridation – on the day it was published – because they argued that the NRC panel only found harm in the range of 2 – 4 ppm and in the U.S. we fluoridate in the range of 0.7 – 1.2 ppm. The Oral Health Division of the Centers for Disease Control and Prevention (CDC) made similar claims six days later as did the Australian Government’s NHMRC Report in 2007.

One of several things wrong with this argument by the ADA, CDC and NHMRC is that above-average water drinkers in communities with 0.7 – 1.2 ppm could easily get higher doses than some of the below-average water drinkers in the communities at 2 ppm and even 4 ppm. In short, the concentrations may be different but the doses overlap – and it is the dose that can cause harm.

Fluoridation proponents continue to make the same claims today when they argue that we can ignore the studies that have found a lowering of IQ associated with fluoride exposure (Choi et al, 2012) because they were carried out at higher concentrations than the levels we use in water fluoridation programs.  The weaknesses of such arguments will become clear in my margin of safety analysis based on 5 of the studies in the Choi review below.

C.2) The need for a “weight of evidence” analysis – especially on fluoride’s impact on the brain.

 In toxicology we seldom have a definitive study about the risks or safety of a particular substance sufficient to resolve a dispute to everyone’s satisfaction, especially to the satisfaction of those with special interests. That is why some bodies favor the application of the Precautionary Principl, (Tickner and Coffin, 2006) into which we go into in some detail in chapter 21 of The Case Against Fluoride… .

Less controversially many regulatory agencies settle for a “weight of evidence” analysis where they carefully balance all the studies – including both human and animal, as well as epidemiological, clinical, and biochemical – before they conclude one way or the other whether a particular chemical is going to cause harm to any specific population.

I have provided a list of studies on the brain from which the “weight of evidence” suggests that fluoride is a neurotoxin and could well be lowering the IQ of children.  Ken has yet to produce any studies that would outweigh this conclusion. Here is that list again:

In over 100 animal studies that we have examined, at least 40  show that prolonged exposure to fluoride can damage the brain

 At least 19 animal studies report that mice or rats ingesting fluoride have an impaired capacity to learn and remember

 At least 12 studies (7 human, 5 animal) link fluoride with neurobehavioral deficits

 3 human studies link fluoride exposure with impaired fetal brain development, and we are not aware of any that don’t

 37 out of 43 published studies show that fluoride lowers IQ, of which 27 were part of a meta-analysis conducted by a team from Harvard (Choi et al. 2012)

The full citations to all these studies can be accessed at www.fluoridealert.org/issues/health/brain

With respect to the lowering of IQ several of the studies are strengthened by the fact that the lowering of IQ was inversely related to urine fluoride levels (Xiang et al., 2003 and Ding et al, 2011). In addition, Xiang et al (2011) showed that the lowering of IQ was inversely related to plasma fluoride levels. In other words the lowering of IQ can be related to individual exposure to fluoride.

The NRC (2006) report had a whole chapter on this matter and so do we, in The Case Against Fluoride…,  but the proponents of fluoridation have done their level best to ignore, downplay or distract attention from this landmark NRC review as well as the updated discussion in our book, and most recently the systematic review by Choi et al (2012).

As far as the IQ studies are concerned, at the time the NRC (2006) reviewed the matter there were only five IQ papers available to them. Even so, the NRC panel – while pointing out some weaknesses in these studies – commented on the consistency of the results and recommended more research. But none has been published in the U.S. or any other fluoridated country in the 7 years plus since the NRC recommendation was made.

Thanks to translations made available by the Fluoride Action Network of studies previously published in China, and several new studies from Mexico, Iran and India, there are now 43 IQ studies available. 37 of these indicate a statistically significant lowering of IQ associated with fluoride exposure. The Harvard team reviewed 27 of these studies (Choi et al, 2012) and found a lowering of IQ in 26 studies, with an average lowering of about 7 IQ points.

Ken is rightfully concerned about the well-being of children from low-income families, but is he willing to put the questionable benefit from fluoridation above the possibility of harm to their neurological and mental development? Especially when other countries have achieved success with alternative approaches. Why force whole populations –especially low-income families who cannot afford avoidance measures – to take such risks?

C.3) The need for a “Margin of Safety” Analysis when harm has been found at a certain level

This analysis is critical when you are considering rejecting the relevance of a study based on the dose levels used, or concentrations in the case of fluoridation proponents.

It is important to remember that in any large population we can anticipate a very large range of sensitivity to any toxic substance. Like most other human traits such sensitivity follows a normal distribution curve (the famous bell-shaped curve). Most people cluster around the average  – the bulge of the bell – and will have an average response but at the tails of this curve – the lips of the bell – we will have people who are very sensitive at one end and very resistant at the other. Typically toxicologists assume some people are going to be at least 10 times more sensitive than the average person. This is used to generate a default safety factor of 10 (sometimes referred to as the “intra-species variation” safety factor). This default value is only dropped to a smaller value than 10 if the population in the study group is very large.

Thus if we find harm in a small human study and wish to determine the level that would protect everyone in a large population from that harm this is what we do. We take the dose (mg/day), which has been found to cause no harm (the so-called no observable adverse effect level or NOAEL) and divide that dose by 10 to give a safe dose for the most sensitive individual in the population. Frequently we don’t have a NOAEL and so we have to use a LOAEL (the lowest observable adverse effect level) and divide that by 100. Sometimes this process is corrupted and it is the LOAEL not the NOAEL that is divided by 10. The method used by Xiang (2003 a) is a variant on this method, but it usually arrives at similar end points.  It uses all the data in a study to find the dose-response curve, not just the NOAEL and LOAEL.

Applying these calculations in a real world situation is called a Margin of Safety Analysis and shockingly it is very seldom considered by people who promote fluoridation. They simply use the very crude and highly misleading approach of comparing the concentration used in the study group with the concentration of the fluoride in the water of the fluoridated population, as discussed above in C.1.

C.4 A margin of safety analysis for lowered IQ

Ken has reasonably questioned how Xiang determined the threshold value that I used in the Margin of Safety analysis in a previous posting. In rechecking Xiang’s explanation I find it is rather complicated, even though he appears to have used a methodology advocated by the US EPA. I have no problem with Ken raising this question but I do have a problem with the way he has used this one detail as a way of avoiding the main exercise.  That main exercise is how one goes about determining a safe dose for everyone in a large population when one has evidence that there is harm in a small study group.

I am going to repeat the margin of safety analysis for lowered IQ  without using Xiang’s threshold value of 1.9 ppm. Instead, I will start with the nine studies where IQ was lowered at a fluoride level less than 3 ppm.

Of these nine studies I have used five of the six where the result is  statistically significant . The sixth is a study by Lin et al (1991), which I have excluded because it is complicated by the iodine levels involved.  These five studies had levels where IQ was lowered in the high-fluoride village at 1.8; 2; 2.38; 2.5 and 2.9 ppm. See Table 1.



 Here is a step-by-step explanation of my margin of safety analysis.

 Step a) As our starting point I choose the study that found a lowering of IQ at the lowest concentration. That was 1.8 ppm.

 Step b) Our next task is to estimate the reasonable dose range this represents for the children in the study group – which of course, will depend on how much water they drink and how much they get from other sources. We assume (correctly, we believe) that very few of these rural Chinese children use fluoridated toothpaste and that their daily dose comes largely from the water.

  • If they drank 2 liters of water per day at 1.8 mg/liter  (i.e. 1.8 ppm) their daily dose would be (2 L x 1.8 mg/L) = 3.6 mg/day.
  • If they drank 1 liter of water per day their daily dose would be 1.8 mg/day
  • If they drank 0.5 liters of water per day their daily dose would be approx 0.9 mg/day.

In other words a reasonable estimate of the range of the dose leading to a lowered IQ was approximately 0.9 – 3.6 mg/day.

Step c) Our third task is to determine a safe dose to protect all the infants and children from lowered IQ in a large population.

From this range the LOAEL is 0.9 mg/day. We do not have a NOAEL so we have to divide the LOAEL by 10. So the NOAEL = 0.09mg/day.

To protect every child (including the most vulnerable) we have to divide the NOAEL by a further factor of 10. This is being very conservative, but it is the standard procedure unless one has data from a large population study.

Thus we would not want any child in a large population ingesting more than 0.009 mg/day of fluoride to protect against lowered IQ (NOAEL divided by 10). This translates into 9 ml of water fluoridated at 1 ppm . Here is the calculation. 9 ml = 0.009 Liters.  0.009 L x 1 mg/L = 0.009 mg/day

Of course this is a rather crude measure because the subjects in this study were children, whose weight (and hence perhaps tolerance of fluoride) varies according to age and other factors. We shall refine this shortly in relation to infants.

Conclusion. Based upon the five statistically significant IQ studies that found a lowering of IQ at less than 3 ppm a responsible regulatory authority would not allow water fluoridation. Little wonder then that fluoridation promoters are doing everything they can to criticize these IQ studies.

Note: this is an analysis based on the data available. Of course there are things we don’t know which can affect the interpretation. For example we don’t know that post-natal fluoride consumption is the most important variable: it might be prenatal exposure.

C.5) Bottle-fed babies: a special case

Let me return to the issue that got me involved in this matter 17 years ago: the level of fluoride in mothers’ milk. I do not believe Ken has provided a convincing explanation as to why we should ignore this issue.

The level of fluoride in mothers’ milk is very low. For a woman in a non-fluoridated area it is about 0.004 ppm (NRC, 2006, p.40), although a range of values has been reported.

There are certain realities about the fluoride ion which make it incompatible for a lot of biochemistry – always given the important caveat of the concentration levels reached – and these are its ability to seek out positive centers like metal ions and hydrogen bonds – both critical for biochemical structure and function.

These fundamental attractions can easily explain fluoride’s known ability to inhibit enzymes, help to switch on G-proteins non-specifically, and possibly cause oxidative stress. These interactions are so fundamental that we should not be at all surprised if many ailments may be caused by fluoride. It was the American Medical Association (before fluoridation began) that used old-fashioned terminology when it stated that fluoride was a “general protoplasmic poison” in its warning not to rush into water fluoridation in a 1943 editorial in JAMA.

So let us briefly extend the margin of safety analysis to bottle-fed babies.

Here we have to take into account the extra problem of the baby’s small bodyweight.  To take bodyweight into account we use a different measure of exposure: i.e. dosage instead of dose.

Dose is measured in mg/day, dosage is measured in mg/kilogram bodyweight/day.

If we consider that the ‘safe’ dose we have determined (0.009 mg/day) and apply that to 20 kg child, then we would say the safe dosage was 0.00045 mg/kg/day (0.009 mg/day divided by 20 kg). Then the safe dose for a 7 kg baby would be 0.00315 mg/day. (7 kg x 0.00045 mg/kg/day = 0.00315 mg/day).

A breast fed baby (with mothers milk at 0.004 ppm) drinking 800 ml a day would get 0.004 mg/L x 0.8 L = 0.0032 mg/day which is very close to the level we have determined is safe. So based on these calculations, the fluoride that naturally occurs in breast milk does not pose a risk of lowering the IQ in babies.

A bottle-fed baby (with water at 0.7 ppm) drinking 800 ml a day would get 0.7 mg/L x 0.8 Liters = 0.56 mg/day. This is 0.56/0.00315 = approx 180 times higher than the safe level to protect against lower IQ.

A bottle-fed baby (with water at 1.2 ppm) drinking 800 ml a day would get 1.2 mg/L x 0.8 Liters = 0.96 mg/day. This is 0.96/0.00315 = approx 300 times higher than the safe level to protect against lower IQ.

So whether by accident or by evolutionary “design” mothers’ milk is protective against lowered IQ but formula made up with fluoridated water (0.7-1.2 ppm) is not. The latter delivers a daily dose of fluoride, that is a factor of 180-300 times too high for a 7 kg baby.

C.6) Osteosarcoma: politics versus science

This is another issue to which Ken has not responded. It also one of the 10 “Ugly Facts,” which I feel should have ended the fluoridation experiment. This ugly fact occurred in 2001 when Elise Bassin, a dentist completing her doctoral thesis at the Harvard Dental School, found in a carefully conducted matched case-control study, that young boys exposed to fluoridated water (at 1 ppm) in their 6th to 8th years had an associated 5-7 fold increased risk of succumbing to osteosarcoma. Osteosarcoma is a rare but frequently fatal bone cancer.

Her study was first hidden (politics) from the public and scientific community, but was eventually published in 2006. Despite published promises from her thesis adviser that his larger study would refute her finding (politics), his study when it was finally published in 2011 entirely failed to do so (Kim et al., 2011).

So what we have here is an unrefuted study that indicates that a few young boys may be losing their lives by drinking fluoridated water.  I am really amazed that promoters of fluoridation can take this issue so lightly. The small number involved should not justify turning a blind eye to this. As John Colquhoun asked in my videotaped interview with him in 1997 how much tooth decay saved would be an adequate exchange for “one death of a teenage boy from osteosarcomahttp://fluoridealert.org/fan-tv/colquhoun/

I am also disturbed that the Pew Charitable Trusts (a multibillion dollar foundation that is actively campaigning in support of fluoridation) would mischievously claim that the Kim et al (2011) study has put the matter to rest when it clearly has not.

The issue of fluoride and osteosarcoma has a long and fascinating history. There is a lot of politics involved, which is not surprising because if this connection was proven it would spell the end of fluoridation. We go into this sixty year history in some detail in Chapter 18 of our book, The Case Against Fluoride…  A timeline can be found on the FAN website at http://fluoridealert.org/studies/cancer05/ where full citations of the references can be found. Space forbids including it all here so we will jump to 2001.

2001. Even though Bassin’s thesis advisor Professor Chester Douglass had signed off on her thesis, in the three years that elapsed after her research was successfully defended he did not inform his peers, the NRC panel or his funders of this dramatic finding (politics). Instead he kept insisting when asked that his “own” study found no relation between osteosarcoma and fluoridation, without indicating that his own graduate student had found the opposite to be the case (and with better methodology).

Douglass knew of course that if this connection between fluoridation and osteosarcoma was established it would end fluoridation, and stated as much in a paper he had co-authored ten years earlier (McGuire et al.,1991).

2005. Eventually Bassin’s doctoral thesis was found in one of the Harvard libraries in 2005.  The Environmental Working Group charged Douglass with academic misconduct for hiding this finding and asked the NIH (which had funded the study) to investigate.  The investigation was handed over to Harvard. A committee appointed by the Harvard Dental and Medical Schools investigated the matter and in a short 4-paragraph statement exonerated Douglass, finding that he did not “deliberately” hide these findings. Harvard refused repeated requests for them to provide the basis for this decision.

2006. Bassin’s findings were finally published in the journal Cancer Causes and Control (Bassin et al., 2006). In the same issue of the journal a letter was published from Douglass that stated that his larger study would show that Bassin’s thesis did not hold (Douglass and Joshipura, 2006). Douglass told the NRC panel that this larger study would be available in the Summer, 2006. But it did not appear for five years.

Meanwhile, Douglass’ promise of a study in a letter was used by the NHMRC (2007); Health Canada (2011) and health authorities in the UK as if it was an actual peer-reviewed and published study (more politics).

2011. Eventually the Douglass paper was published in 2011, but oddly enough not in a cancer journal but in a dental journal, although it had nothing to do with teeth (Kim et al., 2011). The study has many weaknesses, but the key fact is that it did not refute Bassin’s findings. Nor could it possibly do so. Because the biometric of exposure was the accumulated fluoride levels in the bones. As the authors themselves admitted, there is no way such levels could be used to determine the exposure to fluoride during the critical age window of vulnerability found by Bassin (the 6th to 8th years).

Conclusion: a well-researched study found a possible relationship between exposure to fluoridated water – at a specific age range in young boys – and a rare but frequently fatal bone cancer. Despite promises to the contrary, which were greedily gobbled up and repeated ad nauseam by promoters and supporters of fluoridation, this study has never been refuted.

It may be that fluoridation is killing a few – not many – young boys each year from this cancer. This is not fearmongering on my part. It is the current state of affairs as far as legitimate scientific research is concerned.

As with the lowering of IQ we are talking about serious albeit unproven risks here. When even prominent promoters of fluoridation have acknowledged that the predominant benefit of fluoride is topical and not systemic (CDC, 1999 and 2001), it remains puzzling – at least from a scientific point of view – why promoters are willing to take these risks.  Especially, when it is clear that tooth decay is being reduced in the vast majority of countries that fluoridate neither their water, nor their salt, nor their milk.

There are alternatives, including education on dental hygiene, education for better diets (especially pregnant women and young children) and targeted topical treatments for the most vulnerable populations as currently being practiced in Scotland.

Part D

 Here I address some of the issues presented in Ken’s Final Posting Ken Perrott’s closing response to Paul Connett? December 30, 2013  not covered in Parts A-C.

 Ken’s comments are in bold and blue.

D.1) Correcting some misrepresentations 

This is Ken’s title for a super-gish-gallop of complaints and accusations, some trivial, some contentious, some correct and a few that raise important issues. Some deserve or require response. It seems rather a pity to end the exchange, which in some ways has been interesting and informative on such a ding-dong and largely negative note. I shall try to conclude with something a bit more positive.

D.2)…I would be perfectly happy to see New Zealand switch to fluoridated salt.

Certainly fluoridated salt would be an improvement over fluoridated water because it would give citizens a choice on whether they wanted to increase their ingestion of fluoride or not

D.3) “Maybe the most empathetic solution is that society as a whole compensate this small number of people [who have increased sensitivity to fluoride, PC] in some way to aid them with their predicament.”

I am sure that those with this predicament are grateful for Ken’s empathy but probably believe, like I do, that the chances of the NZ government compensating them for a condition it does not recognize and is not willing to study is next to nil. So perhaps he might agree that  a better way to relieve their symptoms would be simply to stop fluoridating the water.

D.4) Paul criticises public funding of an information service in New Zealand set up specifically to facilitate a “weighted evidence approach” towards fluoridation research.

My concern here is the use of taxpayer money (about 1 million dollars) to support the promotion of fluoridation rather than presenting a balanced view of the evidence. Yes, I was confused by the similar names; my mistake.

The citizens of NZ have reason to be grateful that a counterbalancing site has been set up. Its mission statement is worth reading because it clarifies why it came into being and how the organizers perceive their role:

“The New Zealand Fluoridation Information Service has evolved from frustration that useful, factual information about fluoridation has become almost impossible for the public and even professionals to sort out. NZFIS’ main goal is to facilitate full public and scientific examination of this public policy, which has become obscured by biased or inept media treatment (or lack thereof), by political rhetoric, and because of the obfuscation surrounding important information.

Probably the best that independent people can do, who are interested in this controversial issue, is to read the material on both sites and make their own judgment.

D.5) Paul is still confused about the graphic I introduced early in this exchange showing data for fluoridated and unfluoridated areas of the Irish Republic.

My apologies. I should have checked back.

D.6) He (Paul) has already lost that argument (about fluoridation cessation studies not leading to increased tooth decay) and he is desperately clutching at his remaining straws…

I have acknowledged that Ken had raised some valid arguments pertaining to the effects of ending water fluoridation but he takes this a little too far. Here is the background: proponents have argued that ending fluoridation would be a disaster as far as tooth decay was concerned. We have cited four modern studies that indicate that tooth decay did not increase when fluoridation was halted in Cuba, former East Germany, Finland and British Columbia, Canada.

Ken responded that in two of these studies other measures were taken which might have explained why tooth decay did not increase. I in turn argued that if this was the case it shows that there are alternatives to fluoridation that work, removing the need to force this practice on people who don’t want it.

In checking one of the other studies from British Columbia (Maupomé et al, 2001 and Clark et al, 2006) I came across a study commissioned by the City of Toronto Public Health Board. This study examined the very issue of what would happen if fluoridation was ceased in Toronto (Azarpazhooh, 2006) and in the process carefully examined all the cessation studies available at that time. I think you can gauge from the fact that this pro-fluoridation board would not publicly release this report, that the results were not favorable to a pro-fluoridation position. After a great deal of effort the group Canadians Opposed to Fluoridation finally obtained this report and it can be accessed from their site.


D.7) He (Paul) again avoids the importance of including social good in ethical considerations of social health policies like fluoridation.

 I have no problem with entertaining the idea that a social good may over-ride individual preference (e.g. seat belts are a good example, and so is smoking in public). But I do not think that this notion applies in the case of water fluoridation. For those like Ken who believe it does, there are three hurdles in my view that they have to cross.

If they wish to force a practice on the whole population, against the express wishes of many, they at least need to demonstrate three things:

a) They must be sure that the good they are attempting to achieve is substantial and has been demonstrated with near certainty. We agree that no RCTs have been done to establish certainty and I think we may agree that the effect found in less rigorous studies has not, since the advent of fluoridated toothpaste, been all that impressive in absolute terms.

b) They must be sure that the good they are trying to achieve outweighs any harm that it may cause. In this case we have the undisputed increase in dental fluorosis, which can cause psychological harm when it reaches the moderate and severe levels, as well as being very costly to treat. In addition we have several distinct risks, which – largely due to a lack of will to seek evidence to corroborate or disprove them – should be seriously considered. These include impairment of brain development and IQ; long tem bone damage including some forms of arthritis; small increases in cancer deaths due to fluoride itself or arsenic contamination of the fluoridating chemicals; and (cf D3 above) production of sensitivity reactions in some individuals.

c) They can demonstrate that there are no other cost-effective approaches that can achieve the same aims (primarily the reduction of tooth decay among low-income families).  This is hard to demonstrate because many countries have achieved the same reduction in tooth decay without fluoridation. And I have also cited the targeted Scottish program, which appears cost-effective and has achieved remarkable results with the children of low-income families using fluoride only for topical application.

I think it is fair to say that none of the three hurdles has been cleared or even seriously attempted during this debate.

D.8) Paul’s emotional (or political) obsession with individual choice often comes though in the most unlikely places. Why should he use the term “forced fluoridation” in a polite scientific exchange?…. There is always a choice for those prepared to make the effort to satisfy their convictions.

Ken objects to the “impolite” word “forced” in connection with water fluoridation. Okay, someone like me, or like him I guess, living in a fluoridated community can install a reverse osmosis filter (expensive), avoid eating out or visiting friends (restrictive) and refrain from eating prepared foods (hmm). But let’s see what “forced” means to low-income families who are supposedly the main beneficiaries of the program. They can’t necessarily afford bottled water for drinking and cooking, and they can’t afford reverse osmosis units. They are trapped by this program. If these families do not share Ken’s belief that this program is doing them good, and may even be causing them harm, there is little they can do.

If these same families cannot afford bottled-water to make up baby formula, then they may be forced to give their babies about 200 times more fluoride than nature provides.  In this situation they are worse off than children from middle-income and higher-income families because fluoride’s toxic effects strike hardest on those with poor nutrition, low calcium, low protein, low vitamins and low or borderline iodine.

Let me introduce an idea about fairness into this discussion: the idea of “disproportionate imposition.” Clearly if you remove fluoride from the community’s water supply or add it, you are going to make some people happy and others unhappy. But let’s look at the “disproportionate imposition” involved here. For those who don’t want it – and it is added – they have to go at the least to the expense and inconvenience that I have discussed above . At the worst, they may be unable to avoid it at all.        In contrast, those who do want it – and it is removed from the public water supply – merely have to content themselves with fluoridated toothpaste, which they are probably using already – if they insist on ingesting fluoride they can drink fluoridated bottle-water or take sodium fluoride tablets.

I think the imposition to both sets of people is dramatically different. Thus at the very least – and on top of all the other arguments – this practice is unfair because of this disproportionate imposition factor. The idea that fluoridation is a social good is quite fallacious.

D.8) I am surprised Paul has taken the approach of blaming practically every illness or change on fluoride. 

I do not do this and we didn’t do it in our book. But it is a standard technique used by proponents of fluoridation. They ridicule the position of the opponents of fluoridation by claiming that we assert that every disease known to man is caused by fluoride. They sometimes include nymphomania, which is an invention entirely of their own making, to add to the ridicule.

Certainly there are some specific health concerns, most of which have been discussed at some length in this exchange. Those concerns deserve to be taken seriously because there are scientific reasons for postulating that fluoride may be involved in some way and to some extent in their pathogenesis. The case for investigating them is much enhanced by the fact that millions of people are having their total fluoride exposure increased by fluoridation.  Ken goes on to list these concerns, though he doesn’t really need to at this stage, but then he just dismisses them as a mere tactic of non-scientific activists!  Later he drags obesity into the discussion and his argument, if there is one, then becomes unintelligible to me. But let’s just look at the first on his list: arthritis.

Arthritis is of concern because the first symptoms of fluoride’s poisoning of the bone in endemic fluorosis areas are symptoms just like arthritis. We have argued that with arthritis reaching epidemic proportions in several fluoridated countries it would be a responsible thing for health agencies there to investigate whether there is any relationship between long-term exposure to fluoridated water and increased arthritis risk. It is not an unreasonable hypothesis. It is testable and one can reasonably argue that it should be tested. No fluoridated country has done so. I don’t think anyone is naïve enough to claim that all arthritis is associated with fluoride. Certainly I would never advocate anything so silly.

D.9) Paul insists on using the authority fallacy – out of context quotations from authoritative figures.

An example in his last article was that by David Locker. Perhaps he is not aware he is doing this – it seems to be an instinctive reaction for anti-fluoridation activists. He should appreciate that the world is never as simple as implied by such quotes. I see his resort to such fallacies as a weakness, not a strength.

I often quote the late David Locker. It is interesting that he, who has been pro-fluoridation reached a similar conclusion to my own, namely that today there seems to be not much of a significant benefit that can be associated with fluoridation (e.g. Brunelle and Carlos, 1990) or ingesting fluoride (e.g Warren et al., 2009).

For those who would like to see more of David Locker’s views on this subject I would encourage them to view a TV program featuring a three-way debate/discussion featuring David, myself and a representative of the Canadian Dental Association. The program (22 minutes in length) is a little rushed but still shows that you can have a civilized discussion on this with people who fundamentally disagree. http://fluoridealert.org/fan-tv/water-fluoridation-medical-hot-seat-debate/

I think David by occupying a middle position was key to the success of this program. Sadly he has since passed away at far too young an age.

It is ironic that Ken should complain about “anti-fluoridation activists” quoting authoritative figures because that strategy has been absolutely central to the promotion of fluoridation since the 1950s. They have used an endless list of endorsements from professional bodies, surgeon generals, Benjamin Spock, US Presidents  – you name it.  All this as a substitute for actual science!

D.10) Nature of Fluoride Action Network

If Ken wants to play pro-fluoridation activist rather than scientist, that’s fine by me.

He may convince himself and the rest of the world that FAN is a terrible organization, but that does not affect the scientific cases for and against fluoridation, which is what this debate is supposed to be about.

However I do urge readers, rather than taking Ken’s views of FAN at face value, to go to our homepage at (www.FluorideAlert.org) click on “researchers” top right, explore from there and draw their own conclusions.

PART E.  Summary: The Key Arguments Against Fluoridation

Based upon all the above I believe that my key arguments against fluoridation remain largely untouched. Here they are again.

E.1) Fluoride is not an essential nutrient. There is no need to swallow it or put it in the drinking water.

E.2) It is bad medical practice – you cannot control the dose or who gets the fluoride. It goes to everyone, for a lifetime with no individual monitoring for side effects or the accumulated dose in the bones.

E.3) It is an unethical practice – you are forcing fluoridation on people who don’t necessarily want it.

E.4) It is a reckless practice. It is reckless for several reasons but particularly because it involves giving bottle-fed babies about 200 times more fluoride than breast-fed babies.

E.5) The evidence that swallowing fluoride reduces tooth decaysignificantly in today’s conditions is weak. Ken failed to address the many epidemiological studies that I cited (and we discussed in our book in chapters 6-8), most of which were conducted by pro-fluoridation scientists or pro-fluoridation agencies, that suggested that very little absolute benefit comes from swallowing fluoride.  I singled out two studies. These were the studies by Brunelle and Carlos (1990) and Warren et al. (2009).

Both these studies were funded by the US taxpayer and both were conducted by pro-fluoridation researchers. So if there were any bias involved it would not have been in favor of the anti-fluoridation position. One study was very large and the other was small but very precise in its scope and nature.

Brunelle and Carlos (1990). This was the largest survey of tooth decay ever undertaken in the U.S. The teeth of 39,000 children from 84 communities were examined. The authors compared the Decayed Missing and Filled Surfaces (DMFS) for children who had always lived in a fluoridated community with children who had never lived in a fluoridated community. The average difference in tooth decay of the permanent teeth was 0.6 of one tooth surface and even this small saving was not shown to be statistically significant.

Warren et al., (2009). This study was part of the U.S. government funded “Iowa Study” where children’s tooth decay has been tracked from birth. The authors were attempting to find the so-called “optimal dose” needed by a child to reduce tooth decay. But they couldn’t find that dose. In fact, they could not find a clear relationship between tooth decay and the amount of fluoride ingested on a daily base. The authors concluded that, “These findings suggest that achieving a caries-free status may have relatively little to do with fluoride intake…”

E.6) Those countries in Europe that have opted not to fluoridate their water or their salt show little evidence that this decision has ruined their children’s teeth.

Ken argues that even though they don’t have fluoridated water, many use fluoridated salt and milk.  In actuality, the majority of European countries fluoridate neither their water nor their salt. The only country that still has even a small amount of fluoridated milk in a few schools is the UK. Bulgaria and a few other former-communist countries experimented with fluoridated milk, but it has never been given to more than a miniscule percentage of European kids.  Furthermore, with both fluoridated salt and fluoridated milk you are offering the individual a choice in the matter.

These countries have found alternative ways of fighting tooth decay, which do not involve forcing people to swallow fluoride who don’t want to. Those alternatives include early education for better dental hygiene, better diets, reduced sugar consumption, and targeted preventive measures (including topical treatments) for children from low-income families.

E.7) The admission by leading promoters of fluoridation like the CDC (1999, 2001) that the predominant action of fluoride is topical not systemic probably explains the findings in both E.5) and E.6) above.

E.8) There is a growing amount of evidence emerging that documents health effects at levels which offer no adequate margin of safety to protect everyone drinking fluoridated water, including the potential to lower IQ.

In the case study margin of safety analysis for lowered IQ (see C.4), I estimate that to protect every child drinking fluoridated water at 1 ppm, he or she should drink no more than 9 ml of water. The same analysis indicates that a breast fed baby is just about at the safe level to prevent lowered IQ, but a bottle fed baby will be getting 180 – 300 times above the safe level if its formula is made up with water at 0.7 and 1.2 ppm respectively (see C.6).

E.9) There is an unrefuted study that young boys drinking fluoridated water in their 6th to 8th years have an associated 5-7 fold increase of succumbing to osteosarcoma by the age of 20. As this rare bone cancer is frequently fatal, it is a shocking but real possibility that several young boys may be killed by this practice each year.

E.10) Since the U.S. Public Health Service endorsed water fluoridation in 1950 very little serious scientific attention has been directed into investigating both short and long term health effects of ingesting fluoride. Inexplicably the U.S. Food and Drug Administration has never regulated fluoride for ingestion and its official classification of fluoride is an “unapproved drug.” The U.S. National Research Council review of 2006 reveals many important but unanswered questions about ingested fluoride. The NRC also concluded that certain subsets of the population are exceeding the EPA’s reference dose for fluoride (the IRIS level) drinking water at 1 ppm fluoride; this includes bottle-fed infants and people with poor kidney function. The NRC recommended that the EPA Office of Water perform a new risk assessment to determine a new and safer MCLG (maximum contaminant level goal) for fluoride in drinking water. After nearly 8 years this new risk assessment has not been done. If determined honestly a new MCLG would almost certainly force an end to water fluoridation. Politics not science is keeping this practice afloat in the U.S.

Overall Conclusion. It is time to end water fluoridation worldwide. The very small and questionable benefits do not justify the huge risks being taken. New Zealand would be a good place to start the process. If it did so it would not make the U.S. health agencies that have doggedly promoted this practice for over 60 years very happy. However, NZ has shown itself capable of bucking the tide on other international issues in which the U.S. has held a strong contrary position. It would be refreshing for at least one fluoridating country to admit that it has made a mistake with this policy and set out to return scientific integrity to the center of its public health policies.

I thank Ken for sharing this debating platform with me. Of course we have disagreed on many things, which one would expect in any debate –but hopefully readers of all persuasions will have found enough to engage their interest.


Akers, HF (2008). “Collaboration, vision and reality: water fluoridation in New Zealand (1952-1968).” N Z Dent J. 104(4):127-33.

Azarpazhooh, A. (2006). Oral Health Consequences of the Cessation of Water Fluoridation in Toronto, MSc Thesis Report, Faculty of Dentistry – University of Toronto, City of Toronto Public Health. http://cof-cof.ca/2006/08/azarpazhooh-oral-health-consequences-of-the-cessation-of-water-fluoridation-in-toronto-msc-thesis-report-faculty-of-dentistry-university-of-toronto-city-of-toronto-public-health-2006/

CDC, 1999. Centers for Disease Control and Prevention, “Achievements in Public Health, 1900–1999: Fluoridation of Drinking Water to Prevent Dental Caries,” Mortality and Morbidity Weekly Review 48, no. 41 (October 22, 1999): 933–40, http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4841a1.htm

CDC, 2001. Centers for Disease Control and Prevention, “Recommendations for Using Fluoride to Prevent and Control Dental Caries in the United States,” Morbidity and Mortality Weekly Report 50, no. RR14 (August 17, 2001): 1–42, http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5014a1.htm

Choi AL, et al. (2012). « Developmental fluoride neurotoxicity: a systematic review and meta-analysis.” Environ Health Perspect 120:1362–1368.

Clark et al. (2006). “Changes In Dental Fluorosis Following The Cessation Of Water Fluoridation.” Community Dentistry And Oral Epidemiology, (2006) 34 197–204


Colquhoun J. and R. Mann (1986). “The Hastings Fluoridation Experiment: Science or Swindle?” The Ecologist 16, no. 6: 243–48.

Colquhoun, J (1987). Education and Fluoridation in New Zealand: An Historical Study,” Ph.D. diss., University of Auckland, New Zealand.

Colquhoun J. and B. Wilson (1999). “The Lost Control and Other Mysteries: Further Revelations on New Zealand’s Fluoridation Trial,” Accountability in Research 6, no. 4:373–94.

Connett, P., Beck, J and Micklem HS. The Case Against Fluoride. Chelsea Green, White River Junction, Vermont, 2010.

Ding Y, et al. (2011). “The relationships between low levels of urine fluoride on children’s intelligence, dental fluorosis in endemic fluorosis area in Hulunbuir, Inner Mongolia, China.” J Harzard Mat 186:1942-1946.

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Maupome´et al, (2001). “Patterns of Dental Caries Following the Cessation of Water Fluoridation.” Community Dentistry And Oral Epidemiology, 29 37–47


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Xiang, Q et al. (2003a) “Effect of Fluoride in Drinking Water on Children’s Intelligence,” Fluoride 36, no. 2 (2003): 84–94, http://www.fluorideresearch.org/362/files/FJ2003_v36_n2_p84-94.pdf

Xiang, Q et al.(2003b), “Blood Lead of Children in Wamiao-Xinhuai Intelligence Study” (letter), Fluoride 36, no. 3 (2003):198–99, http://www.fluorideresearch.org/363/files/FJ2003_v36_n3_p198-199.pdf

Xiang, Q et al. (2011). “Children’s serum F and intelligence scores in two villages in China.” Fluoride 44(4):191–194.

Anyone wanting to follow the debate and/or check back over previous articles in the debate can find the list of articles at Fluoride Debate.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page

Fluoride debate: Ken Perrott’s closing response to Paul Connett?

This is Ken Perrott’s response to Paul Connett’s last article Fluoride debate: Arguments Against Fluoridation Thread. Part 8. Paul.

For Paul Connett’s original article see – Fluoride debate Part 1: Connett.

This exchange is now winding down – despite the fact we have not dealt properly with all the items on Paul’s original list. The exchange has become repetitive and personal. I think readers are becoming bored with this and would have preferred us to work through each item in turn and move on. Paul’s declaration he “will end my participation in this exchange forthwith” – unless  I specifically respond to his vague 4 point challenge (with 3 qualifying points) – makes an early conclusion inevitable.

As this is my last article in the exchange I want to deal with the nature of Paul’s activist organisation – the Fluoride Action Network. This is scientifically relevant because it raises questions about how science should be done and communicated. I will precede that with another look at some of the scientific issues Paul disputes and briefly respond to a number of points he persistently raises.

But first I will respond to Paul’s use of certain “debate tactics” and his criticisms of the comment discussion that has accompanied these articles.

A scientific exchange or a “debate?”

Many readers are familiar with the debating tactics used by the Christian apologist William Lane Craig. He is always promoting himself by challenging others to “debate” him on his own choice of topic. Undoubtedly he is skilled in formal debate procedure and understandably he wants to choose his own “weapons.” But, formal combative debates are more a sport than a way of resolving issues (that is why we never use formal debates in science), more about egos than reality. The objectionable part of Craig’s approach is his use of the debate format as his way of attempting to control discussion. He tries to determine what subjects are covered and demand discussion centre around his own arguments. Intrinsic to his approach is to continuously pass judgment on his discussion partners – declaring they have not dealt with his argument, have failed to counter them, etc. Acting as the de facto debate judge he attempts to center discussion around his own arguments and will inevitably declare his opponents have lost the debate. This judgement is of course faithfully reported by his followers – to hell with the content of the discussion.

Do readers recognise the similarity to Paul’s approach, or should I spell it out? No, I think it is clear.

Right from the beginning I insisted this exchange not be a debate in the gladiatorial sense (even though we have tended to use the term loosely in titles, etc). I rejected Paul’s request the discussion be restricted to his own book insisting we each have our own data and arguments and we should be free to choose and advance our own points. I know Paul did not want this but what could he do?

I think that is the normal mature way to approach scientific exchanges. It should not be about ego but for drawing out the existing evidence and enabling discussion partners to perhaps see things in a light they have not considered. It is not about winners and losers but about attempting to get a clearer picture of reality.

Moderating comments

Paul criticised my moderation of the discussion accompanying this exchange. He is upset that I did not prevent what he sees as personal attacks on him in comments being “part of the visible record on is matter.”

I recognised in undertaking to moderate discussion (a new thing for my blog but something I had been considering) that criticism was inevitable and my moderation would be used as an “excuse” when commenters were not effective. It has certainly been used as an excuse by a number of local anti-fluoridation activists for not participating in the discussion (but this has not stopped a lot of bad mouthing in the background on other forums like Facebook).

My approach to moderation was to hold back comments that were:

  • Clearly spam (such as posting videos without accompanying comment),
  • Extensive copy and paste without personal input (I personally feel insulted when commenters will copy and paste several pages from a book or web site, without any formatting to remove page numbers or add links),
  • Simply abusive without contributing to the discussion or providing information (No, I did not stop comments which were abusive or angry when they did have something of value in their arguments or information).

By repeating Steve Slott’s comment in the body of his article Paul has ensured his readers and supporters will now have Steve’s succinct criticisms and characterisations of Paul in front of them. Paul has extracted a single comment from almost 2000 and ensured it will be part of the public record by placing it in the body of his article. Presumably Steve will by chuffed that his comment was not lost to such readers by being buried in the comments section. Perhaps Paul would have been wiser to leave things as they were.

But perhaps Paul is suing this comment as a diversion – or an excuse to accuse me of some sort of unethical behaviour. Or maybe this just results from his regular email contact with New Zealand anti-fluoride activists who are currently doing the same and discussing their “distaste” for me with them.

Correcting some misrepresentations

Sorry about the brevity and large number of these responses – a bit of responsive “Gish galloping” on my part!

Paul claims I argue “that water fluoridation is the only way to go as far as fighting tooth decay is concerned” yet I have never argued that at all. Several times I have pointed out that other countries use different social policies like fluoridated salt, fluoridated milk, school mouth rinse programmes etc. I would be perfectly happy to see New Zealand switch to fluoridated salt, for example, if fluoridated water proved unacceptable to the majority of the population. In some ways fluoridated salt may work better than water because it would not be under the control of local councils vulnerable to being “picked off” by activist groups. And sometimes I question the technical possibility of reaching the more than 70% coverage through community water fluoridation required to reach the whole population.  Salt fluoridation was discussed quite a lot in the comments discussion.

He claims I have a “distaste for opponents of fluoridation in NZ.” He is wrong (I have friends and family members I love who disagree with me on this question). But yes I do have a distaste for the tactics used by some of the activists. I also object strongly to the arrogant misrepresentation of the science commonly advanced by these activists. I find the fact Paul is in email contact with local activists and discussing their “distaste” for me unpleasant. I can imagine how nasty that discussion gets, but does he think that sort of bad mouthing advances anyone’s case? And has he responded to their bitching by urging them to participate in discussions here (as I have), or did he warn them to keep away?

He accuses me of not acknowledging there could be a problem for some individuals with increased sensitivity to fluoride and that I attack studies and “numerous anecdotal reports that have waved “red flags” on this issue.” Did he miss my comments in my last article that “I am happy to concede there may be a small number of people like this – as for other common chemicals in the environment?” Perhaps he chooses to ignore my conclusion “Maybe the most empathetic solution is that society as a whole compensate this small number of people in some way to aid them with their predicament.”

Paul has several times argued for a “weight of evidence approach” to the literature on fluoride. I will discuss this in greater depth in the section on the Fluoride Action Network. In principle this is exactly the same as my insistence that we should be approaching the literature in an intelligent and critical way. We should be considering all the literature, assessing quality, understanding flaws and strengths, considering the possible role of confounding factors and drawing interim conclusions from this overview. I think examples in this exchange show Paul often does not do that. Instead he often relies on cherry picked papers of poor quality. He even argues the lack of higher quality papers is a point in favour of the poor quality ones, when it may simply indicate other researchers don’t see the effect he wants. And he often claims studies support his conclusions when they don’t.

Paul criticises public funding of an information service in New Zealand set up specifically to facilitate a “weighted evidence approach” towards fluoridation research. Perhaps this shows his hypocrisy in the use of the term. However, Paul is thoroughly confused on this so a little information is required (readers can also refer to my article Anti-fluoridationist astro-turfing and media manipulation).

The NZ Fluoridation Information Service (NZFIS) is not publicly funded as Paul claims. It is an astroturf organisation set up by FANNZ, part of Paul’s International Fluoride Action Network (see Anti-fluoridationist astro-turfing and media manipulation). The astroturfing is so clumsy they use the same contact address as FANNZ! Mary Byrne and Mark Atkin, activists for FANNZ, often act as spokespersons for NZFIS, using the organisation to give an air of credibility to their press releases. This astroturf organisation was also used to provide false credibility to Mark Atkin in an an exchange of opinion article written for the Journal of Primary Healthcare. It is sometimes used to disseminate propaganda for Paul’s FAN organisation using local press releases.

This aura of “credibility” rests on the confusion of the similarity of it’s name to the NZ National Fluoridation Information Service (NFIS). This is publicly funded and part of its role is to monitor the research literature and make summaries available. It is an information and advisory service supporting District Health Boards and Territorial Local Authorities by providing robust and independent scientific and technical information, advice and critical commentary around water fluoridation. It is the organisation that takes a “weighted evidence approach.”

Unfortunately the ploy of using similar names does confuse the news media at times. (The NFIS periodically has to set the media straight.) Apparently it even confuses Paul – and I have seen similar confusion from local anti-fluoridation activists.

Paul is still confused about the graphic I introduced early in this exchange showing data for fluoridated and unfluoridated areas of the Irish Republic. He insists it is a comparison of data for the Irish Republic and Northern Ireland. It is not. How many times must I repeat this?

He again avoids the importance of including social good in ethical considerations of social health policies like fluoridation. This time he does so by pretending that social benefits just don’t exist. And yet he seriously proposes alternatives such as the Scottish ChildSmile programme and the programmes used in other European countries. Fluoride treatments are an integral part of the Childsmile programmes and fluoridated salt and milk is part of the programmes used in many European countries. What this boils down to is his insistence on individual choice as his over-riding concern and his absolute rejection of any concept of balancing this against social benefits. His insistence that fluoride has no beneficial effects and concern for harmful effects is merely an excuse for his concentration on individual choice.

Paul’s emotional (or political) obsession with individual choice often comes though in the most unlikely places. Why should he use the term “forced fluoridation” in a polite scientific exchange? It is equivalent to a politician referring to public education as “forced secular education,” or our public health system as “forced free hospital care.” No one has secular education, free hospital care or fluoridation forced on them. There is always a choice for those prepared to make the effort to satisfy their convictions.

Paul claims I know “full well” he has disowned claims that “Hitler used fluoride to control prisoners.”  No, I didn’t (still haven’t reached  pages 256-258 of his book), but I am very pleased he has repeated his statements here. Let’s disseminate these points far and wide:

Paul Connett rejects the arguments of some of his fellow fluoridation opponents that fluoride has been used “as a method of mind control.” He also rejects speculations that fluoridation is a “sinister plot to ‘dumb down’ the population” or “part of some world wide plan to reduce the size of the global population.”

I hope his fellow anti-fluoridation activists in New Zealand read this and take it on board. I hope they publicise Paul’s comments. I hope spokespersons for the local organisations reprimand any of the supporters who make these claims (far more of them do than Paul seems to think).

And I hope that Paul himself will repeat these assurances during his upcoming speaking tour of New Zealand – and particularly take to task supporters (like local spokesperson Dr Anna Goodwin) who repeat such rubbish. From my perspective he needs to push that message home loudly and often.

So thanks for that Paul – but why did he ignore my similar request?:

“I have yet to see him condemn the atrocious propaganda, lies and personal attacks of propagandists like Alex Jones and Vinny Eastwood. It is not enough to say he doesn’t necessarily support all their positions. The fact that he uses their services, and they use his, makes such weak dissociation disingenuous.”

Is his refusal to condemn  such “atrocious propaganda, lies and personal attacks of propagandists like Alex Jones and Vinny Eastwood” an indication of his support for them?

He claims I wish to “avoid” education on oral health issues. That is just silly and he has no justification for the claim. Proponents of fluoridated water supplies, fluoridated milk, fluoridated salt, fluoride dental treatments, etc., just do not see the world is such a naive black and white way. Fluoridation in any form is not a substitute for good oral hygiene. Health authorities will often operate campaigns of all sorts aimed at fighting tooth decay and education about oral hygiene is very common. We do in New Zealand and Paul has several times referred to such programmes in Scotland.

Paul’s attempts to deny the scientific consensus about the contribution of fluoride in drinking water to increasing concentrations in saliva and tooth surface biofilms has become desperate and farcical. I can only conclude this is because he has been promoting the mantra of “topical application” as a way of hiding the “surface mechanism” message.

He insists I have ignored his claims on margin of safety asking where my comments on this are. Yet, several times he has ignored my request for him to justify the low safety of margin he derives from the paper of Xiang et al (2003). I find it hard to believe he has not seen my requests (although that would be possible if he has not been reading my articles seriously). However, this could just be a cynical ploy as part of his campaign to pretend I am avoiding issues. I mentioned this above in my comment on debating tactics.

Briefly on the pineal gland and calcification (although not as briefly as Paul’s Gish galloping reference to it). It is a favoured subject of many anti-fluoride propagandists and they often give it mystical overtones with reference to a third eye, etc. Calcification is not caused by fluoride – it is caused by calcium, phosphate and old age. Because the bioapatites in calcified tissues are actively undergoing mineralisation and remineralisation they easily incorporate fluoride into their structure and this leads to higher concentration of fluoride in calcified tissues than in bones generally.

A similar situation occurs with calcium rich plaque deposits in cardiac arteries. Li et al (2011) suggested that fluoride incorporated into such deposits could be used to identify their occurrence by measurement of  F-18 using positron emission tomography. They were describing a diagnostic method and yet Declan Waugh and other activists disingenuously use this paper as some sort of “proof” that fluoride increases the risk of heart attacks!

I am surprised Paul has taken the approach of blaming practically every illness or change on fluoride. Arthritis, early onset of menstruation, all the symptoms attributed to “fluoride sensitivity,” osteosarcoma and other cancers, hypothyroidism, and so on. It is a common tactics of the non-scientific, even anti-scientific, rank and file anti-fluoridation activists to blame all the ills of the world on fluoridation – but one expects more from a trained scientist.


Some of the ills fluoride gets blamed for.

Despite the many advantages of modern society we do appear to face an increase in some health problems. Obesity has become far more common, for example. Surely the scientific approach is to attempt to identify the real causes properly. To start by blaming fluoride (or any other chemical) without evidence, is misleading. It is even worse to insist on attributing this as a cause to the exclusion of all else and to demand research only into such a dogmatic hypothesis – as Paul does. This ideologically driven labelling is not only dishonest. It is dangerous as it diverts efforts away from proper objective research and serious investigation of the problems. It inhibits proper identification of causes.

Paul insists on using the authority fallacy – out of context quotations from authoritative figures. An example in his last article was that by David Locker. Perhaps he is not aware he is doing this – it seems to be an instinctive reaction for anti-fluoridation activists. He should appreciate that the world is never as simple as implied by such quotes. I see his resort to such fallacies as a weakness, not a strength.

The Hastings experiment

Paul’s description of the Hastings experiment is biased and reeks of conspiracy theory. He has since included the same information in an internationally distributed newsletter entitled “New Zealand Fluoridation Fraud.” This is being disseminated in New Zealand and, I suspect, Paul will push this story during his upcoming speaking tour here. I always consider allegations of scientific fraud  to be very serious. Usually a researcher’s whole career is at stake as it is one the most serious allegations that can be made.

Typically, Paul’s bias means he relies on a single source for his story. He writes that he “would be anxious to see if Ken can throw a different light on this matter.” While this is not the place to give a full and more balanced history of the Hastings experiment (and I haven’t done the research for this) I will make just a few comments to expose Paul’s bias.

Paul quotes John Colquhoun:

“The school dentists in the area of the experiment were instructed to change their method of diagnosing tooth decay, so that they recorded much less decay after fluoridation began.”

This just shows how simple facts can be distorted to fit a conspiracy theory. My own family remembers this change in dental technique by the school dental service because it was country-wide – not restricted to Hastings as Colquhoun, and Paul, imply. There goes the conspiracy theory and Paul’s claim of a scientific fraud.

Akers (2008) agrees these changes confounded the experiment:

“The changing of NZSDS [NZ School Dental Service] diagnostic criteria for caries and the cessation of the NZSDS nurses’ practice of prophylactic restoration of fissures further confused interpretations. While later antifluoridationists justifiably claimed that the changed diagnostic criteria contributed to the fall in caries (Colquhoun, 1999), their “science or swindle” questioning of methodology and findings (Colquhoun and Mann, 1986; Colquhoun, 1998; Colquhoun and Wilson, 1999) simplified confounding variables and dismissed international evidence supporting community water fluoridation as one factor in declining community caries incidence (de Liefde, 1998).”

So science, probably bad science, but not the “swindle” Paul wants to believe – and wants us to accept. As an aside, I think changes in dental practice like this will have also contributed to the graphs Paul and other anti-fluoride activists love to use to prove improvement of oral health in the absence of fluoridation – yet they never discuss that sort of detail. It is a potential problem with any longitudinal study and Colquhon was criticised for ignoring it in his own presentation of New Zealand data.

Akers also refers to the problem with using Napier as a control city:

“The abandonment of the control city (Napier) because it had a lower initial caries rate than that of Hastings (Ludwig, 1958) implicated soil science as a confounding factor in New Zealand cariology (Ludwig and Healey, 1962; Ludwig, 1963).”

I referred to my memories of this discussion about the role of other trace elements in dental health in a previous article (see Why I support fluoridation).

Yet, how does Paul express this: “after about two years the control city of Napier was dropped for bogus reasons.” So Paul considers the fact it was not suitable as a control to be bogus?

The Hastings experiment (or “project” or “demonstration”) was also confounded by political changes, birth of the anti-fluoridation activity in New Zealand, loss of support from the Hastings City Council, and so on.

That is the problem with conspiracy theories – they paint the world black and white which is very unrealistic. I expected far more professionalism from Paul than this.

The Scottish ChildSmile programme

Paul returns to this through quoting material from Bruce Spittle. What I find a little weird is that his original reference to this programme was as an argument for an alternative to fluoridation. But he seems oblivious that Bruce’s note reveals that use of fluoride varnishes is an integral part of the programme.

In fact the programme includes this target:

“At least 60% of 3 and 4 year old children in each SIMD quintile to receive at least two applications of fluoride varnish per year by March 2014.”

It is an excellent programme but only Paul seems to see it as an alternative to use of fluoride. Here is a quote from the ChildSmile programme:

“The Scottish Dental Clinical Effectiveness Programme (SDCEP) Prevention and Management of Dental Caries in Children guidance outlined that the benefits of fluoride varnishing should be extended to all children. They recommend fluoride varnishing twice a year to all children over two years of age.

Even at very low levels, fluoride in the plaque and saliva is able to alter the balance between demineralisation and remineralisation, favouring the remineralisation process. As the remineralisation happens in the presence of fluoride, the new mineral crystals are stronger and less susceptible to acid attack.

When fluoride is present in the saliva, the fluoride ions become concentrated in the plaque. When sugars then enter the plaque, the presence of fluoride reduces the conversion of dietary sugars into acid by plaque bacteria with less acid produced.

How fluoride varnish works:

  • it slows down the development of decay by stopping demineralisation
  • it makes the enamel more resistant to acid attack (from plaque bacteria), and speeds up remineralisation (remineralising the tooth with fluoride ions, making the tooth surface stronger and less soluble)
  • it can stop bacterial metabolism (at high concentrations) to produce less acid.

Fluoride varnish leads to heavy remineralisation of the enamel surface, and subsequent acid attacks will allow fluoride ions to penetrate more deeply into the tooth structure. Varnishes like Duraphat® are useful because they stay on the tooth surface for some hours, allowing slow release of the fluoride ion.”

Improving oral health and effects of stopping fluoridation

Despite our discussion of the errors in drawing the conclusions he does from declining tooth decay in European countries he continues to naively present that as “proof” fluoride plays no role in oral health. And he is still completely confused about the Irish data I presented – this was for one country, Ireland. I was not comparing Northern Ireland and Ireland in any way. His claims that oral health shows no decline when fluoridation is stopped involves a similar misrepresentation of the evidence.

I am glad he acknowledges the protective role of other fluoride treatments after fluoridation was stopped in La Salud, Cuba, and the former DDR. But seriously, did he not know that already? Had he not checked out the studies which activists rely in to make these claims? And will he now stop using those examples in future presentations and discussions? I suspect not.

This shows all the earmarks of cherry picking studies to confirm his bias and basing arguments on studies he has not bothered checking. He attempts to deflect criticism by saying “It is not clear if Ken believes that alternative methods were applied to explain the results in Finland and British Columbia.” Well, perhaps I should spell it out – I don’t have a “belief” about those studies because I have not checked them out. But I suspect they do not support Paul’s arguments against fluoridation any more than the Cuban and German studies do. (After all I am sure Paul would be describing the details by know if they did). He has already lost that argument and he is desperately clutching at his remaining straws while the rest of us have moved in to the next issue wishing to spend our valuable time on more important things.

Once again I can illustrate some of the problems with his cherry picking and simple interpretations by comparing the changes in oral health of two Scottish communities described in a study by Attwood and Blinkhorn (1991), “Dental health in schoolchildren 5 years after water fluoridation ceased in South-west Scotland.”

This compared caries prevalence in two towns in both 1980 and 1988. One town, Annan, had never had fluoridated water while the other, Stranraer, had it until 1983. The graphics show the results for 5 year old and 10 year old children.


Decayed missing and filled deciduous teeth for 5 year olds. Stranraer fluoridated until 1983. Annan not fluoridated.


Decayed missing and filled teeth for 10 year olds. Stranraer fluoridated until 1983. Annan not fluoridated.

Paul might want to seize on the Annan results to argue that fluoridation has no effect on oral health as they show the same pattern as the European data he loves to present. But in this case we see that stopping fluoridation did have a significant negative effect on caries prevalence for Stranraer – even though oral health of these children in the two towns was similar in 1988.

I fully accept this is just one study, and by itself is not conclusive (I don’t claim it is). Nor have confounding factors been considered. Paul can claim I have “cherry picked” it. All perfectly valid criticisms – but that only describes the process used by Paul and his fellow activists. They have chosen papers they think supports their case. That is not good science. We should be basing our conclusions on on a proper critical and intelligent review of all the studies – not selecting ones which suit us.

Even with the study of Attwood and Blinkton described above activists from either side of the fluoridation debate can select or cherry pick “evidence” to fit their predetermined case. To argue either that it “proves” fluoride is not effective for oral health as shown in Annan where tooth decay declined despite there being no fluoridation. Or to argue that it “proves” fluoride is effective because oral health declined after fluoridation in Stranraer was stopped.

Nature of Fluoride Action Network

Ii is important this exchange not finish without considering the nature and role of Paul’s activist organisation, the Fluoride Action Network (FAN). I commented in previous articles about the problems of scientists becoming involved in activism. FAN illustrates those problems of cherry picking, confirmation bias and group thinking. Here I will comment on some of the specific ways these are manifested in FAN and it’s international role in the anti-fluoridation movement.

Martin (1991) and Newbrun (1996, 1999) described the social base of anti-fluoride activism as a weird mixture of fundamental greenies, misguided environmentalists, food faddists, anti-science “naturalists,” chiropractors and right-wing extremists. I guess readers could add more to this list but anyone who has watched the videos of the submissions made by anti-fluoridation activists to the Hamilton City Council hearings this year will recognise all these elements. They are all ideologically driven, illustrate characteristics of cherry picking, confirmation bias and group thinking, and make extensive use of the services FAN provides.

These social groups, and their associated businesses, also provide an organisational and financial backing to FAN and it’s regional organisations like the Fluoride Action Network of NZ (FANNZ). One current example is the NZ Health Trust which attempted to get a judicial review of South Taranaki’s decisions on fluoridation in the High Court.

FAN works hard to select scientific literature which can be interpreted, or reinterpreted, to support the anti-fluoridation case. They have accumulated a large database of such literature – a useful resource for the naive internet commenter wishing to “prove” fluoridation is evil. This database, and its extensive internet use by activists, has produced high Google search rankings for articles promoting an anti-fluoride case – frustrating for the honest Google user attempting to find more objective material.

The organisation certainly searches far and wide for any scientific report or paper which can be used to further their cause. Apparently the normally accessible scientific literature has not been fruitful enough for this purpose so they are making more use of obscure foreign sources. They have put a lot of effort into translation of Chinese publications and recently put out a request for people to translate foreign material in other languages.

Clearly FAN is searching for anything that can be used as “evidence” for negative effects of fluoride in human and animal health. This is not a critical or intelligent approach to the literature. I am all for the possibility of finding interesting ideas in foreign untranslated and obscure papers – I have done so myself. But the FAN motives are all wrong. They are uncritical, unintelligent and selective in their search. The quality of the research they use is their last concern – which is hypocritical considering the frequent demands for proponents of fluoridation to produce replicated double-blind studies.

The FAN database gets a lot of unintelligent use by fluoride activists throughout the world. Naive quoting and citing is very common in social media like Twitter and Facebook. Commenters in blogs will often simply post a quote or even just a link – drive by trolls. People who commonly read and use the scientific literature properly shudder to see such unintelligent use as it downgrades the idea of scientific knowledge.

FAN also makes videos available for similar use.

In effect FAN heads an international network. There are “action networks” and “fluoride free” organisations in many countries and regions where fluoridation is an issue. In New Zealand there is FANNZ, as well as regional Fluoride Free structures and Facebook pages. Mary Byrne, National coordinator of FANNZ is also a Advisory Board member on Paul Connett’s FAN organisation.

These international links are apparent in the way that media is manipulated by planting propaganda material. FAN will issue press releases which get faithfully transmitted by the alternative media connected with conspiracy theorists, natural and alternative medicine and practitioners, food faddists, some environmental groups, etc. These press releases also get planted locally by groups like FANNZ, sometimes using its astroturf group, the NZFIS. They also get picked up and reproduced by bloggers. Links and simple, very often misleading, one liners get transmitted ad nauseam by Twitter and Facebook.

Sometimes the normal mass media will reprint a press release, or pick up an article from elsewhere giving it a prominence it doesn’t deserve. And of course, these are immediately promoted on Facebook and Twitter as if they were independently sourced stories.

Example of Israel and it’s decision to regulate on the mandatory stays of fluoridation.

Whether intentionally, or just because of human foibles, part of international promotion is the use of personality cult. We can see this in New Zealand with Paul’s upcoming speaking tour. Locally he is being promoted and advertised  as the “World Fluoridation Expert” – despite the fact that he has no research papers to his name on the issue. In a previous article I referred to his claimed 18 years research into fluoride and his self promotion as an expert:

“with such a reputation it is reasonable to expect a body of publications in reputable peer-reviewed scientific journals. My simple searching does not show any, although he does list 2 which I could not find on-line in a recent CV. Could Paul give us a relevant publication list? And links to the papers.”

Significantly, this is another of my questions Paul has chosen to ignore.

Local Facebook advertisement for Paul’s NZ tour.

Paul also has remained silent on my critique of the Fluoride journal and his relationship to it. His organisation FAN is currently campaigning to win respectability for that journal in the wider scientific community. I can understand FAN’s motives for this – but the tactics? Promotion of a journal by an activist organisation which often attacks science and scientists would normally be considered the kiss of death.

Concluding comments.

This is the last article in my exchange with Paul Connett. Although, if he insists, I will not deny him the right of reply.

I have enjoyed the exchange. It has been useful for me to get my ideas into some sort of order and to get a measure of the arguments used by opponents of fluoridation. In that respect I am conscious that Paul does not adhere to some of the common arguments used. I am glad he dissociates himself from some of the extreme right-wing propaganda in the anti-fluoridation movement claiming an Agenda 21 conspiracy to control population and keep us dumb. Nor does he promote the silly arguments claiming fluoridation was used for this purpose by Nazis in the concentration camps. The negative side is that we did not get to see those arguments presented properly and I did not get to look at them more critically.

There have been a large number of comments on these articles and I believe they are of higher quality than we commonly see in discussions of fluoride. Many commenters have presented useful arguments and information with many useful citations. I have found these valuable and urge readers to go back and browse comments for them.

The links to all the articles in the exchange are listed by date on the Fluoride Debate page. In the new Year I will put the articles together in a PDF document (and maybe an eBook format) so readers can download and consult at their leisure. Maybe we could even use Paul Connett’s speaking tour of New Zealand early in the year to encourage people to read the exchange.

Finally thanks to Paul Connett for agreeing to this exchange (it was actually his idea to try it as an on-line exercise) and to all the people who participated in the comments discussion.

Fluoride debate: Arguments Against Fluoridation Thread. Part 8. Paul

This is Paul Connett’s response to Ken Perrott’s last article Fluoride debate: Response to Paul’s 5th article

For Paul Connett’s original article see – Fluoride debate Part 1: Connett.

Ken’s response to my last posting once again is incomplete and evasive. Let me review what has happened here.

Ken was asked to present the case FOR fluoridation. After four attempts Ken has produced very little science to support such a case.  In part 6 of this thread I laid out what I felt would be the necessary components for such a scientific case and asked some very specific questions in the hope that Ken would present that case.  Ken’s response has been disappointing

Ken’s response in part 7 of this thread

Apart from further discussion on the theoretical mechanism of fluoride’s topical mechanism of action, a few citations on benefits, more criticisms of the opponents of fluoridation and more discussion on the ethical arguments Ken failed to present many primary scientific studies to support the case for fluoridation. Instead, he either ignored the questions I posed, was evasive or sought to obfuscate the key issues I presented. This meandering response may satisfy Ken’s urge to demonstrate his general distaste for opponents of fluoridation in NZ (based on the emails I have received this distaste cuts both ways) but it does not advance his scientific case for fluoridation one iota.

Instead of making a serious or even good faith effort to address the scientific questions I posed he attempted to dismiss my whole effort by claiming that I was unfairly throwing the kitchen sink at him (my words). His own words were new to me. He described my series of specific questions as follows,

 “It’s a real Gish gallop – suddenly demanding answers about arthritis, kidney function, thyroid function, osteosarcoma, individual sensitivity to fluoride, menstruation, effect on babies, monitoring bone concentrations and finally, all or any health concerns in New Zealand. Without any background to any of the issues.  (Wikipedia describes Gish gallopers as using ‘a rapid-fire approach during a debate, presenting arguments and changing topics quickly’). “

As far as Ken’s claim that I have failed to present the background to my questions he is wrong on two counts. First, I have raised several of these issues before in one or both of our threads – thus there is nothing sudden about many of these questions. Second, plenty of background was laid down on all of the issues in our book The Case Against Fluoride, a pdf copy of which was sent to Ken over a month ago.

If Ken was more familiar with the literature he would have known that the response to each question I posed was not difficult at all.

One sentence on most of these questions would have sufficed, for the simple reason that incredibly NO (or very few) studies on these topics have been undertaken in NZ or other fluoridated countries like Australia, Canada, Ireland, Israel, the US or the UK. More specifically:

1) There have been NO attempts to investigate arthritis rates in fluoridated communities in NZ or other fluoridated countries, even though it is known that the first symptoms of fluoride poisoning of the bone are identical to arthritic symptoms. I have given citations to some of these studies.

2) There have been NO attempts to investigate a possible relationship between fluoridation and an earlier onset of menstruation in young girls or puberty in boys in fluoridated communities in NZ or other fluoridated countries, even though there is some evidence that this maybe occurring (Schlesinger et al., 1956) as well as Luke’s work on the pineal gland (Luke, 1997, 2001).

3) Neither NZ nor any other fluoridating country has attempted to investigate the issue that some individuals report increased sensitivity to fluoride even though independent observers (e.g. Taves, discussed in chapter 13 of our book) and one governmental organization (Australia’s NHMRC, 1991) have recommended that this sensible measure be undertaken. Ken does not acknowledge this and misses the point by attacking the studies and numerous anecdotal reports that have waved “red flags” on this issue.

4) There have been NO systematic or comprehensive efforts by government health agencies to monitor the fluoride levels in the urine, blood or bones of any fluoridated community in NZ or any other fluoridated country.  Australia’s NHMRC in 1991 recommended bone levels be collected as a basis for epidemiological studies on fluoride’s impact on the bone but no attempt has been made there in the 22 years that have elapsed since this recommendation was made; nor in NZ.

5) There has been NO published study refuting Bassin’s finding of an age-related window of vulnerability (ages 6 through 8) for young boys being exposed to fluoridated water and succumbing to osteosarcoma. The promised study (Kim et al, 2011) miserably failed to refute this finding despite the promises made in 2006 that it would do so.

6) There has been little or no attempt to see if the current epidemic of hypothyroidism in NZ and other fluoridated countries has anything to do with exposure to fluoride even though doctors in Argentina, France and Germany used fluoride treatment to lower thyroid activity in hyperthyroid patients from the 1930s to the 1950s (See Galleti and Joyet, 1958).

7) There have been practically NO studies investigating possible health concerns in NZ possibly associated with fluoridation. Nor have there been attempts to reproduce studies that have found harm in countries with high natural fluoride levels. I was not aware of any studies in NZ other than a small IQ study from the 1980s but I thought it wise to find out if Ken knew of any. But he didn’t respond. I also asked him if he felt the absence of study was the same as the absence of harm but again he didn’t respond.

8) There have been a number of studies on teeth in NZ and other fluoridated communities as if this was the only tissue of concern in the baby’s developing body or of concern for adults with lifelong exposure. Ken has still yet to discuss the wisdom – or otherwise – of exposing a bottle-fed baby to about 200 times the level of fluoride that nature intended (0.7 ppm in fluoridated water versus 0.004 ppm in mothers’ milk).

9) In short. While the NZ government has poured over $1 million into the NZ Fluoridation Information Service, which is little more than a PR operation for fluoridation, they have taken little or no steps to fund any primary studies to see if this practice is harming anyone in NZ.

More Broad-brush dismissals

On the issue of fluoridation’s effectiveness Ken attempts to use the same broad-brush dismissal of the citations I offered in support of my case that evidence for swallowing fluoride reduces tooth decay was very weak. Ken responded:

“So, I am not impressed by Connett’s paragraph of about 30 unexplained citations – nor by a long reference list at the end of his article.”

I am baffled as to why he should describe these citations as “unexplained” when I made it clear that the citations were all discussed in three chapters of our book (chapters 6-8).  Ken had already explained that he had read up to chapter 9 in our book so his claim that the citations are unexplained is rather sloppy. As far as the number of citations is concerned it would be more understandable if Ken was complaining about my giving too few citations, not too many!

I ask the reader to consider for a moment, which is more convincing – my extensive list of references to the literature which suggest the ineffectiveness of fluoridation or the very sparse list of references provided by Ken which he claims support the effectiveness of fluoridation. However, at least he gave some references here; he gave none on the health concerns I raised.

Instead of responding scientifically – or at least conceding that the science has not been undertaken – Ken chose to either ignore or obfuscate most of the scientific issues I raised in the following ways:

1) His response is very familiar. He chose to attack the messenger and ignore the message. From Ken’s perspective there is nothing wrong with the practice and promotion of fluoridation – it is Paul Connett and other opponents of fluoridation who are the problem!

2) Really substantial issues I have raised are being ignored, in some cases for the second and even third time of asking. For example where are his comments on the

a) difference between dose and concentration;

b) the need for a margin of safety analysis when extrapolating from the doses that cause harm in animal and human studies and

c) the need for a weight of evidence approach to the scientific literature on this subject.

 3) Where Ken does address an issue his response has often been evasive and clouded with obfuscation. For example see his response to my reasonable scientific request for a list of studies that negate or balance out (i.e. weight of evidence analysis) the long list of studies that indicate that fluoride can damage animal brain and interfere with human behavior and intellectual development. His response was to classify such a request as “the IQ gambit” and to bring up the distraction of “Hitler using fluoride to control prisoners” when he knows full well that I have disowned such claims in public and in writing. See for example, these quotes from our book:

“It is true that a few people who oppose fluoridation do so based on claims that Nazi Germany and other totalitarian regimes used it as a method of mind control. There is little evidence that would satisfy a historian to support such claims. The vast majority of fluoridation opponents repudiate such views and base their opposition on science and ethics.” (pp. 256-7)


“Two speculations we reject outright are that fluoridation is (1) some sinister plot to“dumb down” the population or (2) part of some worldwide plan to reduce the size of the global population.” (p.258)

4) Thus, Ken has still to present a substantial case FOR fluoridation based upon the citation of primary studies.

5) Unfortunately, he is leaving it to others to present some of his case in the comments section. I made it clear to Ken when we discussing the format of this debate that I was not interested in these kind of blog comments which become very personal and sometimes insulting. I thought we had agreed that this was going to be a scientific exchange between the two of us. I am not prepared to sift through the insulting chaff in the comments section to get to the scientific wheat.

Someone has forwarded to me a recent personal attack on me by Steve Slott, DDS:

Steve Slott | December 19, 2013 at 1:40 pm |

You got it Stuart. Sarah Palin epitomizes the antifluoridationist. Being totally oblivious to her own ignorance she just blusters along, totally bewildered as to why she gets no respect from the mainstream.

Forgive me for straying off topic, Ken, but the most frustrating thing about antifluoridationists is their ignorance, and their total oblivion to it. Somebody like Connett comes along with just enough education and charisma to come across as being an “authority” on the issue, yet totally lacking understanding of basic facts, far overestimating of his own knowledge, and convinces the blind followers who crave any and all anti-authoritarian causes, that the establishment is corrupt, ignorant, and lacks the “knowledge” that only he possesses through his “study” of new “emerging science “. Being totally unaware that what is “new science” to him is nothing more than basic knowledge of which the true experts and authorities have long since been aware and have fully addressed, he blusters forward confident that he has the “truth” on his side. The worldwide body of respected healthcare is either “corrupt “, conspiracy laden, or ignorant of the “facts” that he is trying his utmost to bring to their attention. Dentists are running the fluoridation show, yet are all dumber than doorknobs and totally lacking in any knowledge of the human body outside of the portions of the teeth that are visible above the gum line, and decision makers are all unwittingly manipulated by big money interests. The people to whom he plays buy into his spiel, lock, stock, and barrel, thus becoming in their own minds far more knowledgeable about the issue than the dumb dentists, corrupt mainstream healthcare, and unwitting politicians who are stripping away personal freedoms and poisoning everyone in the process. Portland and Wichita are poster-children for the chaotic circus side-show that he creates by convincing a very active, very vocal, very ignorant few, of the “validity” of his own ignorance.

Steven D. Slott, DDS

Ken you are the moderator of the comments posted on your website, can you explain to me how this comment contributes to the science of this debate? Can you explain to me why you allow this kind of personal attack on your opponent – completely unrelated to any scientific argument that I have raised – to be part of the visible record on this matter? Just what purpose does it serve other than to muddy the waters and poison the minds of any independent observers?  Surely such a posting has no place in a debate that is supposed to be about the science of this controversial issue.

Now I will address some of the issues on which Ken offered a response.

1) On Randomized control studies (RCT).

 I complained that after 68 years no government promoting fluoridation has undertaken an RCT to demonstrate effectiveness. This is the gold standard in epidemiology. In response , Ken suggests that I should have done an RCT of my own!

As far as safety is concerned I agree that you cannot prove a negative, however such an argument neither explains nor excuses the lack of responsible attention to health concerns by fluoridating countries.  The absence of study on many very important health concerns is inexcusable and cannot be explained away with rhetoric.

2. The ethical argument.

 Ken claims that opponents of fluoridation merely focus on the violation of informed consent and ignore the social benefits of the program. However, that line of argument assumes that:

 a) such a benefit actually exists (and Ken hasn’t presented much of a case for that yet);

b) that very little – if any -risk is involved (Ken hasn’t presented much primary evidence to support that);

c) that the benefits greatly exceed the risks (not possible unless Ken has produced a strong case for both a) and b) which he has not;

d) that there are no practical and cost effective alternative social strategies which avoid the violation of the individual’s right to informed consent. In this respect it is very disappointing that Ken has yet to comment on the successful program being used in Scotland to fight tooth decay in children from low-income families there. Nor has he reviewed any of the other programs being used in the vast majority of European countries that don’t force people to drink fluoridated tap water.

 I would also hope that at some point Ken would address the Precautionary Principle as it applies to the ethics of this issue (see chapter 21, in The Case Against Fluoride…)

3) Does tooth decay go up when fluoridation is halted?

 In two of the four studies I cited (from Cuba, former East Germany, Finland and British Columbia) where tooth decay did not go up when fluoridation was stopped, Ken says that other measures were taken in two of those communities (Cuba and former East Germany). That’s a good point. However, it undermines his argument that water fluoridation is the only way to go as far as fighting tooth decay is concerned. If these communities have found alternative methods why aren’t fluoridating governments studying these alternative methods? Again I refer to the successful and cost-effective program with children in low-income families in Scotland.

 It is not clear if Ken believes that alternative methods were applied to explain the results in Finland and British Columbia.

In personal correspondence I have had with Rudolf Ziegelbecker, Jr., from Austria, who has studied this matter (and his father before him) for many years, he maintains that there has been no increases in tooth decay in any of the European countries that have stopped fluoridation.  Is Ken aware of any evidence to the contrary?

 4. Does fluoridated water deliver a significant topical benefit over and above that delivered by fluoridated toothpaste?

 I notice that Ken twice combines discussion of fluoride’s topical exposure via water and via food. He states:

 “So fluoride concentrations in saliva after drinking water or eating food containing fluoride can be quite variable.”

“Fluoride concentrations in saliva and plaque do reach a maximum after drinking water and eating food containing fluoride…” 

This is interesting because it goes back to my original skepticism about drinking fluoridated water doing much of anything in the oral cavity before it goes down the gullet – that is unless one swishes. On the other hand I can understand that any fluoride present in food is going to be made readily available to both the tooth surfaces and the saliva during the chewing of food and therefore may participate in the theoretical mechanisms that Ken discusses.

If, in fact, this mode of delivery (i.e. via food) is the relevant one then Ken would do better either a) to recommend making fluoridated salt available to those who want it in NZ or b) recommend that parents tell their children to swish the fluoridated water in their mouths before they swallow it. But there we are back to education again, and that is something that Ken wishes to avoid. We are also back to the potential harm from swallowing fluoride.

Beyond theoretical mechanisms

Whatever the theoretical mechanism for fluoride’s action (and I will leave it to the specialists in this field to fight that out), as a promoter of fluoridation, Ken still has to demonstrate that the weight of evidence from epidemiological studies indicates that there is a significant benefit from drinking fluoridated water over and above the use of fluoridated toothpaste. I don’t think he has done that.

He has also yet to explain why it is in the largest surveys there appears to be little difference in tooth decay in the permanent teeth between fluoridated and non-fluoridated communities, states and countries (see chapter 6 in The Case Against Fluoride…), with the one possible exception of the comparison between the Republic of Ireland and Northern Ireland, that Ken has cited.

In short, in the majority of the large surveys the relationship between tooth decay and the presence or absence of fluoride in the drinking water does not appear to rise above background noise. However, the relationship between fluoride levels and dental fluorosis certainly does rise above background noise (see chapter 7 in The Case Against Fluoride…) as does the inverse relationship between tooth decay and income levels (see chapter 6 in The Case Against Fluoride…).

Nor has Ken addressed the fact that in the only study that has looked at tooth decay as a function of how much fluoride children were ingesting (from all sources) there was no significant relationship between the amount of fluoride ingested on a daily basis and the level of tooth decay (Warren et al, 2009).

Although the late Dr. David Locker was not opposed to water fluoridation, he did have the integrity to admit in the review of dental studies worldwide, which he performed for the Ontario government in 1999, that:

 “The magnitude of [fluoridation’s] effect is not large in absolute terms, is often not statistically significant, and may not be of clinical significance.”

My final challenge to Ken.

 Ken I have patiently tried to debate the scientific issues with you but apart from your interest in bioapatites and the theoretical mechanism of fluoride’s actions (both interesting subjects but insufficient to demonstrate the wisdom of forced fluoridation) I believe that you have offered little in the way of science to support the case for fluoridation. Meanwhile, as moderator you are allowing insulting and personal attacks on me by people like Steve Slott to be posted as part of this exchange. I am happy to engage in a rational scientific exchange on this issue but not happy for it to be an excuse for an unscientific attack on my integrity.

I would like to extend you one more shot at demonstrating that there is convincing primary scientific evidence, which shows:

 1) That the weight of evidence of the primary studies indicates that drinking fluoridated water provides a large and significant benefit to the permanent teeth.

 2) That the weight of evidence of the primary studies indicates that there is an adequate margin of safety to protect everyone drinking fluoridated water and getting fluoride from other sources from damage to the developing brain documented in areas of moderate to high natural levels of fluoride. Note: that margin of safety should protect for the bottle-fed infant.

 3) My preference would be for you to do the same with other health concerns that I have raised including those where we need to protect someone consuming uncontrolled quantities of fluoridated water over a whole lifetime – but if it simplifies matters for you, then for now I will settle for you just tackling the impacts on the brain (i.e. 2 above).

 4) That the benefits you demonstrate in 1) outweigh the risks I have presented in my book and in these threads.

And that the case you present in 1-4 is so strong that it justifies:

 a) overriding the individual’s right to informed consent to human treatment.

b) overriding the Precautionary Principle

c) ignoring the fact that there are alternative ways of fighting tooth decay which are universally available – and the successful programs that are reducing tooth decay in children from low-income families in countries like Scotland and most of the rest of Europe without forcing this practice on people who don’t want it.

As far as the Scottish program is concerned we can add a few more bones to the BBC report I included earlier. This is how my colleague Dr. Bruce Spittle summarized the situation in Scotland:

Instead of water fluoridation, the newly devolved Scottish Government opted, in its 2005 dental action plan (their Childsmile program), to pursue:

a) school-based toothbrushing schemes;

b) the offering of healthy snacks and drinks to children;

c) oral health advice to children and families on healthy weaning, diet, teething and toothbrushing;

d) annual dental check-ups and treatment if required, and

e) fluoride varnish applications  (The Scottish Government, 2005; Macpherson LMD et al., 2010; Turner S et al., 2010; Chestnutt, 2013; Healthier Scotland, Scottish Government, 2013).

Encouraging results have been reported from this national dental programme with the proportion of children in Primary 1 (aged 4–6 years) without obvious dental decay rising from 42.3% in 1996 to 67% in 2012 (Information Services Division  Scotland, 2012).

Similarly, the proportion of children in Primary 7 (aged 10–12 years) without obvious dental decay rose from 52.9% in 2005 to 69.4% in 2011 and 72.8% in 2013 (Information Services Division Scotland, 2013).

The introduction and uptake of nursery school toothbrushing is likely to have contributed to a large extent to the improved oral health in five-year-old Scottish children (Macpherson, 2013).

I know these are tough challenges but they are the kind of challenges that should have been tackled years ago by government agencies promoting the unusual (and I say unacceptable) practice of using the public water supply to deliver human treatment. But they weren’t. But for those who continue to support this practice like you the tasks above have to be addressed.

If you are not prepared to attempt this challenge in good faith then I will end my participation in this exchange forthwith.

Paul Connett,

Dec 22, 2013


Bassin EB  et al. (2006). “Age-specific Fluoride Exposure in Drinking Water and Osteosarcoma (United States),” Cancer Causes and Control 17, no. 4: 421–28.

Connett, P., Beck, J and Micklem HS. The Case Against Fluoride. Chelsea Green, White River Junction, Vermont, 2010.

Galletti P. and G. Joyet (1958). “Effect of Fluorine on Thyroidal Iodine Metabolism in Hyperthyroidism,” Journal of Clinical Endocrinology 18, no. 10: 1102–10.

 Healthier Scotland, Scottish Government, NHS Scotland (2013). Childsmile: home, parents and professionals. Available from: http://www.child-smile.org.uk/sitemap/index.aspx

Information Services Division Scotland, NHS National Services Scotland (2012). National Dental Inspection Programme 2012 Report. Available from: https://isdscotland.scot.nhs.uk/Health-Topics/Dental Care/Publications/2012-11-27/2012-11-27-DentalNDIP-Summary.pdf?27395266295

Information Services Division Scotland, NHS National Services Scotland (2013). National Dental Inspection Programme 2013 Report. Available from: https://isdscotland.scot.nhs.uk/Health-Topics/Dental-Care/Publications/2013-10-29/2013-10-29-NDIP-Summary.pdf?27395266295

Jones CM, Woods K, Taylor GO (1997a). Social deprivation and tooth decay in Scottish schoolchildren. Health Bull (Edinb) 55:11-15.

Kim FM et al. (2011). “An assessment of bone fluoride and osteosarcoma.” J. Dent. Res 90(10): 1171-6.

Locker, D (1999). Benefits and Risks of Water Fluoridation: An Update of the 1996 Federal-Provincial Sub-committee Report, prepared under contract for Public Health Branch, Ontario Ministry of Health First Nations and Inuit Health Branch, Health Canada (Ottawa: Ontario Ministry of Health and Long Term Care, 1999.

Luke, J, 1997, “The Effect of Fluoride on the Physiology of the Pineal Gland,” PhD thesis, University of Surrey, Guildford, UK, 1997. Excerpts at http://fluoridealert.org/studies/luke-1997/ and a complete copy of Dr. Luke’s dissertation can be downloaded at http://www.fluoridealert.org/wp-content/uploads/luke-1997.pdf  (with the author’s permission).

Luke, J, 2001.  “Fluoride Deposition in the Aged Human Pineal Gland,” Caries Research 35, no. 2 (2001): 125–28.

Macpherson LMD, Ball GE, Brewster L, Duane B, Hodges C-L, Wright W et al. (2010). Childsmile: the national child oral health improvement programme in Scotland. Part 1: establishment and development. Br Dent J 209:73-78.

Macpherson LM, Anopa Y, Conway DI, McMahon AD (2013). National supervised toothbrushing program and dental decay in Scotland. J Dent Res 92:109-113.

McMahon AD, Blair Y, McCall DR and Macpherson LMD (2010). The dental health of three-year-old children in Greater Glasgow, Scotland. Br Dent J 209:E5. doi: 10.1038/sj.bdj.2010.723.

NHMRC (1991). National Health and Medical Research Council, The Effectiveness of Water Fluoridation (Canberra: Australian Government Publishing Service, 1991), 109.

NRC (2006). Fluoride in Drinking Water: A Scientific Review of EPA’s Standards (2006) http://www.nap.edu/catalog.php?record_id=11571

Schlesinger ER, et al. (1956) “Newburgh-Kingston Caries-Fluorine Study XIII. Pediatric Findings After Ten Years,” Journal of the American Dental Association 52, no. 3: 296–306.

Warren, JJ et al. (2009) “Considerations on Optimal Fluoride Intake Using Dental Fluorosis and Dental Caries Outcomes—A Longitudinal Study,” Journal of Public Health Dentistry 69, no. 2: 111–15.

Anyone wanting to follow the debate and/or check back over previous articles in the debate can find the list of articles at Fluoride Debate.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page

Fluoride debate: Arguments Against Fluoridation Thread. Part 5. Paul

This is Paul Connett’s response to Ken Perrott’s last article  The fluoride debate: Response to Paul’s 6th article.

For Paul Connett’s original article see – Fluoride debate Part 1: Connett.

Here is my response to Ken’s last response to this thread (part 4).

Propaganda from Queensland Health

 1) The pictures below appeared on page 2 of a 4-page leaflet from Queensland Health used to promote mandatory fluoridation in 2007. It compares pictures of the teeth of a child who has had its teeth “exposed to fluoridated water” (beautiful) with the teeth of a child “without exposure to fluoridated water” (atrocious).

QLD Health brochure

In response to this figure Ken writes:

  “It seems to have been taken from a document prepared under the Queensland Health logo. I cannot find a source and no-one seems to be able to give a citation. It is not on the Queensland Health web site.” (my emphasis)

Why does Ken say “seems”? I forwarded a copy of the whole leaflet to Ken. Does he doubt the authenticity of that leaflet?  I have no doubt at all about its authenticity.  Mind you, I am not surprised – now that citizens in Queensland have pointed out this outrageous piece of state-funded propaganda – that Queensland Health is embarrassed and should want to hide all traces of it.

2) I think it was disingenuous of Ken to try to nullify this outrageous propaganda by providing a link to a leaflet produced by an anti-fluoridation group. The point I was making (in part 3 of this thread – originally part 1A) is that it is one thing for citizens – either promoters or opponents – to use tactics like this (I certainly do not condone or endorse any side using such tactics) but it is quite another when bureaucrats working for the state and paid by taxpayers to protect their health stoop to such tactics. It is unacceptable. Nor should it be necessary if this practice was as “safe and effective” as the promoters claim. Surely the role of civil servants is to provide objective information on a controversial issue not side with one side and then provide outrageous spin in support of that side.

3) Ken did not respond to my other concerns about the propaganda used by Queensland Health. This is less dramatic perhaps but equally deceptive. This was their claim in newspaper ads (see picture below) that there was a 65% difference in tooth decay between fluoridated Townsville and non-fluoridated Brisbane (see picture below).

Newspaper ad

To get this 65% reduction Queensland Health had selected the number for the relative difference for just one age – 7 year olds.  In Table 4 – in the paper by Slade et al.,  (see below) readers will see that this 65% relative reduction amounted to an absolute saving of a measly 0.17 of one tooth surface. Their arithmetic is accurate but a 65% reduction sounds a whole lot more impressive than a saving of 0.17 of one tooth surface. This is a deliberate attempt to mislead the public. In other words, it’s PR spin. I would be interested to hear how Ken would describe it.


Returning to the photographs in the Queensland Health brochure, does the difference in these two sets of teeth look like a difference of 0.17 of one decayed, missing and filled permanent tooth surfaces (DMFS)?

I wish I could say that this blatant propaganda on behalf of personnel at Queensland Health is an aberration among civil servants in the health agencies of the countries practicing fluoridation. Sadly, from my personal experience, it is not.

I have seen first hand outright propaganda from people at the highest levels of civil service in the health agencies of several fluoridating countries as well as their minions in their bureaucratic chain of command.

The propaganda of these civil servants is shameless but sadly gobbled up by the media and too many local decision makers in their respective countries. One would have hoped that scientists like Ken Perrott with their sensitive antenna to scientific misrepresentation would have helped expose this sad state of affairs. Instead of doing this they fire their rhetorical guns at the citizens who are doing their very best – with limited resources – to bring this state-financed propaganda to the attention of the media, the public and their political representatives – but it is an uphill job.

4) In NZ the manipulation of the science on this practice goes back a long way – in fact to the very first trial of fluoridation in Hastings (with Napier as the control city). This trial was carried out from 1954 to 1964 and has been shown by the late Dr. John Colquhoun and his PhD thesis advisor Dr. Robert Mann and others to have been a scientific fraud (Colquhoun and Mann, 1986; Colquhoun, 1987 and Colquhoun and Wilson, 1996).

5) Ken might wish to comment on the following candid letter sent out by the Director of the Division of Dental Health, Dr. G. H. Leslie, in 1962 – some eight years into this 10-year trial.


I have typed out this letter to make it easier for people to read, as some of the letters are not clear:

 Mr. Swann,

 I have delayed acknowledging receipt of Dr. Roche’s letter to you and replying to your minute in the hope that I would by now be able to give a positive reply to your enquiry. I still cannot.

 No one is more conscious than I am of the need for proof of the value of fluoridation in terms of reduced treatment. It is something which has been concerning me for a long time. It is only a matter of time before I will be asked questions and I must have an answer with meaning to a layman or I am going to be embarrassed and so is everyone else connected with fluoridation. But it is not easy to get. On the contrary it is proving extremely difficult. Mr. Espia is conferring with Mr. Bock and Mr. Ludwig and I am hopeful that in due course they will be able to make a practical suggestion.

 I will certainly not rest easily until a simple method has been devised to prove the equation fluoridation = less fillings


(G.H. Leslie)


Division of Dental Health

 6) With this letter we have what amounts to a “smoking gun” as far as the inability of NZ  dental officials and researchers to show the effectiveness of fluoridation – some eight years into the ten-year Hastings-Napier fluoridation trial.

7) However, miraculously, two years later this trial was proclaimed as a great success at demonstrating that fluoridation had led to a large reduction in tooth decay (over 60%) and the result was used to push for fluoridation throughout the country.

8) So how in the space of two years was this dramatic turnaround achieved?

9) According to Dr. John Colquhoun’s research it was a complete artifact. The deception was in three parts. First, after about two years the control city of Napier was dropped for bogus reasons. Two, the reduction in tooth decay claimed was based on comparing tooth decay in Hastings at the beginning and the end of the trial (and not a comparison between tooth decay in Hastings and Napier).  Three, method of diagnosing tooth decay was changed during the trial. Colquhoun describes this third aspect of the deception:

The school dentists in the area of the experiment were instructed to change their method of diagnosing tooth decay, so that they recorded much less decay after fluoridation began. Before the experiment they had filled (and classified as “decayed”) teeth with any small catch on the surface, before it had penetrated the outer enamel layer. After the experiment began, they filled (and classified as “decayed”) only teeth with cavities, which penetrated the outer enamel layer. It is easy to see why a sudden drop in the numbers of “decayed and filled” teeth occurred. This change in method of diagnosis was not reported in any of the published accounts of the experiment.”

What qualifies these activities as scientific fraud, in my view, is the last sentence: “This change in method of diagnosis was not reported in any of the published accounts of the experiment.”

 10) To the best of my knowledge the evidence that Colquhoun and Mann put forward for this rigged trial has never been refuted. I would be anxious to see if Ken can throw a different light on this matter. If he can’t then I think that he and other NZ citizens should be concerned that the people of NZ were duped in this way.

Ken was unresponsive to many of my other concerns expressed in parts 1 and 1A (or parts 1 and 3 in my thread, The Arguments Against Fluoridation).

11) Ken didn’t address the key issue of the difference between concentration and dose when comparing artificially fluoridated communities and naturally fluoridated study communities when harm has been identified.

12) He didn’t address the need for a margin of safety calculation when determining a safe dose for a community based on a human study that has found harm (see chapter 20 in The Case Against Fluoride…). Nor did he comment on the sample margin of safety analysis that I provided based on the Xiang et al. (2003a,b) study, although he has commented on the Xiang study elsewhere.

13) He didn’t comment on my response to his claim – that there was no need to control the dose as far as efficacy was concerned because it worked over a wide range. I pointed out that there was not a wide range as far as safety was concerned and gave this information:

“I would also remind you that when the US National Research Council reviewed the toxicology of fluoride in water they concluded that several subsets of the US population were exceeding the US EPA’s safe reference dose for fluoride (the so-called IRIS value) of 0.06 mg/kg/day. This included high water consumers and bottle-fed infants. See Figure 2.8 in their report (NRC, 2006).”

14) Ken is ducking a key issue when he writes:

“It is pointless to continue debating definitions of fluoride as a medicine – as I have said the argument is largely semantic. People who wish to pursue the argument should do so in a court of law.”

Is he suggesting that in order to get a rational response from him on this matter I have to take him to court? Joking apart, surely he can concede that the purpose of fluoridation is to treat people as opposed to treating the water to make it safe or palatable to drink? And if he is willing to concede that then doesn’t treating people – at least in some countries – require that those treated have the right to informed consent to that treatment? This is not just about semantics it is about fundamental human rights.  See the definition of medicine and medical treatment under EU law which I provided in the other thread (part 6).

15) Instead of providing me with examples of statements from countries in Europe that have rejected fluoridation for reasons other than the two main ones I cited, Ken fobs me off with a statement from the NZ National Fluoride Information Service. In this statement this body gives no specific examples of countries that have not fluoridated for the reasons it – or Ken – states. So I will ask him again.

Ken please provide some evidence that countries have not fluoridated for the reasons you have given as opposed to the reasons I have given, namely: they do not wish to force fluoridation on people who don’t want it and they argue that there are unresolved health concerns about the practice.

16) When Ken restates that:

“For the vast majority of people who have dental fluorosis (recognised by a professional) it is usually classified as “questionable” or “mild.” Real health concerns should only be raised for severe dental fluorosis. Yet anti-fluoride activists lump all those grades together and pretend that dental fluorosis is a much bigger problem than it really is.”

Ken has essentially ignored all the information I provided for him on this issue. I provided the figures cited by the CDC (2010) for dental fluorosis for children aged 12 to 15 in the US. In this report, they indicate that very mild dental fluorosis impacts 28.5% and mild dental fluorosis impacts 8.6% of the population in question. Mild dental fluorosis affects up to 50% of the tooth surface and presents potential psychological problems for young teenagers. Ken may not consider that a “real” problem but many teenagers do. Ken might also be interested to know that Trendley Dean, the so-called father of fluoridation , who developed this first classification of dental fluorosis in the 1930s, in testimony before the US Congress stated that mild dental fluorosis was an unacceptable trade-off for reduction in tooth decay (see chapter 11 in The Case Against Fluoride…).

Moreover 3.6% of US children aged 12-15 have dental fluorosis in either the moderate or severe category. In these categories 100% of the enamel of the impacted teeth is impacted. Neither of these categories is desirable. 3.6% of all the children aged 12-15 in the US is a lot of children!

17) Ken also claimed that there was practically no difference in dental fluorosis prevalence between fluoridated and non-fluoridated communities. He ignored my response. I cited the study by Heller et al (1997), which clearly showed that that was not the case. They found that as the fluoride levels rose from a) less than 0.3 ppm, to b) 0.3 to 0.7 ppm , to c) 0.7 – 1.2 ppm and then d) above 1.2 ppm there was a marked increase in dental fluorosis rates.

18) I offered an animal study (Varner et al, 1998) in which rats were exposed to 1 ppm fluoride (administered either as AlF3 or NaF) for one year and experienced harmful effects.  I provided this reference because Ken stated that he paid no attention to animal studies performed at high concentrations and that was all he was offered by opponents of fluoridation. However, I got another brush off from Ken.  He claimed that he couldn’t find the whole study by Varner et al – only the abstract – and after a few words on the abstract then stated, “I won’t comment further on this.” First, of all I am surprised that no University in the Hamilton area carries the journal Brain Research where the Varner paper appeared. Also if Ken was having trouble finding this all he had to do was email me and I would have forwarded him a pdf copy of this paper. For future reference I would be happy to do that for all the papers I cite.

19) Nor did Ken respond to the discussion in which I pointed out that the US Food and Drug Administration classifies fluoride for ingestion as an “unapproved drug.” This means that in the U.S. fluoride intended for ingestion has never been subjected to the double blind randomized control trials (RCT) for efficacy that are required of all other drugs. Nor is the FDA tracking side effects from patients or doctors, despite the fact that many individuals claim to be highly sensitive to fluoride’s toxic effects. The same professional and regulatory neglect appears to have occurred in all other fluoridated countries, including New Zealand.

Note: I have raised more specific questions about this professional and regulatory neglect in my latest response (part 6) in the other thread.

20) Ken claimed (in part 2 of this thread) that there was no difference between naturally fluoridated water and artificially fluoridated water and I responded in part 3 that:

“Usually when fluoride occurs naturally in the water it is accompanied by large concentrations of ions like calcium. The presence of the calcium can reduce the uptake of fluoride in the stomach and GI tract. No such protection is offered when the fluoridating chemicals are added to soft water.”

Ken did not acknowledge this important difference.

21) In my response (part 3 of this thread) I wrote:

“In my opening statement I singled out three subsets of the population that shouldn’t be getting fluoridated water: bottle-fed babies, people with poor kidney function and people with outright or borderline iodine deficiency. Ken chose not to comment on the latter two groups. In my view we should be concerned about both groups whether they are drinking naturally occurring fluoride or artificially fluoridated water.”

For the second time Ken chose not to respond to these concerns. Ken is certainly very sensitive to the treatment of low-income families because of his own personal history but he seems not to be as sensitive to the fate of these subsets of the population.

22) Ken chose not to respond to this question:

“Is it not reckless then to knowingly expose the bottle-fed baby to 175-300 times more fluoride than the breast-fed baby? Especially, when we know that fluoride can harm at least one developing tissue in the baby – the growing tooth cells – at very low levels and cause the condition known as dental fluorosis.  What makes us believe that while the fluoride is damaging processes in the growing tooth it is not doing the same to the growing bone. After all the teeth grow out of the bone.”

23) Ken chose not to respond to the following information:

“Even when some warning signals emerged during the early trials they were cavalierly ignored by those hell-bent on promoting this practice. For example, when Schlesinger et al., 1956, published the results of the Newburgh-Kingston trial in 1956 they reported that young girls in the fluoridated community were menstruating 5 months earlier on average than the girls in the non-fluoridated community, and that the young boys were experiencing about twice as many cortical bone defects in the fluoridated community compared with the non-fluoridated community. However, no follow-up studies were recommended (see Chapters 9 and 10, The Case Against Fluoride…). These red flags were ignored then just as the studies indicating a lowering of IQ associated with fairly modest levels of fluoride exposure, are being ignored or downplayed by proponents today.”

24) Ken chose not to respond to Dr. Hardy Limeback’s discussion of possible ways that fluoride can interfere with normal bone growth:

“Bone can ACCUMULATE up to 2500 ppm fluoride with fluoridation (we showed that in our Toronto vs Montreal study). The osteoclast cells are exposed to these huge concentrations (because they dissolve bone keeping the dissolved mineral under their dorsal surface through the use of hemidesmosome attachments and then they release that dissolved mineral into the bone extracellular fluid where nearby osteoblasts can also be exposed). In fact one of the theories why there is apoptosis of osteoclasts is the poisonous conditions they have to endure remodeling bone. It is also the reason there is a biologically-supported rationale for the bone cancer inducing effects of fluoride (personal correspondence, Nov 1, 2013).”

Now I will attempt to respond to some of the issues that Ken did comment on.

25) I agree with Ken that I was a little hasty in dismissing the Irish data comparing tooth decay in the Republic of Ireland and Northern Ireland. However, the larger point I was making was this: if indeed it is legitimate to compare these two populations (and there are both cultural and genetic differences) then the more urgent need is to compare the status of various health concerns – which may or may not be caused by or exacerbated by fluoride – between the two countries. However, even though fluoridation has been mandatory in the Republic since 1963, the health authorities there have not attempted a single study comparing the health of communities which are fluoridated and non-fluoridated, either within the Republic itself or between the Republic and the North. Like most fluoridated countries (including NZ) they are flying blind on health concerns.

26) I think the value of comparing tooth decay between countries is to note that tooth decay rates have been coming down in both fluoridated and non-fluoridated countries at similar rates. Avid promoters of fluoridation such as the Oral Health Division of the CDC often forget this and try to claim that fluoridation has been coming down in fluoridated countries because of fluoridation when similar declines have occurred in non-fluoridated countries over the same period. See the CDC’s ridiculous Figure 1 in CDC (1999),  (see figure below) which purports to show that tooth decay in 12-year olds has come down in the US over the period 1960s to the 1990s because over the same period the percentage of the US population drinking fluoridated water has increased!

Fig1 connett I urge readers to compare this CDC figure with the figure summarizing the decline in tooth decay in many different countries – both fluoridated and non-fluoridated countries – covering the same period (and beyond) cited by the CDC.

fig2 connett

27) I agree with Ken that whenever we cite the CDC (1999) statement that fluoride’s predominant mode of action is topical not systemic we should not omit the word predominant. I usually do this. He found one example when I didn’t.

28) I have conceded in another post that I was wrong in suggesting that Ken believed that the delivery of fluoride’s topical effect was via the saliva generated in the salivary gland. However, if Ken rules out a significant role for the fluoride delivered by the salivary gland, and instead that the topical action is delivered directly in the mouth, why are we forcing people to swallow fluoridated water at all? Especially adults where no tooth development is involved once their teeth have erupted? Why instead, is he not merely advocating swishing and spitting out fluoridated water, or fluoridated mouthwash or using fluoridated toothpaste.

30) In challenging Ken’s notion that the only animal studies we quoted had very high fluoride levels. I responded that it was well known that you needed to treat rats with 5 to 10 times as much fluoride to reach the same plasma levels as humans.  Ken responded by pointing out he could find only one reference to this and cited the NRC (2006) commentary on Dunipace’s work (Dunipace, 1995). The NRC characterized Dunipace’s conclusion as showing that “rats require about five times greater water concentrations than humans to reach the same plasma concentration.” (Appendix D, p. 442). However, there are several other studies that have suggested the same or even a higher ratio than 5 is needed.

Sawan (2010) explains why he used 100 ppm in his animal experiment as follows:

“However, while the fluoride concentration used in the present could be considered relatively high for rodents (100 mg/L or ppm), this concentration was chosen because it produces plasma fluoride levels that are comparable with those commonly found in humans chronically exposed to 8mg/L of fluoride in the drinking water, which is a concentration known to cause severe fluorosis.”

That is a ratio of 12.5.

Also Angmar-Månsson and Whitford (1982) pointed out to produce enamel fluorosis in rats one needed a concentration of 10 to 25 ppm fluoride (compared to the 2 ppm needed in humans). So that means you need a ratio of 5 to 10+ more fluoride to get the same result in rats as humans.  Here is the quote:

“It is well known that, in fluoridated drinking water studies with rats, a water fluoride concentration of 10 – 25 ppm is necessary to produce minimal disturbances in enamel mineralization. Because of the higher water concentrations required, the rat has been regarded as more resistant to this adverse effect of fluoride. However, when the associated plasma levels are considered, the rat and the human appear to develop enamel fluorosis at very nearly the same fluoride concentrations.”

I would also point out that, in addition to the extra amount needed to reach the same plasma levels in humans, the NRC pointed out in their 2006 report that rats need at least 10 times more fluoride than humans to reach the same bone fluoride levels. To quote:

” …values support a rat-to-human conversion factor for bone fluoride uptake of at least an order of magnitude.” (Appendix D, p. 445)

Dr. J. William Hirzy.

31) Ken uses dentist Steve Slott to categorize Dr. Hirzy in the following manner, “Hirzy is a long time avowed antifluoridationist and is employed by Connett as the paid lobbyist for Connett’s antifluoridationist group, FAN.”

Clearly this comment from Slott, “an avowed profluoridationist,” is meant to throw doubt on the credentials and integrity of my colleague Bill Hirzy. I have known Bill for over 15 years. I first met him when he was working at the US EPA. At that time he and other professionals at the EPA were very concerned about the way that administrators in this agency felt that it was OK to force professionals to “bend their science and their statements” to fit into their policy judgments.

This concern began in 1985 when a scientist at the EPA admitted that he had been forced to go along with a determination that the safe MCL for fluoride was 4 ppm, when he knew that this level wasn’t safe. This professional and others at the EPA knew that the administrators were bowing to political pressure from politicians (e.g. Strom Thurmond) in certain states with areas of high natural fluoride and who were concerned that if a lower level was set for the MCL it would cost their states a lot of money to remove the fluoride.

As a result of this Dr Robert Carton and others set up a union at the EPA headquarters in an attempt to get a code of scientific integrity adopted at the EPA. This would forbid administrative staff from forcing scientists to make false statements about their scientific findings in order to fit into the “policy” of administrators. This same union after examining the scientific evidence came out in strong opposition to the so-called safety of the MCL and the MCLG for fluoride, both of which had been set at 4 ppm, and also the practice of water fluoridation.

Those who are interested can view Dr. Hirzy’s statement before a Senate subcommittee in the US Congress in 2000 (http://fluoridealert.org/fan-tv/hirzy/ ). Clearly, Bill’s opposition to fluoridation is science-based. Moreover, in a democracy like the US, like any other citizen, including Steve Slott, he is entitled to his opinion on a public policy issue like this, without being treated like some paid hack.

When Bill retired from his teaching position, Fluoride Action Network was only too happy to have such a qualified person work as our point person in Washington, DC. We have paid him a nominal salary to do this. That shouldn’t be used to suggest that he has somehow thrown science and his integrity out of the window, which I think Slott meant to imply when he says Bill is a “paid lobbyist for Connett’s antifluoridationist group, FAN.” Based on the science Bill is opposed to fluoridation. Based on the science FAN is opposed to fluoridation. It is a shame that Slott should think – or intimate – otherwise.

As far as lobbyists are concerned I think Steve would do better to wonder what the ADA is doing with 20 paid staff in DC, all of which are receiving a remuneration, which makes Bill’s nominal salary look like a pittance. One of the things that ADA is doing with its $100 million budget is to try to persuade Congress and state health departments not to allow dental therapists to perform basic dental procedures in low-income areas. Ironically, I believe that Steve is against the ADA’s position on this sensible and cost-effective measure. It has proved most successful in NZ.

In my view Bill Hirzy is an excellent educator on this and other issues. We believe that he can help with a lot of education in Washington, DC, not just with legislators but with the city council and with environmental and other public interest groups.  A lot of people in DC respect both his experience and his integrity.

Here is the link to Bill’s correction of the errors in his arsenic paper:


32) Finally, I attach Dr. Hirzy’s response to Ken’s comments on his input in part 3 of this thread:

In a paragraph headed in bold type Perrott cites my activism as reason to question my ability to properly assess risks. I freely admit making an error (soon to be rectified by publication of a corrigendum) in the annual cancer incidences for HFSA and pharmaceutical sodium fluoride. That said, nevertheless EPA did not find fault in my determination that HFSA causes about 100 times more cancer than pharmaceutical sodium fluoride. Neither does Perrott show any fault in that determination.

Perrott comments about my dismissal of NSF’s statement about their testing allegedly proving the amount of arsenic contributed by HFSA is non-detectable and perfectly safe, but he fails to address my observation that NSF in fact reports measurable amounts of arsenic contributed by treatment chemicals, and that those levels lead to 200 times higher cancer risk than USP NaF. In a debate one should address points raised by one’s opponent – if one can…..

After doing some calculations based on the New Zealand Specific Impurity Limit for arsenic, I do admit that the New Zealand standard is superior by a factor of 2.4 to that of NSF.  That is, however, faint praise in that it allows about 500 fold higher lung/bladder cancer incidence than pharmaceutical grade sodium fluoride. See below.

Regarding the arsenic levels in HFSA and Mr. Perrott’s being “suspicious” about my results and whether the HFSA samples I reported on were representative, Mr. Perrott cites the Brown et al. 2004 publication in the Journal of the American Water Works Association and kindly provided a link to the article. If he had read that article closely he would have noticed the support for my work on page 118. At page 118 of that piece, Brown et al. report testing 4 samples of HFSA, rejecting one because of excessive free HF, and finding arsenic levels of 9, 20 and 47 mg/kg, in the other three samples, all of which values fall within the range of the 33 samples I cited in my statistical analysis of arsenic levels in HFSA. Further on page 118, Brown et al. cite results from Weng et al. reporting on an unstated number of HFSA samples, finding an average of 28 mg/L and a maximum of 60 mg/L of arsenic – again within the range of my analysis. Finally, also on page 118 is citation of work by Casale, who found a range of 9.4 to 58.5 mg/L of arsenic – within the range of my analysis.

Concerning activism and suspicion, perhaps Perrott is correct in asserting that higher purity HFSA is available in New Zealand, but his activism in promoting  fluoridation could raise parallel suspicion about that.

Perrott dismisses as “a silly conspiracy theory” my recitation of data published by the U.S. Geological Survey (USGS) showing that 94% of the byproduct HFSA produced by phosphate manufacturers in 2011 was sold to water fluoridation systems, and coupled with solid data on sales prices, produced about $560,000,000 in revenues for those companies. If only 6% of HFSA found alternative markets, which USGS found to be valued by the producers at nearly double the value for the fluoridation market, where else would HFSA go than down our shower drains and toilets, etc. Pretty good business model for a “silly conspiracy” I’d say.

My citation of the violation in Wellington, Florida was the only one I knew about. How many more there may be/have been, who can tell? And why are HFSA producers not routinely supplying certificates of analysis for every batch sold rather than simply stating “Complies with NSF/ANSI Standard 60.”

What New Zealand Might Otherwise Do (Based in part on Standard for the Supply of Fluoride for Use in Water Treatment – Second Edition. New Zealand Water Supply and Disposal Association. 1997)

Assume density of 20% assay HFSA is 1.2 g/mL  (density of 24% assay is 1.24g/mL).

Pure HFSA is 79% w/w fluoride

1 mL of HFSA  x  1.2 g/mL  x  0.20  x .79 = 0.190 g F/mL HFSA = 190 mg F/mL HFSA

Assume need to add 0.50 mg F/L H2O

0.50 mg F/L H2O ÷ 190 mg F/mL HFSA = 2.6 x 10-3 mL HFSA/L H2O

2.6 x 10-3 mL HFSA/L H2O x 1.2 g HFSA/mL HFSA = 3.2 x 10-3 g HFSA = 3.2 x 10-6 kg HFSA/L H2O

SIL for As = 132 mg As/kg HFSA

1.32 x 102 mg As/kg HFSA  x  3.2 x 10-6 kg HFSA/L H2O  = 4.2 x 10-4 mg As/L = 0.42 ug As/L

Using the USEPA modified population Unit Risk value of 3.5 x 10-5/(ug As/L), a risk for lung/bladder cancer of 1.5 x 10-5 obtains. This is equivalent to 15 extra cancers per million population exposed for 70 years.

If 4 million people have been exposed at this level for 20 years, one would expect about 17 extra cancers to have developed.\

New Zealand’s SIL for arsenic is about 2.4 times more protective than the U.S. standard.

If pharmaceutical grade NaF had been used for this same period, delivering 0.00084 ug As/L, then New Zealand’s 4 million people exposed for 20 years may have developed about 0.03 such cancers.

If the New Zealand government were to have provided 4 million people with 2 L/day of water containing 0.50 mg added fluoride from pharmaceutical grade NaF for 20 years (and it is very likely that far fewer than 4 million would have opted to drink that water), it would have spend, in constant 2001 U.S. dollars, about $190,000.

If HFSA had been purchased at about half the price charged in the U.S., i.e $800/metric ton over that same period, and assuming New Zealanders use half as much water per capita as U.S. citizens, i.e. 50 U.S. gallons/day, and this practice ran for 20 years, then about $6,000,000 would have gone to phosphate producers.

And assuming it costs half as much in New Zealand to treat the cancers HFSA’s arsenic load produced, then an additional $30,000,000 would be spent on medical costs.\

So, if you are really determined to offer fluoridated drinking water to New Zealanders, you would be well advised to consider the substantial cost savings you would realize by providing free containers of water fluoridated with pharmaceutical grade NaF just to those who want it, while acceding to the demands of your citizens who most vehemently do not want fluoride in their drinking water.\

And, by the way, the New Zealand Lung and Bladder Cancer/Fluoridation Lottery could be cancelled too.  

Postscript. This will be my last contribution to this thread. I feel that I have presented my case fully in the book I co-authored (The Case Against Fluoride…). What I am more interested in now – having outlined some basic arguments against fluoridation in this thread (few of which have been satisfactorily rebutted) – is seeing what scientific case Ken can produce for fluoridation. This is meant to be the substance of the other thread and that is where I will now focus my efforts.

In this respect I have been disappointed in Ken’s ability – after four attempts to do so –including the last installment that he published yesterday (Dec 10) – to lay out a scientific case. So far Ken seems more adept at theorizing on why drinking fluoride should work rather than providing the studies that it actually does. In addition, he spends more time demonstrating his disdain for anyone opposed to fluoridation than actually producing the science which shows that fluoridation is “safe and effective” as proponents repeatedly claim. Finding fault with me or other opponents does not establish a case FOR fluoridation. It is a practice forced on millions of people that don’t want it. He defends this practice and as such it his obligation to present a scientific case FOR fluoridation and I am still hoping that he will do that.

Let me be more specific: what I had hoped to see by now is:

a) What primary scientific research Ken has read that gives him the confidence  that the epidemiological evidence is overwhelmingly in favor of fluoridation providing a significant benefit over and above the use of fluoridated toothpaste.

b) What his response is to the latest news from Scotland that a simple and cost-effective strategy has been devised that has been found to combat tooth decay in low-income children which does not involve forcing people to swallow fluoride who don’t want to.

c) A presentation of a weight of evidence analysis that would allow him and other promoters to dismiss all the concerns I have raised about fluoride’s impact on the brain and several other tissues.  We have presented this case in our book and again in both these threads. Our case is in black and white and documented, where is his response in black and white and documented?

In the process of doing this I would particularly would like to see him identify papers that have been conducted in NZ (or Australia for that matter), which have examined any of the health issues discussed in our book, or that have collected fluoride exposure levels in the urine, blood or bones of NZ citizens to gauge their exposure to fluoride both in the short-term or long-term. In other words I am anxious to find out:

a) the scientific basis for his confidence in the safety of water fluoridation;

b) the argument he would raise to support the notion – despite so many unknowns – that the practice does not violate the Precautionary Principle (see chapter 20 in our book and Tickner and Coffin, 2006), and

c) the basis for his confidence that there is an adequate margin of safety (see chapter 21 in our book) to protect everyone in a large population drinking fluoridated water – especially the most vulnerable – from any harmful effect.

I will continue to pursue his response to these challenges in the other thread: Ken’s Arguments For Fluoridation.


 Angmar-Månsson B, Whitford GM. (1982). Plasma fluoride levels and enamel fluorosis in the rat. Caries Res. 1982;16(4):334-9.

CDC (1999). Centers for Disease Control and Prevention, “Achievements in Public Health, 1900–1999: Fluoridation of Drinking Water to Prevent Dental Caries,” Mortality and Morbidity Weekly Review 48, no. 41 (October 22, 1999): 933–40, http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4841a1.htm

CDC (2010). Beltrán-Aguilar, D et al., Prevalence and Severity of Dental Fluorosis in the United States, 1999-2004. MMWR, 53; November. http://www.cdc.gov/nchs/data/databriefs/db53.htm

Colquhoun J. and R. Mann (1986). “The Hastings Fluoridation Experiment: Science or Swindle?” The Ecologist 16, no. 6: 243–48.

Colquhoun, J (1987). Education and Fluoridation in New Zealand: An Historical Study,” Ph.D. diss., University of Auckland, New Zealand.

Colquhoun J. and B. Wilson (1999). “The Lost Control and Other Mysteries: Further Revelations on New Zealand’s Fluoridation Trial,” Accountability in Research 6, no. 4:373–94.

Connett, P., Beck, J and Micklem HS. The Case Against Fluoride. Chelsea Green, White River Junction, Vermont, 2010.

Dunipace AJ, et al. (1995). Effect of aging on animal response to chronic fluoride exposure. Journal of Dental Research 74(1):358-68.

Heller KE, et al. (1997).“Dental Caries and Dental Fluorosis at

Varying Water Fluoride Concentrations,” Journal of Public Health Dentistry 57, no. 3: 136–43.

Hirzy (2000). Video. http://fluoridealert.org/fan-tv/hirzy/

NRC (2006). Fluoride in Drinking Water: A Scientific Review of EPA’s Standards (2006) http://www.nap.edu/catalog.php?record_id=11571

Sawan RM, et al. (2010). Fluoride increases lead concentrations in whole blood and in calcified tissues from lead-exposed rats. Toxicology 271(1-2):21-6.

Schlesinger ER, et al. (1956) “Newburgh-Kingston Caries-Fluorine Study XIII. Pediatric Findings After Ten Years,” Journal of the American Dental Association 52, no. 3: 296–306.

Slade, G.D., A.J. Spencer, et al. (1996). “Caries experience among children in fluoridated Townsville and unfluoridated Brisbane.” Aust N Z J Public Health 20(6): 623-9.

Tickner, J and M. Coffin (2006). “What Does the Precautionary Principle Mean for Evidence-Based Dentistry?” Journal of Evidence Based Dental Practice 6, no. 1: 6–15.

Varner et al. (1998).“Chronic Administration of Aluminum-Fluoride or Sodium-Fluoride to Rats in Drinking Water: Alterations in

Neuronal and Cerebrovascular Integrity,” Brain Research 784, no. 1–2: 284–98.

Xiang, Q et al. (2003a) “Effect of Fluoride in Drinking Water on Children’s Intelligence,” Fluoride 36, no. 2 (2003): 84–94, http://www.fluorideresearch.org/362/files/FJ2003_v36_n2_p84-94.pdf

Xiang, Q et al.(2003b), “Blood Lead of Children in Wamiao-Xinhuai Intelligence Study” (letter), Fluoride 36, no. 3 (2003):198–99, http://www.fluorideresearch.org/363/files/FJ2003_v36_n3_p198-199.pdf

Anyone wanting to follow the debate and/or check back over previous articles in the debate can find the list of articles at Fluoride Debate.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page

Fluoride debate: Response to Paul’s 6th article.

This is Ken Perrott’s response to Paul Connett’s last article Fluoridation debate: Against Fluoridation Thread. Part 6.

For Paul Connett’s original article see – Fluoride debate Part 1: Connett.

Discussion in comments section: The quality of the discussion in the comments section accompanying this exchange impresses me. We have kept out the trouble makers who generally dog this issue and this blog by moderation. But the level of knowledge and familiarity with the scientific literature of commenters is higher than is usual. Most of Paul Connett’s associates at his organisation Fluoride Alert are contributing and many of the commenters have a background in relevant professions.

So I urge readers to dip into these comments. Yes, there are a large number and it can get confusing. But some of the issue discussed in the exchange are thrashed out in greater detail in the comments. You will find useful information and arguments presented, as well as helpful literature citations.

In his last article Paul adopted an approach of attack and discredit and did not deal with most of the issue I raised. He continues to ignore, or even downplay, issues like the normal role of fluoride in bioapatites, the recognised systemic benefits of fluoride, the poor quality or inappropriateness of many of the studies he relies on (and of the journal Fluoride he promotes). This is accompanied by an attack on a broad front where he poses no less than 10 questions he demands answers to.

I had expected he would be raising his issues in a more detailed way, one at a time. Laying out his arguments and evidence. But in one go he has thrown them all into the ring without any preparation. It’s a real Gish gallop – suddenly demanding answers about arthritis, kidney function, thyroid function, osteosarcoma, individual sensitivity to fluoride, menstruation, effect on babies, monitoring bone concentrations and finally, all or any health concerns in New Zealand. Without any background to any of the issues.  (Wikipedia describes Gish gallopers as using “a rapid-fire approach during a debate, presenting arguments and changing topics quickly).

Is Paul “going for broke?” It looks like a military exercise but I wonder what military experts would think of the tactics he is using.

Obviously I am not going to walk into the trap of fighting on so many ill-defined fronts. But Paul has at least defined 3 key areas he expects to be tackled – ethics, efficacy and safety. I will restrict my response to these but add some general comments on the nature of science which I think need to be made. But please, note – I am not avoiding those questions – let’s deal with them in a proper way where we have the context and background.

Readers may also see that some of these questions are being discussed and answered in the comments section.


I am pleased Paul gave such a prominent role to ethics in his last article but disappointed he reduces the ethical aspects to simply his wish to define fluoridated water as a medicine. If that exhausted the ethical aspects the discussion would now be over as no court has accepted this definition in a final way. A Pennsylvanian anti-fluoridation group ActionaPA.org even laments:

“While the courts have acknowledged that fluoridated chemicals are hazardous, the courts have overwhelmingly ruled in favor of water fluoridation whenever the courts were asked to rule on the merits of fluoridation or on the right of government to fluoridate. The courts have consistently brushed aside the scientific and ethical matters raised by safe drinking water advocates, while deferring to the opinions of pro-fluoridation state authorities. These decisions have formed a body of case law so one-sided that the courts have allowed this momentum to justify further pro-fluoridation decisions.”

Paul will correct me if I am wrong – although I would have expected he would already have mentioned any decision favouring his argument. The fact that he hasn’t is telling.

Legal definitions and legal actions

Bill Osmunsen (the West Coast Spokesman for Paul Connett’s activist organisation Fluoride Alert) vigorously pushed the “fluoridation as a medicine’ argument in the comments sections of this exchange. Paul works closely with him and James Robert Deal who runs the organisation Fluoride Class Action which aims to achieve a legal ruling declaring fluoridation illegal. So I expect Paul would know of any final ruling declaring fluoridation a medicine. (James has also been contributing to the discussion in the comments sections).

Bill was  unable to give a clear example of any regulations which define fluoridation as a medicine. Despite this, and the lack of any legal support, this is a common argument used by anti-fluoridation activists. In the end it relies on circuitous interpretations of regulations and a certain degree of handwaving . I don’t propose discussing it further here – except to comment on a recent use of this argument by anti-fluoridation activists in the NZ High Court. This shows how such legal action can play a legal role, even where chances of legal success are remote.

The Hamilton City Council recently voted to defer an expected decision to restore fluoridation to the city after an overwhelming referendum result showing voters wanted it. The reason for deferral was to await the High Court decision on the case taken by the NZ Health Trust who argue the South Taranaki Council is breaking the law and breaching the New Zealand Bill of Rights Act by adding a substance they claim is akin to a medicine to the water supply. Some Hamilton Councillors were swayed by arguments that similar action could impose high costs on their own council.

Institutions and bureaucrats are easily pressured by legal action – even just the threat of legal action. Several time in my research career managers prevented me from publishing research findings on some products because the distributors who didn’t like the findings threatened legal action if the data were published. I can see similar things happening here as the Taranaki High Court decision will most probably be unfavourable to the Trust and it will appeal. Such a process could go on for several years. Meanwhile other councils, and even individual councillors, will feel intimated by similar threats of possible legal action.

Ironically the NZ Health Trust has been very active in fighting any legislation for regulating natural health products because they do not wish to see these products classified as drugs. And here they are attempting to argue that fluoridated water is a drug! The Trust is also active on issues such as Chemtrails, vaccinations, opposition to conventional health, etc. in effect they are advocating for people with some very whaky ideas as well as for the alternative health and medicine industry which is quite a big business in New Zealand. In a recent Listener review Sally Blundell described the vitamin and natural supplement sector as a  US$34 billion business (see The final vitamin question). Add the alternative health practitioners and we can get an idea of the commercial forces behind the anti-fluoridation movement.

Another organisation threatening legal action is Fluoridegate legal action NZ. This is an obvious astroturf organisation for the local Fluoride Action Network of NZ (FANNZ). Like the other astroturf organisation the New Zealand Fluoride Information Service they operate out of the same address as FANNZ and are used in letter writing campaigns and  press releases.

Balancing personal choise and social good.

Most anti-fluoridation articles and propaganda just don’t attempt this balance. At most they might stress the need for individual freedom of choice but give social good a miss. Usually ethical considerations are limited to arguments around the concept of fluoridated water as a drug or medicine, as Paul has done.

More serious authors do consider ethics as basically about this balance. In principle one could consider this balance as represented in values and political attitudes. But in practice this is often distracted by appeal to scientific claims, even scientific misinformation. Some ethicists, whose understanding of the science may be rudimentary and/or distorted sometimes allow this poor knowledge to distort their ethical calculations  and conclusions.

In the day-to-day political debate such scientific misinformation regularly diverts ethical discussions. In the words of Prof Gluckman in his article What is in the water?:

“The misuse or inappropriate and alarmist use of science is a classic example of science being a proxy for values debates.”

It is a difficult issue because while science cannot make values decisions for us, such values considerations need to be informed by the science. And if they are informed by bad science there is a good chance the ethical conclusions will be wrong.

In my experience debating opponents of fluoridation it is easy to get them to agree decisions like this are political- or values-based but in the ensuing discussion they find it very hard to argue out the values issues. Very often the discussions end up being about the correctness of a scientific claim they make. The science proxy takes over and the real issues are ignored.

Why is this? In many cases I think anti-fluoridation activists have not thought the ethical questions through completely. They have got stuck on the “fluoridated water is a drug” or “personal choice” arguments and have never really considered the social good aspect in any depth. So as soon as they feel challenged on the ethics they will resort to using scientific misinformation – dragging in a proxy.

In other cases I have heard a few fluoridation opponents stick to the ethical argument. Refuse to discuss the science and declare that for them it is just about personal choice. This is more honest – but again it is hard to get into the social good aspects because these people usually just don’t want to even consider it, or even denigrate the very idea. Often these people will declare they are libertarian in their political outlook.

Possibly in the end that is what the issue reduces to – one’s political/values outlook. Not a scientific issue resolvable by research and often not even resolvable by reason and logic. Emotion inevitably plays a large part in such values. In a democratic society these issues have to be resolved (if only in the short-term) by transparent consultation and referenda with the minority accepting majority decisions. It is immature not to accept that.

As social animals we are always balancing social issues against personal ones. It is part of living in a social group. I believe that to stress only one aspect is the mark of an extremist. Most people are happy to accept a democratic decision on the balance.

It is disingenuous to see a decision about social good amounting to the minority having something forced on them. As a society we support free public hospitals and secular schools. A minority refuse to use these facilities and they are not forced to. They can make their own arrangements and many do. Private schools and private healthcare is common. The cost for people who wish to opt out of the community water supply is surely minor compared with education and hospitals.

Fluoride sensitivity?

Another common argument relates to the claimed 1% (or 3%) of the population who are supposedly over sensitive to fluoride and suffer all sorts of symptoms when water is fluoridated. I am happy to concede there may be a small number of people like this – as for other common chemicals in the environment. Frustratingly, the evidence for fluoride sensitivity usually comes from unavailable old papers or very poor research (as Paul’s citations are) or (most often) personal anecdote. At least some of these personal anecdotes may be honest-but-psychological as a study of the persistence of symptoms when residents were told that fluoridation existed even though it had stopped shows (see Fluoride sensitivity – all in the mind?. Frankly, I think at least some of these anecdotal claims are really politically motivated – they often come up when local councils hear submissions from anti-fluoridation activists and are not supported by medical assessment. These appeals rely solely on emotion and empathy.

Those people with a genuine sensitivity to common (and often naturally occurring) chemicals in our environment face us with that balance issue. To what extent should society deny itself something beneficial to protect the interests of a very small minority? Very often society does decide that such small groups of people must take responsibility for their own condition and handle their own requirements. Maybe the most empathetic solution is that society as a whole compensate this small number of people in some way to aid them with their predicament.

Social health policy

Finally, I think many people just don’t have a concept about the nature of social health policies? Or the benefits they bring to society as a whole.

Declaring that people should add their own fluoride to their water, learn how to brush their teeth, etc., ignore the reality of life for so many socially and economically challenged families and their children. Choices like this often cannot be made, or even thought about. (Let’s face it –  this is also very often the case with those who are not socially or economically disadvantaged). A social health policy like fluoridated water or salt, and iodised salt, works with such people (in fact with most people) precisely because it requires no action on their part.

Simple declarations that we should not have to bear a financial responsibility for those who are not responsible enough to care for themselves and their children gets into “cutting of noses to spite faces” territory. It is in the best interests, financially and socially, of all of us that children do not grow up disadvantaged by poor oral health. It is these children who will in future be paying the taxes to support us in our old age, and providing the services and goods we consume. Let us make sure, even from a purely selfish point of view, that these children grow up to become good citizens with fulfilled lives and the skills and education necessary for this.

Surely it is ideologically extreme to not accept this logic?

Real world science

Paul is a political polemicist, certainly not a scientist, when he demands the knowingly impossible.

He wants studies showing that fluoride “is not increasing the risk of arthritis,” “causes no damage to individuals with impaired kidney function” and “is not increasing the risk of lowered thyroid function.” He asks for scientific evidence indicating “that fluoride is not a neurotoxicant.” And, of course, when I don’t produce the impossible proof of a negative he, and his fellow anti-fluoridation activists, respond by taking this as “proof” that their claims are true. Are somehow proven! If only science was that easy.

“There could be a problem, so prove that there is not” is a fallacious tactic (see The negative proof fallacy) that has come up again and again in the comments discussion and I probably can’t do better that quote from Steve Stott’s patient replies:

“Requiring proof of a negative is an endless process which is not valid science.” “It is impossible to prove every conceivable, unsubstantiated contingency that anyone, anywhere can put forth. Valid evidence that a problem exists must be provided before credibly demanding proof that it does not.”

Isn’t this argument for negative proof the same as the tactic we have become very familiar with from creationists in their attacks on evolution?

Paul’s characterisation of the lack of randomised controlled trials (RCT) and the poor quality of much of the research in this area as problems only for supporters of fluoridation is similarly a political trick. These issues are ones for science in general. Science does not differentiate between supporters and opponents. The opponents of fluoridation are just as plagued as the supporters by the lack of RCTs and the poor quality of many published papers. It is their “fault” as much as that of supporters that there are insufficient research reports on this area of interest. If in fact these are genuine problems for all of us – why blame them only on proponents of fluoridation? That is a political, not a scientific, tactic.

After all, anti-fluoridation opponents keep telling me they have science on their side, they have the support of most scientists on their stance and they keep providing me supportive quotes from Nobel Laureates and “top scientists.” Shouldn’t they be levelling these criticisms at the anti-fluoridation scientists and researchers who they believe are so numerous? Or are these charges an admission of the falseness or irrelevance of their claims?

Paul’s own responsibility

More directly, Paul claims to have been researching fluoride for 17 or 18 years. He promotes his book as the last word on the subject and compulsory reading for anyone wishing to comment in this area. Many anti-fluoridation activists describe Paul as the world’s top expert on fluoride. He makes submissions  to community hearings on fluoridation – often by video link from the other side of the world.

So why is he not taking some responsibility for the lack of RCTs? What has he done to plan or put such trials into action? Why does he blame others for apparent lack of research. Surely if he in his wisdom had deemed such research necessary he would have been one of the first researchers to propose, plan and carry out the research?

Come to think of it – with such a reputation it is reasonable to expect a body of publications in reputable peer-reviewed scientific journals. My simple searching does not show any, although he does list 2 which I could not find on-line in a recent CV. Could Paul give us a relevant publication list? And links to the papers?

Is Paul’s judgement of the research too harsh?

Both sides should be pointing out the real world problems we face as scientists. Humans can not be treated as laboratory subjects. We cannot realistically segregate a population to the degree required for randomised double-blind studies because of all the confounding factors and the halo effect. This it is a problem for both opponents and proponents of fluoridation. It is dishonest to pretend that one side is being devious or avoiding the issue. Rather than making such charges people should consider the evidence that does exist (and this does include the randomised double-blind study of Stephen et al (1984) which showed beneficial effects of fluoridated milk on oral health – see Five-year double-blind fluoridated milk study in Scotland).

I often feel the York review was a little harsh to stress the poor quality of some of the available research on fluoride. Genuine science must work with the world as it is. It gets by with epidemiological studies where ideal controlled studies are impossible or too difficult. Scientific knowledge is always provisional, open to improvement as new data and findings come in. Scientific inference on safety and efficacy uses existing information and is not put off until the impossible final experiment can be done. Humans are used to operating in this way, of accepting there will always be some areas of incomplete knowledge, some untied strings, some small doubts and some future work to do. In that sense it is just political disingenuousness to promote the slogan “if in doubt leave it out.” Or to demand, as many anti-fluoridation activists do, that there should be no fluoridation until every scientific i is dotted and every t crossed. There is always some degree of doubt and the final is and ts are never dotted and crossed.

Citation battles

When science-oriented people debate controversial issues I sometimes feel I am in the middle of an intense citation battle. Each side throws our references claiming they support their position. Often they accompany the reference by a brief quote. It’s like an intense battle using barrages of paper darts or a game of citation tennis.

This is aimed at establishing credibility – but does it? I suspect more often than not it turns people off – especially those unfamiliar with the literature. And when those that are familiar retaliate with their own brief quote and citation to clarify it is just seen as part of a citation war.

People need to calm down, stop throwing around citations and quotes in this manner and calmly look in detail and context at the real scientific findings. Yes, unfortunately, this usually requires access to the full text of papers and not just using Google with a good dose of confirmation bias.

So, I am not impressed by Connett’s paragraph of about 30 unexplained citations – nor by a long reference list at the end of his article. I am not impressed by the way that anti-fluoridation activists often throw around citations they have never read – or if they have, not past the abstract. Usually they are just copied and pasted from Fluoride Alert without any critical consideration at all. No wonder some of us look on this naive appeal to authority as a sort of citation Bingo. Just waiting for Choi et al (2012) or “Harvard Study” to be thrown at us.


Repeated citing of flawed papers

Paul might consider that attitude harsh – but let’s take one paper he cites in his list of 30 – Cheng et al (2007). He referred to this paper also in his first article arguing that Cheng et al’s figure (on the left hand below) shows fluoridation ineffective. I pointed out his conclusion was unwarranted because of the weakness of the data and influence of confounding effects in inter-country comparisons. I illustrated this by showing  that the data for Ireland could be separated into fluoridated and unfluoridated components (see right hand figure). And this comparison within one country (with fewer confounding effects) illustrates that fluoridation was effective.

combined-who-irelandThe dotted line in the RH figure is effectively what Cheng et al (2007) used for Ireland in the LH figure.

Paul brushed off my response by saying “I would not exclude the researchers’ bias influencing this result!”  And he continues to use the same citation. I am sure he will continue to do so in the future despite the criticisms – because he is using these citations like a drunk uses a lamppost – more for support than illumination. He is approaching the literature with a fixed conclusion – searching for citations he can use to support those conclusions, and not basing his conclusions on an objective assessment of the literature.

Selective quoting

And taking just one of the unsupported claims Paul made in his Gish gallop:

“modern studies have not found tooth decay when fluoridation has been stopped in various communities.”

He includes Cuba and is obviously referring to the paper of Künzel & Fischer (2000) – Caries Prevalence after Cessation of Water Fluoridation in La Salud, Cuba. Yes this study found no increase in caries after stopping fluoridation and suggested why:

“A possible explanation for this unexpected finding and for the good oral health status of the children in La Salud is the effect of the school mouthrinsing programme, which has involved fortnightly mouthrinses with 0.2% NaF solutions (i.e. 15 times/year) since 1990.”

Similarly he includes east Germany. Künzel et al (200) – Decline of caries prevalence after the cessation of water fluoridation in the former East Germany – found no increase of caries in two German cities after fluoridation of water was stopped. But again the authors suggest why:

“The causes for the changed caries trend were seen on the one hand in improvements in attitudes towards oral health behaviour and, on the other hand, to the broader availability and application of preventive measures (F-salt, F-toothpastes, fissure sealants etc.).”

This is the thing about Gish Galloping – it avoids the horrible reality of context and details which often make the claims false. And Gish galloping by citation war is just another way of avoiding context and details but adding a layer of the fallacy of appeal to authority.

On the one hand the offender can pretend extensive knowledge and a damning case (even if one or more of there charges are refuted) – on the other hand his discussion partner can be presented as ignorant and without a case when they don’t reply to every single charge in detail.

The IQ gambit

Paul keeps returning to this question. It is obviously central to the message Fluoride Alert promotes and it does seem to catch the imagination of at least some people. How many times have I seen this sort of bald statement on Twitter?

alt_medicine.txt (@altmed_txt)
4/12/13 3:51 pm Fluoride acts to calsafiy peniel gland in your brain. That is why HITLER used it in Death Camps. It dumbs you down & makes you complacent.

 How often do we have the “Harvard study” thrown at us as final proof that fluoridation lowers IQ?

While getting a boost from the paper of Choi et al (2012) this is an old myth promoted by extreme anti-communist groups like the John Birch Society – the myth also included Stalin’s prison camps. I have always thought this claim weird as elemental lead in the form of bullets is usually a very effective form of control in such prison camps – surely putting fluoride in the water is not as effective?

But conspiracy theorists are not going to give this myth away so easily. It provides handy support for their claims that governments, under direction from the United Nations and as part of Agenda 21, fluoridate our water to produce a population of “sheeples” who won’t revolt! Or that it is some form of population control – even a way of killing off old people!

It is ironic that anti-fluoridation activists will on the one hand stress the observation from the York Review team that much of the research in this area is of poor quality – and then work hard to drag up any poor quality research they can find to support the claim of an effect on IQ!

Connett’s pre-occupation with this IQ gambit does raise some questions in my mind. I know he does not wish to be put on the spot for every infraction of his fellow activists. But it would be helpful for him to clarify his own position.

  • Does Paul believe in, or support the promotion of, the myth that Hitler and Stalin used fluoride addition to drinking water as a way of maintaining order in prison camps?
  • Does Paul believe that the US and some other governments use fluoridation to keep their citizens apathetic? If not is he prepared to criticise his supporter who do, like Anna Goodwin a local FANNZ activist?
  • Does Paul agree with his fellow activist who believe that fluoridation is used as a form of population control?

Mechanisms of beneficial action of fluoride.

Misinformation about the mechanisms for any beneficial action of fluoride on oral health is, like the IQ story,  central to the political message of anti-fluoridation groups here days. They have seized on improved knowledge about these mechanisms to promote a false scenario. In this they have achieved a certain amount of success. The Hamilton City Council bureaucrats, for example, still promote the message that fluoride water has no beneficial role because fluoride works by topical action (see Fluoridation Referendum Results prepared for the recent council meeting).

So I am not surprised that Paul persists in denial of the real scientific knowledge about these mechanisms. I will just summarise the misinformation he is promoting.

1: He continues to avoid the issue of a systemic role for fluoride. He says that my “stating over and over again that the fluoride ion is a natural constituent of apatites doesn’t get us very far.” Clearly he does not want to go in that direction.

The natural  scientific concentration on the surface mechanism operating to reduce mineralisation and enhance remineralisation as the major effect in limiting caries in existing teeth does help him a bit. But only by omission and turning a blind eye to the studies showing a systemic role with pre-erupted teeth. Papers like Singh and Spencer (2004). Relative effects of pre- and post-eruption water fluoride on caries experience by surface type of permanent first molars and Singh et al (2007). Effects of Water Fluoride Exposure at Crown Completion and Maturation on Caries of Permanent First Molars. And dare I repeat Newbrun (2004), Systemic Benefits of Fluoride and Fluoridation – a reference he has already ignored.

2: Labelling the scientifically accepted mechanism for the surface reaction with existing teeth as “Ken’s topical mechanism via saliva and plaque” is a really desperate shot. As is talk of “scarce data” because I cited only 4 papers! It is obviously not “my ” mechanism but the currently accepted mechanism for the major effects with existing teeth. One could cite expert after expert – none with my name.

However, he has at least tried to deal with the details in some of the papers I cited – far more consideration than he gives to the systemic role of fluoride. But of course he has a preconceived aim of finding any detail which he can use to discredited this currently well accepted mechanism. He relies on claiming that fluoride concentrations derived from drinking fluoridated water in saliva and plaque are insufficient for the mechanism. That they are below a specified required concentration (he has even pulled a value out of the literature from Featherstone 1999).  He concedes that maybe these concentrations do spike at a sufficiently high concentration but decline too rapidly to have an effect.

Let’s consider these points:

3: Paul has seized on a value of 30 ppb F in saliva as a minimum concentration for the surface mechanism. I don’t think that is universally agreed – which is hardly surprising because of the complex chemistry involved. The surface reaction is dependent on the concentration of Ca2+, orthophosphate, F and not well-defined organic species. It is markedly dependent on pH and the carbonate content of the surface layers of the bioapatite.

The interaction of fluoride with the tooth surface is also a dynamic process. The pH changes relatively quickly, dropping with bacterial action on carbohydrates and then increasing – this influences the surface reactions.


Image credit: SAMPLE #36 WRITING TASK

Mineralisation and remineralisation of surface layers of the teeth is a process see sawing throughout the day


Image credit: Buzalaf (2011), Fluoride and the Oral Environment, Monographs in oral science ; v. 22. 

Fluoride in saliva and biofilms on the surface reduces the mineralisation process and enhances the remineralisation process. In simple terms we can understand that as influencing the pH values these process occur at.


Image credit: Fluoride as a protective factor for tooth decay.


Image credit: Buzalaf (2011), Fluoride and the Oral Environment, Monographs in oral science ; v. 22. 

Yes, fluoride concentrations in saliva and plaque do reach a maximum after drinking water and eating food containing fluoride, as well as after brushing teeth with fluoride containing toothpaste. These concentrations then decline over the next few hours. DenBenstein (1997) found salivary fluoride concentrations declined to baseline values 45 minutes after brushing children’s teeth. Naumova (2012) showed a similar decline but the figure from her paper illustrates another feature – the high varibaility of the concentrations.


Image credit: Naumova (2012)

However, concentrations in plaque, surface biofilms, decline less rapidly. Naumova (2012) reported elevated plaque fluoride concentrations for 2 hours, decreasing to baseline concentrations in 6 hours.  Petersson et al (2002) also found storage of fluoride in plaque for several hours.

4: So fluoride concentrations in saliva after drinking water or eating food containing fluoride can be quite variable. They also decline over time, but the plaque has a storage effect (Petersson et al 2002). So the beneficial activity of fluoride via a surface reaction on teeth requires relatively frequent fluoride inputs. Fluoridated water provides this. In effect it supplements fluoride inputs via tooth brushing because the latter is far less frequent. In fact Whitford (2002) say:

“Based on these findings and reports in the literature it is concluded that, for persons whose drinking water is fluoridated, plaque [F] throughout much of the day is not significantly increased by the use of a fluoridated dentifrice. Instead they are directly related to plaque [Ca]. These findings offer at least a partial explanation for why fluoridated dentifrices and drinking water have similar cariostatic effects.”

5: ten Cate (1982)  reports that susceptibility to mineralisation also declines over time because of the cycling mineralisation-remineralisation procedure. Presumably this is a result of improvement in the chemical composition of surface layers – incorporation of fluoride and removal of carbonate.

So, I wouldn’t be putting my money on a single value for the minimum effective value of salivary fluoride concentration required for this surface effect. And I can understand why some workers insist that even the low salivary fluoride concentration resulting from ingested fluoride could still play a role.


In this article I have dealt in a bit more detail with the ethical questions around the fluoridation issue and the surface mechanisms proving a defence against tooth decay with existing teeth. Depite this, some readers might feel I have spent more of this article attacking Paul Connett’s debating methods, and not dealing with the science. My justification for this is the tactics Paul used in his last article, relying on a Gish galloping presentation of a long list of arguments and the fallacy of authority by quoting, without amplification, a long list of citations. This has been combined with the fallacy of demanding proofs of negatives commonly used by science deniers in the creationism-evolution debate.

I think it is necessary to bring these tactics to reader’s attention.

Anyone wanting to follow the debate and/or check back over previous articles in the debate can find the list of articles at Fluoride Debate.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page

Fluoridation debate: Why I support fluoridation – 2nd reply to Connett

This is Ken Perrott’s response to Paul Connett’s second criticism of Ken’s article Fluoride Debate: Why I support fluoridation – 2nd response from Connett.

For Ken Perrott’s original article see – Fluoride debate: Why I support fluoridation.

It is a pity that Paul Connett chose to ignore the ethical question of balancing personal choice and social good because he took my comments on this as a personal criticism of him. They were not meant to be. I am happy to discuss the science but, in the end, science cannot make ethical and values decisions for us. Yes, it can, and should, inform those decisions – but pretending they are only about science does a disservice to science and to ethics.

Unfortunately science is often used in these sort of debates as a proxy for values issues. Professor Gluckman pointed that out in his statement What is in the water?  An excellent article by Tania Ritchie in Science and Society outlines the dangers of this approach (see  The fluoridation debate: why we all lose when we pretend it’s just about science). She shows how using science as a proxy backs people into pseudoscientific corners (and that is certainly an issue for these opposing fluoridation). It also places an impossible demand of certainty on science (“prove to me beyond doubt that fluoride at optimal concentrations is completely safe – if in doubt leave it out”). And concentration on the science often disguises poor ethical positions. She concludes:

“Using good science to counter bad science is productive. Using good science to tell us what will happen if we make a certain decision is also, of course, vital. But pretending science can tell us what decision we should make, or trying to counter ethical concerns with science, will never be helpful.”

Well, for the moment I guess I am opting for “using good science to counter bad science” but I hope we can return to these ethical issues at some stage.

Nature of bioapatites and systemic role for fluoride

Paul seems not to have taken on board my description of the structural role of fluoride in apatites and the recognised beneficial role of ingested fluoride. (Perhaps he considered that section was somehow a personal criticism and should be ignored.)

Mind you, I keep coming across that problem with other anti-fluoride  activists. They wish to talk only about topical application of fluoride, and ignore completely the beneficial effects of ingested fluoride. This seems to create reading, hearing and comprehension problems for them. So I get accused of advocating that suntan lotion should be drunk or similar attempts at humour!

However, it is a critical feature of this debate so I will just start this response by briefly repeating a few things.

  • Fluoride is a normal, natural component of bioapatites. In the real world these don’t exist as end-member compounds such as hydroxylapatite or fluoroapatite. They are more correctly described as hydroxyl-fluoro-carbonate-apatites.
  • Accumulation of fluoride, together with calcium and phosphate, in our bioapatites is a normal part of development. This is beneficial because it helps strength our bones and teeth, and lowers their solubility.
  • Both insufficient fluoride, or excess fluoride in our bioapatites can cause problems.
  • Excessive dietary intake can result in excessive fluoride in our bones and teeth. Insufficient intake may also cause our bioapatites to be weaker and more prone to dissolve. When dietary intake of fluoride is reduced fluoride can be lost from bones and calcified tissues.
  • The scientific literature reports that fluoride has a systemic role benefitting bones and pre-erupted teeth

Surface mechanisms for reducing tooth decay

We seem to be making a little progress here with the so-called “topical” mechanism – but only a little and very grudgingly. Paul has apologised for misrepresenting my explanation of the surface mechanism for the action of fluoridated water in countering tooth decay in existing teeth. He acknowledges that I was discussing the transfer of fluoride to saliva from water during drinking water, and not the smaller concentrations coming from the salivary glands after ingestion.

In this I was simply reporting what I have read in the scientific literature.  But Paul will still have none of that. He concedes that fluoride in saliva “may or may not do something” and presents his own “simple personal observations” to claim that there is little chance of drinking water mixing with saliva. Not the first time I have heard this argument – and it always brings a picture to mind of a committed anti-fluoride activist drinking their water through a tube down the throat. I leave it to readers to observe their own drinking behaviour and decide if drinking water has little chance of mixing with saliva – or transferring ions to saliva.

So it is one step forward and another step back. Made worse by his assertion (from personal experience) “that the fluoride ions have little opportunity to form a biofilm on any teeth other than the back of the front teeth.” Of course the fluoride does not form a biofilm. It and other ions in the water and saliva do, however, transfer to, and diffuse through, existing biofilms (plaque) on the teeth.

There are quite a few reports of the effect of regular consumption of fluoridated water increasing the F concentrations in saliva and plaque both after ingestion (eg Cury & Tenuta 2008Martínez-Mier 2012) and directly Featherston 2000Bruun & Thylstrup 1984). (Yes, I realise that the CDC sates that the ingested fluoride delivered to saliva “is not likely to affect cariogenic activity” and this is echoed by other writers. However, there still seem to be workers who argue this does contribute and I am aware of laboratory experiments showing the mechanism can work at very low fluoride concentrations. But this is a detail I will leave to the experts – it doesn’t affect the current exchange).

Loaded language and scientific knowledge

Paul again refers to advances of scientific knowledge in a sneering way. He claims that the CDC “admitted” that research indicated the prevention of dental caries by fluoride occurs by a topical mechanism in existing teeth. He also speculates that the CDC “was scrambling to salvage some kind of role for fluoridated water . . . Despite its admission of the predominance of the topical effect.” Can somebody with research experience in chemistry really see scientific progress as some sort of winning-out over a conspiracy to ignore the “truth?”

Mary Byrne, a local anti-fluoridation spokesperson, shows a similar apparent misunderstanding of the nature of scientific knowledge when she describes, disparagingly,  this progress in understanding as scientists being “wrong for fifty years.” She keeps repeating this even though her error has been explained to her.

These characterisations are like saying Newton was wrong with his laws of motion or that he was somehow hiding the truth and Einsteinian relativity  is simply a case of scientists being forced to “admit”, or “concede” they were wrong – as if they had hidden something!

Use of loaded language like this has a political purpose which interferes with proper understanding of the science.

The journal Fluoride

Paul describes my comments about the journal Fluoride, and its editors, as “derogatory,” and accuses me of “double standards.” I think that shows a sensitivity and inability to consider my comments objectively. Not surprising, as Paul has some “irons in the fire” on this issue.

I said that “if I had some credible findings in fluoride chemistry and wished to present a paper to the scientific community for their consideration Fluoride is the last journal I would choose.” This isn’t completely hypothetical because I have published a few papers on fluoride chemistry. So how do I decide where to publish my work?

Firstly, my fluoride work was relevant to pedology and soil chemistry so it was natural to consider soil science journals. This was the audience to aim for and our work was of direct relevance to readers of those journals. I doubt that many of our intended audience or their institutes subscribed to, or read, Fluoride.

But, today if I were considering a general  journal and had a look at Fluoride what would I find. First of all the website (where I would go to judge the journal’s scope, requirements and refereeing policy) – seriously, does this show a credible scientific society or editorial office?


This is what greets you as the home page for the Fluoride journal (http://www.fluorideresearch.org/)

That extremely amateurish web page puts me off – perhaps there are other general journals dealing with fluoride (contrary to Paul’s claim). Let us see if Journal of Fluoride Chemistry is better? See the difference?


Home page for the Journal of Fluorine Chemistry

Secondly, a quick skim of accepted papers in Fluoride indicates many are related to areas where fluoride toxicity is a problem because natural levels are high or excessive. The quality of many of these papers appears poor, a common problem where there are many authors whose main language is not English. It has a predominantly “third World” appearance. This would also raise a flag about possibly low standards of editorial review. Have a look at the list of contents for one of the 2007 issues.

None of these factors would attract me as a working and publishing scientist concerned at establishing a publication record in high quality and credible journals.

However, if I was a non-English speaker with routine work which I might find difficulty publishing elsewhere, and especially if that work was related to areas where natural fluoride levels were high, I would probably consider the journal. With the realisation in the back of my mind that I would probably have no luck with submission to a more reputable journal.

Now, I am not being “personal” or “derogatory” in making  that realistic evaluation. Nor do I think there are “double standards’ in choosing a good journal for publication. Good work deserves a good journal for publication.

Paul effectively concedes this in referring to attempts by Xiang et al to get their work published in a more reputable journal. He laments the fact that this journal would not include material already published in Fluoride (standard procedure in the publishing world) as amounting to Xiang’s material being “withheld from the mainstream scientific community.” (Paul obviously agrees that Fluoride does not have a good standing in the mainstream scientific community). The lesson being that Xiang should have gone for the reputable journal first time around. Why publish in a journal which does not give access to “the mainstream scientific community” if one’s work is good enough to get published in a reputable journal

That is a sensible question – not a derogatory one.

Connett’s relation with Fluoride

It is instructive to look at Paul Connett’s own publications in Fluoride. He claims to have researched the issue for 17 years and I would expect that at least some of his research papers would have ended up in this journal.

A simple search for the name Connett showed me a couple of guest editorials – often coauthored with editors of the journal (see for example Professionals moblize to end water fluroidation and Misplaced trust in official reports), a book review (coauthored with editors of the journal), reports of the International Fluoride Society (IFS – owner of Fluoride) conferences. There were abstracts of papers or posters presented at IFS conferences authored by Paul, Ellen and Michael Connett – but no sign of formal papers for these. (I hope Paul will correct me and provide links if I have missed papers with full text.)

This at least tells me that Paul is on excellent terms with those editing and running this journal. Not surprising when one looks at the names in the editorial board of the journal, the western contributors to the journal and the names on the advisory board of Paul’s activist organisation Fluoride Alert.

Another thing that stands out for me about the editorial and advisory boards is the large number of retired, former, emeritus academics (around 17 from a glance). In the past I have also noticed this about the organisations and petitions of climate change climate contrarians/deniers/pseudosceptics. As a retired scientist myself I can appreciate how such issues can become hobbies, and avenues for social involvement and personal standing for people who formerly relied on their employment and professional standing for such things. I can also appreciate that retirement often also means loss of contact with current research and findings. This increases my suspicions of the journal and organisation.

There was one normal looking journal paper by Michael Connett Vulvar paget’s disease: recovery wihtout surgery following change to very low-fluoride spring and well water.” My impression is this was simply an anecdotal history for one person – probably not normally acceptable in a scientific journal (unless at least written by the practicing medical person handling the case). A quick search of Google Scholar shows this to be Michael’s sole scientific paper – perhaps not surprising as he is not a scientist. He is the Special Projects Director for the Fluoride action network, an attorney in Philadelphia, PA, and received his law degree from Temple Law School in 2011. But now has a scientific publication record!

(Note for non-scientists wishing to show a scientific publication record. There  are plenty of anecdotal stories on the internet by people claiming sensitivity to fluoride. Hell, the other day I read the personal account of one person with skeletal fluorosis which cleared up immediately he stopped drinking tap water! You could select your own “case history,” write it up as a scientific paper and submit to Fluoride. Mind you, your paper might not be all that visible to the “mainstream scientific community”).

Looking at Fluoride, Fluoride Alert and the International Society for Fluoride Research I get a strong impression of a group who take in each other’s laundry – but at the same time give publication space for some third world scientists who may not meet the standards of more reputable journals.

Paul gave it away when he reported to us that “the US National Institute of Health (NIH) has refused to cover the contents of this journal in PubMed.” Surely that tells us something about how this journal is considered by the science community (and please – if one has to resort to conspiracy theories to explain this the argument is surely already lost.)

Bones, hip fractures and the literature

Kurt Ferre’s comment about misrepresentation of the Li et al (2001) paper referred to Paul’s note on it in Fluoride Alert (Reason 29 of 50 reasons to oppose fluoridation). Here Paul did describe the data as relating to hip fractures and not over all fractures. OK, Paul in chapter 17 of his book may have been more specific but that is not what Kurt referred to. (By the way, I am still plodding through Paul’s book – on chapter 9 at the moment).

Paul claims I “prefer” an “interpretation” of the Li et al (2001) paper that there is a “sudden” appearance of hip fracture at a higher concentration rather than a linear increase from low concentrations. He is wrong – I don’t prefer any specific interpretation. I was merely pointing out what can be drawn from the statistical analysis of the data.

One of our commenters has already noted that Paul’s argument for his own intepretation of the data here amounts to special pleading – where he has to ignore, or denigrate, the statistical analysis. He is pleading when he writes that increases “appear to be ‘real’ even though they are not statistically signficant individually.” Or that the data “appear consistent with a linear regression. Statistical significance is not the final word on whether a data point or data set is real or not.”

These were the sort of statements I would put red lines through when I was reviewing papers submitted for publication.

However, this is a digression. The interpretation of the increase at higher concentrations is not important. The fact is neither overall fractures or hip fractures showed an increase at fluoride concentrations considered optimum for oral health.

It was clear to me when I originally read and wrote about  Li et al’s (2001)  paper (see  – Is fluoride an essential dietary mineral? ) that the increased incidence of overall fractures at concentrations below optimum did not refer to hip fractures. The authors specifically brought that to readers attention – “the data show a somewhat different pattern for hip fractures in relation to the water fluoride levels. . . Instead, the prevalence of hip fractures was stable until the water concentration reached 1.45–2.19 ppm.” They qualified this with “However, it may not be appropriate to conclude that the risk of hip fracture is more sensitive to the water fluoride concentration as compared with overall fractures, because the number of hip fractures in the present study is relatively small.” And they did conclude that “our results on hip fractures support previous findings that fluoride around 1 ppm in drinking water does not increase the risk of hipfracture.”

This diagram by Ethan Seigel (which I reproduced in an article earlier this year (see Getting a grip on the science behind claims about fluoridation) was clearly taking on board Li et al’s work – when perhaps it should not have been so specific.

But of course the issue of hip fractures does not rest with the work of Li et al alone. I wrote about this specifically in Fluoridation: the hip fracture deception  where I also mentioned the recent paper of Näsman et al (2013) “Estimated Drinking Water Fluoride Exposure and Risk of Hip Fracture: A Cohort Study showing no significant correlation of hip fractures with fluoride in drinking water at the optimum concentrations.


Delivery systems: It seems I must respond to Paul’s suggestion of “an alternative delivery system for fluoridated water” – selling fluoridated bottled water. I guess that already happens in many places but I did not take his suggestion  seriously because he is offering it as a substitute for already existing social health policies. That is not my area of expertise but I can understand how fluoridated water and fluoridated salt are effective as social policies for overcoming problems where the natural fluoride levels are deficient. Surely bottled water in the corner of a “supermarket, pharmacy or clinic” hardly measures up as a social health policy? Fluoridated salt seems to me to be a more credible alternative to water fluoridation.

Having said that, bottled water is culturally preferred in some countries and is attractive to some age groups in others. There are suggestions, therefore, that fluoridation of bottled water should be encouraged. New Zealand and Australia recently brought in regulations allowing this.

Inference from high concentrations: Paul has objected to my criticism that he often relies on extrapolation from laboratory or epidemiological  studies where higher than optimum fluoride concentrations were used.  He responded by discussing Xiang et al (2003) and argued that some of  the studies covered by Choi et al  (2012) did include lower concentrations.

However, there is still a tendency to then fall back on all the studies to give extra weight to his assertions, rather than just rely on the low concentration studies. I think the image below prepared by fellow New Zealander Andrew Sparrow helps put this issue into context. High fluoride cases in Choi et al (2012) were almost all completely out of the zone for optimum fluoridation of drinking water.

Chinese IQ

Appeal to authority with declarations: This tactic is used a lot by anti-fluoride activists. The poster below is a recent example from Fluoride Free NZ. The inclusion of a citation gives it some authority – but can anyone find that paper? No one at Fluoride free could – yet they were promoting a claim using the citation!

The Journal of Dental Medicine is now defunct and I could find no abstracts or full text on the internet. However, I did find a description at http://slweb.org – a well-known anti-fluoride activist site. This claimed adverse reactions, affecting “the dermatologic, gastro-intestinal and neurological systems,” to fluoride in 1% of the group studied!  I would have liked to check out the statistical analysis used in the study as this seems a very small response. Was 1% significantly different to zero in this study?

What the hell – Fluoride Free NZ doesn’t care. They went ahead with a poster and its promotion anyway. As a political activist group they are concerned more with moulding public opinion than the facts.

Paul might argue this case is a diversion he is not responsible for. But my point is that activists do this sort of thing all the time. And Paul is no different with the way he quotes from the NRC (2006) report in his section “7. What other authorities are saying about fluoride as a neurotoxicant.”

He quotes phrases like:

  • “the results appears significant enough to warrant additional research on the effects of fluoride on intelligence.”
  • “These changes have a bearing on the possibility that fluorides act to increase the risk”
  • “More research is needed to clarify fluoride’s biochemical effects onthe brain.”
  • “studies of populations exposed to different concentrations of fluoride in drinking water should include “
  • “Studies of populations exposed to different concentrations of fluoride should be undertaken”
  • “Consideration should be given to assessing.”

The point is one can agree with all these suggestions for ongoing and future research and still accept the current assessment that fluoridation is safe. Just because there is a logical possibility of a suggested danger does not, in itself, make that danger real.

This ongoing research is happening and health authorities do monitor current research findings. In New Zealand the Ministry of Health set up  the National Fluoride Information Service to do this specific job and it regularly reports current research findings. Similarly, a report from the NZ Parliamentary health committee just the other day recommended:

“the Government work with the Ministry of Health to ensure that the addition of fluoride to the drinking water supply is backed by strong scientific evidence and that ongoing monitoring of the scientific evidence is undertaken by, or for, the Ministry of Health, and that the Director-General of Health is required to report periodically to the Minister of Health on the status of the evidence and coverage of community water fluoridation.” (see From dental neglect to child abuse?).

It is irresponsible to use such urgings to continue research as some sort of proof that there are problems sufficiently big enough to warrant abandoning a social health policy known to help people. Or to call that social health policy “reckless,” as Paul does.

Paul Connett does the same thing with the paper by Xiang et al (2003) and other Chinese work in the area of IQ. He acknowledges himself that “there are weaknesses in many of these IQ studies.” These weakness and the speculative nature of his conclusions do not stop him from seriously claiming that there is a very low limit of sensitivity to fluoride effects on IQ. I repeat my question from my last article about the huge variability in the data and how the hell one can place any confidence on the result drawn from Xiang’s figure.

“Yet Paul uses Xiang’s paper to authoritatively claim it had “found a threshold at 1.9 ppm for this effect.” (What effect he refers to is unclear.) How reliable is that figure of 1.9 ppm (actually 1.85 or 2.32 ppm F in the paper) –  considering the huge variation in the data points of the Figure 1? (Unfortunately the paper is not a lot of use in explaining that figure – reviewers should have paid more attention.)”

The final request: Paul wants me “to list the primary studies that you have read which most convinced you that fluoridation is both safe for the bottle-fed baby and for the adult over lifelong exposure.” In thinking about this I have concluded it is a strange request because I don’t think creative scientists think that mechanically.

My concepts and ideas derive from multiple sources – I never put my eggs all in one basket as it were. I can find I am impressed by something in a paper which also has something which doesn’t impress me. Consequently I take what I can from wherever I can and try to critically  understand what I read.

It’s a bit like that with people. You have to accept them warts and all and avoid the immaturity of placing anyone on a pedestal – a sure way to later find they have feet of clay.

So unfortunately I cannot satisfy Paul’s request. He will have to deal with the actual arguments I put forward.

As for the issue of bottle-fed babies – I am sure this will come up at some stage. It already has in the comments discussion.

Anyone wanting to follow the debate and/or check back over previous articles in the debate can find the list of articles at Fluoride Debate.

See also:

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