Tag Archives: debate

NZ Fluoridation review – Response to Micklen

I welcome open and transparent discussion here so am thankful to Dr Micklen for his response (see NZ Fluoridation review – HS Micklen responds to critique). Unfortunately he is the only author or “peer-reviewer” of Fluoride Free NZ’s report criticising the NZ Fluoridation review to accept my offer of a right of reply to my critiques. A pity, as if any of them think I have got things wrong, and they can support this with evidence, I certainly want to know about it. There are three aspects to Dr Micklen’s reply – dental fluorsis chronic kidney disease and his critique of my letter in the journal Neurotoxicology and Teratology –   Perrott (2015). I will deal with these separately.

Dental fluorosis

I appreciate Dr Micklen is unhappy about my criticisms of his article, and my suggestion his comments of dental fluorosis were muddled. I may have been a bit harsh but he has still not responded to my specific criticism that he:

“unfairly attributes the more severe forms [of dental fluorosis] to community water fluoridation (CWF). Consequently he calculates a cost of dental treatment which is wrong.”

The key problem is that Micklen is assuming that all the  medium and severe dental fluorosis can be attributed to CWF, whereas none of it can. Briefly reviewing the argument – the figure below is from the NZ Ministry of Health’s Our Oral Health – the same source Micklen used. My comment on the relevance of the different grades of dental fluorosis was:

“Moderate and severe grades of dental fluorosis are common in areas where fluorosis is endemic, but relatively rare where CWF is used. Occurrences in the latter case, despite the low concentrations of fluoride in treated drinking water, will have other causes – high natural levels in well water, industrial pollution, excessive consumption of toothpaste, etc.”

The important factor is that severe and moderate forms of dental fluorosis are not caused by CWF. CWF can contribute to mild and very mild forms of dental fluorosis but because these are usually judged positively they certainly don’t need expensive veneers – my dentist colleagues advise simple microabrasion usually works. So Micklen was wrong to suggest the cost of cost of veneers (up to $1750 per tooth) should be attributed to CWF because such costs would be encountered in non-fluoridated areas as well. (In fact, if Micklen had calculated costs for such treatment in non-fluoridated areas using the “Oral Health” data in the literal way he did for the fluoridated areas,  he would have found costs to be higher than in non-fluoridated areas! Certainly doesnt’ support his claim but a meaningless result because of the small numbers and large variability).

Chronic kidney disease

Micklen accuses me of  using “a piece of grammatical legerdemain to pretend that I [Micklen] called for CKD sufferers to be warned to avoid tap water, which I did not.” Granted he left himself a way out by actually writing:

“I suspect that most opponents of fluoridation would call for CKD sufferers to be warned to avoid tap water. Possibly the NZ health authorities have done so.”

OK, so its not a direct personal recommendation (perhaps he doesn’t belong to the group of “most opponents of fluoridation”) but a reader could be excused for getting that message and in this context it comes across as “dog whistling.” However I will accept his assurance now that:

” In fact, I am inclined to agree with him [me] that that might be extreme in the present state of knowledge.”

As for questions like: “Does further research on the topic receive any funding priority, for example?” – well this is a round about way of giving the message that it doesn’t. Perhaps he should actually check that out and give some evidence instead of making an unwarranted implication. This tactic of posing unfounded questions to convey an unwarranted message is typical of the approach Micklen and Connett take in their book The Case against Fluoride. I criticised this tactic in my exchange with Paul Connett (see Fluoride Debate). I reject Micklen’s suggestion that:

“Perhaps it would be embarrassing, too, for a government to insist on putting fluoride in the water and then advise a substantial number of people not to drink it – or so one might think.”

That is silly – it is like a conspiracy theory. Why would genuine health authorities refuse to give warnings to a small group of people who might be put at risk from a social health policy that is beneficial to the vast majority? Surely they are used to such situations. I also think he is waxing lyrical with the word “substantial!” The numbers involved would be very small, if any, and such a group would already be advised about a number of risks to them because of their condition and treatments. Micklen also lets his ideological position take over  by drawing the implication from my article that I am saying CWF is “effective and safe – for some.” Far from it. Surely I am saying it is effective and safe for the vast majority (which is what we can expect from a social health policy) and simply recommending (as in all such policies) that the small group of people, if any, who might be at risk should use alternatives. I am actually saying that CWF is effective and safe for at least  the vast majority and that claims to the contrary should be backed up with evidence which should be considered critically

Severe dental fluorosis and cognitive deficits

I thank Dr Micklen for his comments on my letter in the journal Neurotoxicology and Teratology – (Perrott 2015). I am pleased he accepts the hypothesis that severe dental fluorosis could explain observations of cognitive deficits is worth considering and  he agreed with the other reviewers the letter was worth publishing. Influence of age I take his point that the poor appearance of teeth may not influence young children (ages 6-8 as in the small the group Choi et al, (2015) studied). However, this is pure speculation on his part and is surely a detail. A detail that should be considered in any planned research incorporating this hypothesis, but not in itself a reason for rejecting the hypothesis out of hand – surely? Unless, of course, he can give evidence to support his suggestion. I notice that he does not support the idea with any citations so suspect the idea is more one of straw-clutching  than a serious suggestion. Actually most, but not all, of the citation I used did indeed refer to work with older children. Some were review papers and did not limit their review to any age group. Aguilar-Díaz, et al., (2011) considered children from 8 – 10 years old, Do and Spencer, (2007) studied 8-12 year olds and Abanto et al., (2012) 6-14 year old children. Chikte (2001) studied three groups: 6, 12, 15 year olds. However, I found a quick literature search showed reports of negative effects of oral defects like tooth decay on the child’s quality of life. Kramer et al., (2013) reported this for ages 2 – 5, Scarpelli et al., (2013) for 5 year olds and Cunnion et al., (2010) for 2 – 8 year olds. So, I suggest on the available evidence the negative influence of severe dental fluorosis on quality of life (and possibly cognitive deficits) is likely to occur even in younger children who have not “reached an age to be self-conscious about their appearance.” I don’t think young children are as immune to social attitudes and personal appearance as Dr Micklen suggests. Does effect depend on how common dental fluorosis is?  Dr Micklen suggests that:

“Since fluorosis was common in the community [the children studied by Choi el., 2015], having the condition would not appear abnormal.”

Again I think he is indulging in straw-clutching, or special pleading. special-pleading-fallacy Clearly medium and severe dental fluorosis is far more common in this Chinese group than in countries like New Zealand which use CWF. In the graph below I compare their data with that for New Zealand and USA. Incidentally, this figure shows why the data from Choi et al., (2012, 2015) should not be used as an argument against CWF – yet that is what Micklen did in his original article. DF---good-and-bad But this does not mean that those children with more severe forms will not stand out against the children with less severe forms. There is always a range of appearances of such defects in a group of children. Some will obviously suffer more than others because of their appearance. If Choi et al., do continue to include detailed analysis of dental fluorosis in their future work on this issue then it will be possible to compare cognitive deficit measurements with dental fluorosis indices in a larger group. Such data will be interesting. However, discussion of details like this is premature. My letter simply raised to idea as an alternative worth considering and encouraged the group to continue including detailed dental fluorosis measurements in future work. I was also concerned that they were not being sufficiently open-minded in their choice of a working hypothesis. I concluded my letter with:

Researchers need to be careful not to limit their possible hypotheses or research approaches. Unfortunately Choi et al. (2014) appear to be doing just this with their plans for a larger scale study targeted only at “fluoride’s developmental neurotoxicity.”

Unfortunately none of this group have yet responded to my letter. So, again, I thank Dr Micklen for his feedback on that letter – and his acceptance of the right-of-reply to my article critiquing the FFNZ report. See also:


Abanto, J., Carvalho, T. S., Bönecker, M., Ortega, A. O., Ciamponi, A. L., & Raggio, D. P. (2012). Parental reports of the oral health-related quality of life of children with cerebral palsy. BMC Oral Health, 12, 15. doi:10.1186/1472-6831-12-15 Aguilar-Díaz, F. C., Irigoyen-Camacho, M. E., & Borges-Yáñez, S. A. (2011). Oral-health-related quality of life in schoolchildren in an endemic fluorosis area of Mexico. Quality of Life Research : An International Journal of Quality of Life Aspects of Treatment, Care and Rehabilitation, 20(10), 1699–706. Chikte, U. M., Louw, A. J., & Stander, I. (2001). Perceptions of fluorosis in northern Cape communities. SADJ : Journal of the South African Dental Association = Tydskrif van Die Suid-Afrikaanse Tandheelkundige Vereniging, 56(11), 528–32. 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. Choi, A. L., Zhang, Y., Sun, G., Bellinger, D., Wang, K., Yang, X. J., … Grandjean, P. (2015). Association of lifetime exposure to fluoride and cognitive functions in Chinese children: A pilot study. Neurotoxicology and Teratology, 47, 96–101. Cunnion, D. T., Spiro, A., Jones, J. a, Rich, S. E., Papageorgiou, C. P., Tate, A., … Garcia, R. I. (2010). Pediatric oral health-related quality of life improvement after treatment of early childhood caries: a prospective multisite study. Journal of Dentistry for Children, 77, 4–11. Do, L. G., & Spencer, A. (2007). Oral Health-Related Quality of Life of Children by Dental Caries and Fluorosis Experience. Journal of Public Health Dentistry, 67(3), 132–139. Kramer, P. F., Feldens, C. A., Ferreira, S. H., Bervian, J., Rodrigues, P. H., & Peres, M. A. (2013). Exploring the impact of oral diseases and disorders on quality of life of preschool children. Community Dentistry and Oral Epidemiology, 41(4), 327–35. NZ Ministry of Health. (2010). Our Oral Health Key findings of the 2009 New Zealand Oral Health Survey. Perrott, K. W. (2015). Severe dental fluorosis and cognitive deficits. Neurotoxicology and Teratology. Scarpelli, A. C., Paiva, S. M., Viegas, C. M., Carvalho, A. C., Ferreira, F. M., & Pordeus, I. A. (2013). Oral health-related quality of life among Brazilian preschool children. Community Dentistry and Oral Epidemiology, 41(4), 336–44.

NZ Fluoridation review – HS Micklen responds to critique

I have posted several articles in a series critiquing contributions to the Fluoride Free NZ report Scientific and Critical Analysis of the 2014 New Zealand Fluoridation Report which is aimed at discrediting the recent review Health Effects of Water Fluoridation: a Review of the Scientific Evidence produced by the Royal Society of NZ together with the Office of the Prime Minister’s Chief Science Advisor. The articles in this series are collected into a pdf document which can be downloads from Download report analysing anti-fluoride attacks on NZ Fluoridation Review.

In an attempt to encourage a discussion on the fluoridation review and the FFNZ report I offered all the authors and “peer-reviewers” of the FFNZ report the right of reply to my critiques. So far Dr H. S. Micklen (whose article I critiqued in Fluoride Free NZ report disingenuous – conclusion), is the only one to take up this offer.

Here is his reply. 

I thank Dr Perrott for reproducing my notes on the NZ Fluoridation Review and appreciate his comments. My appreciation would be warmer had he spent less time using his imagination and paid more attention to what I actually wrote.  He has me bustling around, agenda in hand, clutching at straws here, raising bogeys there, scaremongering, relying on this, calling for that, and getting confused about different grades of fluorosis (as if..,). All nonsense.  If I “distort the science” as Perrott’s headline proclaims, he does a great job of distorting the distortion.

Most of my short piece merely commented on a few places where, in my opinion, the NZ report failed – through error, omission or incompetence – to reach proper standards of objectivity and impartiality and exhibited ill-founded complacency. Since the NZ report was highly biased in favour of fluoridation, any criticisms of it are likely to have an anti-F flavour. Too bad; I was dealing with the report’s view of the science, not pushing my own. I avoided speculating on the outcome of issues that I consider unresolved, dental fluorosis (where Perrott makes nonsense of what I wrote) being the only exception.

Most of these issues have been argued over ad nauseam and I shall not try to unscramble Perrott’s lucubrations. The question of chronic kidney disease and its possible cardiovascular consequences is perhaps an exception. I gave credit to the Review for discussing the paper by Martin-Pardillos. Agreeing with the Review’s opinion that the results needed to be confirmed, I remarked “The interesting question is, what should happen meanwhile?” That is not a rhetorical question. What does, or should, happen when an alarm bell sounds over a long-established procedure? Does further research on the topic receive any funding priority, for example?  Perrott uses a piece of grammatical legerdemain to pretend that I called for CKD sufferers to be warned to avoid tap water, which I did not. In fact, I am inclined to agree with him that that might be extreme in the present state of knowledge. Perhaps it would be embarrassing, too, for a government to insist on putting fluoride in the water and then advise a substantial number of people not to drink it – or so one might think. But Perrott concludes “Any patients who are particularly worried can then take steps like using filtered water for their own peace of mind. This seems more appropriate than denying the rest of the population access to a simple, effective and safe (for them at least) social health policy like CWF.”  So that’s all right then, thanks to the patients, whom Perrott doubtless consulted, being willing to promote the alleged greater good. He has pricked a hole in the old mantra, though: “effective and safe – for some”.

Perrott asked for my feedback on his idea about the possible effect of dental fluorosis on IQ.  Since then his paper has appeared online as a short article in Neurotoxicology and Teratology. Perhaps the best thing I can do at this stage is pretend that it had arrived on my desk for peer review. I would have commented as follows.

“This communication refers to a recent paper by Choi et al (2014) that reports certain cognitive defects in young children affected by moderate-severe dental fluorosis. Choi et al suggest that this is due to an adverse effect of fluoride on the developing brain. The present author proposes an alternative explanation, namely that fluorosis itself, and the stress of living with it, can affect learning and general quality of life and result in poor performance in certain types of cognitive test. This appears to be a novel idea and, as such, is suitable in principle for publication as a short communication. There is, however, a fundamental question that the author should be invited to address and clarify with a view to possible resubmission.

“The paper is somewhat discursive and lacking in focus and in the course of it the author seems to lose track of what age group he is talking about. Surprisingly, he does not mention the age of Choi’s (2014) subjects, which averaged 7 years  (range 6-8). When he finally presents evidence that moderate-severe fluorosis is aesthetically displeasing and likely to impair quality of life, all of it relates to older children, mainly teenagers, who have reached an age to be self-conscious about their appearance and have been living with fluorosis for several years. In contrast, 16% of Choi’s (2014) subjects had no erupted permanent teeth at all and in the remainder eruption of the first permanent teeth would have been very recent. Since fluorosis was common in the community, having the condition would not appear abnormal. The crucial question is whether the author is proposing that the quality of life of these young children is so compromised by fluorosis as to impair their performance in cognitive tests. Apparently the answer is a tentative affirmative: It is just possible that the negative quality of life associated with oral defects like severe dental fluorosis contribute to cognitive deficits reported by Choi et al. (2012, 2014)’

“The author needs to discuss this issue in a transparent fashion so that readers can judge for themselves whether the proposal is plausible. Conversely, if he is not making such a proposal, that too should be made clear.

“The author might wish to refresh his memory of the paper by Hilsheimer and Kurko (1979), which really is of virtually no relevance to his argument.”

I hope this helps.

H S M 12 February 2015

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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.

Hodge, HC (1963). “Safety Factors in Water Fluoridation Based on the Toxicology of Fluorides,” Proceedings of the Nutrition Society 22: 111–17, http://journals.cambridge.org/action/displayFulltext?type=1&fid=784060&jid=PNS&volumeId=22&issueId=01&aid=784052

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


National Academy of Sciences (1977). Drinking Water and Health. National Academy Press, Washington, DC. pp. 388-389.

Neurath,C and Connett,P (2008) A critique of Douglass’s promised paper on Osteosarcoma. Paper presented at the XXVIIIth. Conference of the International Society for Fluoride Research, Mississauga, Ontario, Canada, September 2008. Abstract titled Current Epidemiological Research on a Link Between Fluoride and Osteosarcoma. Fluoride 2008;41(3):241-2.

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.

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.

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: Response to Paul’s 5th article

This is Ken Perrott’s response to Paul Connett’s last article Fluoride debate: Arguments against fluoridation thread. Part 5. Paul.

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

Paul’s last article was another Gish gallop of arguments and questions he demands I answer.  I discussed the use of the Gish gallop as a tactic for avoidance in my last article. In this article Paul demonstrates how the Gish gallop enables the user to also claim their discussion partner is “ducking” issues and “didn’t address,” “didn’t  acknowledge,” “didn’t comment on” or “didn’t respond to” issues he has raised.

Again, I will not walk into that debating trap and mechanically go through his 30 numbered arguments but will attempt to accommodate as much as is reasonable with some general comments and some specific replies.

Activism and science

This year the fluoridation issue raised questions about the problems of activism for a number of New Zealand scientists. The local scientific community was taken by surprise when the Hamilton City Council in June this year voted to end fluoridation. Surprised because most of us were unaware that the council had decided not to go ahead with a referendum (as we had expected) and instead use a “tribunal” process of consultation. This approach suites activist groups very well. They can be continuously in touch with council decisions, have a membership or contact base that can be organised rapidly and they can saturate such a consultation process with their own submissions.

The Fluoride Action Network of NZ (FANNZ) did this very well. They were able to dominate the consultation process with 89% of the total submissions. (This in a city where referenda have shown about 70% support fluoridation). Being part of Paul Connett’s Fluoride Alert Network they did this on an international scale – about 30% of their submissions were from outside Hamilton with many from outside New Zealand. People like Paul Connett and Declan Waugh made video submissions. These people were promoted as “international experts” or “world experts” on the subject even though they have no credible scientific publications on the subject. Of course local councillors did not have the background to see through that ruse. Reports prepared by the council staff showed the number and international origins of these submissions impressed the council and it’s bureaucracy.

It was easy to conclude that what local scientists lacked was a similar organised activist group. If not specifically devoted to defending the science behind fluoridation then at least to defending science in general. After all, anti-fluoridation activity is not the only area where science gets challenged.

Scientists and health professionals did become active in social communication activity, Facebook, letters to the editor, etc., but I noticed a distinct lack of enthusiasm for any organised activism. No one rushed to form an activist group.

Scientists have a problem with activism because the group thinking and selective use of scientific information inevitably involved is in direct conflict with the scientific ethos. That is why activist scientists tend to face disapproval from colleagues, although this has changed a little recently where the vicious personal attacks on individual climate scientists has made some form of scientific activism essential.

Confirmation bias and activism

Contrary to what many people believe humans are not naturally a rational species. Despite their intelligence and ability to reason they are in practice driven primarily by instinct and emotions. In fact, they would have long become extinct if they relied completely and in all cases on the inefficient and slow process of rationally considering every event that required a response.

This means that confirmation bias and cherry picking information come naturally to us. It is normal to seek information which supports the preconceived ideas and theories we are emotionally attached to. Scientists are just as prone to these human failings as others but the scientific processes help reduce this problem. Scientific ideas and hypotheses are tested by experiential evidence – they are compared against the real world. Theories are judged on their evidential support and not their attractiveness. (This does not deny an important role for speculation). Ideas and theories are exposed to harsh critical consideration by colleagues. All this helps to encourage objectively and reliability of scientific information – while not denying that there are still inevitable residual problems from confirmation bias. The dynamic nature of science and the provisional nature of current theories and ideas, means that over time mistakes arising  from these human frailties can be reduced.

Contrast that with the position of activists, even scientific activists. They are inevitably driven by strong ideological or political aims which naturally encourage confirmation bias and cherry picking. But unlike a scientific researcher they exist in an uncritical, or at least biased, social environment. Group thinking encourages a selective approach to scientific knowledge and a resistance to considering anything conflicting with the activist agenda. While heretics can be encouraged in scientific research they get jumped on in activist groups. Ideas and messages do not get tested against reality – far from it. They are tested for political effectiveness, in the political arena – not the natural world.

In effect, the world of activism is stifling for a person used to the creativity of genuine scientific research. I recognise that at times activism is essential and have myself played an activist role in my past. Now I see it as a necessary evil but not something I could do as a job. I do not envy Paul Connett his job as an executive for an activist organisation. The environment of group thinking and the need to abandon intellectual honesty to the ideological aims of the group are bad enough. But what happens to a scientist in such a position who finds they can longer follow the “party line?” That they no longer “have the faith?” It is a bit like the priest who finds, after years in the job ,they are an atheist. Do they go on hypocritically preaching every Sunday or do they take the honest way out and abandon their job with it’s financial and social security to face an uncertian future?

In scientific research it is expected that we can change our beliefs and ideas in the face of new evidence. Not to do so could lead to loss of scientific prestige and employability. It is the reverse to what Paul would face if he lost his anti-fluoridation convictions.

That is the problem for me – the strong pressure to conform to the activist ideological agenda despite the evidence. I think that colours Paul’s approach to many of the issues in his articles here.

Misleading propaganda

Paul raises the misleading image that was in a Queensland Health brochure again. He sweats blood attempting to imply my approval of that tactic. That is not honest. Especially as I made clear that “I do not support its implied message.” And explained that Paul’s Queensland Health example, and a similar anti-fluoridation brochure I raised, are “extreme exaggerations used to promote a message. Reasonable people should condemn that tactic. “

It is interesting Paul devotes so much time on this brochure in his last contribution to what, after all, is meant to be a scientific exchange, not an exercise in laying guilt for someone else’s transgression.  No one is actually defending the Queensland Health brochure – even Queensland Health! At this stage it seems purely to be a plaything of the anti-fluoridation groups. Paul himself was unable to supply a source or citation yet he had ready access to it and promotes it far and wide.

Don’t know what else I can add – except writing personally to Queensland Health with a complaint. Bit difficult without a citation to its use I could quote. Never mind, my public admonishment here should suffice.

I agree with Paul that we should expect better from our public servants but Paul missed my point “This sort of misrepresentation is probably more common among opponents of fluoridation.” I certainly find misrepresentation by public officials on this subject rare –  anti-fluoride activists make this charge far more often than is justified.

I do not buy Paul’s argument that similar but much more common misinformative propaganda by anti-fluoridation activists is somehow more permissible than the rare piece by a public servant. Especially as we have the power to correct a public servant, submit a freedom of information application, get a retraction and an apology. But try that with anti-fluoride activists and organisations like FAN and FANNZ. No such luck. One is more likely to be abused.

Paul’s complaints in this area would be a bit more convincing if he publicly condemned the misleading propaganda from his own activists. He cannot be unaware of the extreme claims made by members of his Fluoride Alert Network throughout the world. Quite apart from their misrepresentation of the science, which he probably encourages anyway, there are the political and personal harassment of people by sections of his activist network which he cannot be blind to, yet refuses to condemn.

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.

Why is he unwilling to publicly condemn such behaviour?

The Hastings trial

Paul weaves a conspiracy theory around the Hastings’ trial using on one-sided sources and their vague claims. I note that Paul also relies on quotes from letters. He does the same in his book. A colleague analysed the reference list and found many are to newspapers, magazines, newsletters, letters and conversations in meetings (a large proportion are duplicates) (see an impressive-sounding number of references, (therefore good?)). Yet he proudly says “You will note that every argument in this book is backed up with references to the scientific literature – 80 pages in all.” 

I don’t think such vague charges should be the subject of our scientific exchange – especially as they divert attention from the scientific issues involved in planning and interpreting such trials and epidemiological studies. Paul should have looked at the disputes around Colqhoun’s analysis of the New Zealand data. Colqhoun was strongly criticised for reliance on questionable data, crude measurements of caries prevalence and failing to establish residence histories and therefore reliable measures of fluoride intake (see, fir example, Newbrun & Horowitz, 2002). He also placed far more reliance on longitudinal studies than is warranted and was selective in choosing studies which have compared fluoridated and unfluoridated communities.

I looked at the current NZ data, which are similar to that analysed by Colqhoun, in my article Cherry picking fluoridation data. This illustrates a number of things. The national data shows clear differences between children from fluoridated and unfluoridated communities and an ethnic effect attributed to social and economic deprivation. This is just normal school clinic data, without technique standardisation for those making the measurements or proper recording of place of residence. The latter effect probably shows up more strongly after 2004 when a “hub and spoke” dental clinics system was introduced further confusing proper records of likely fluoride intake because one clinic could serve a number of areas – both fluoridated and non-fluoridated. This is a likely explanation for the apparent decline of the effectiveness of fluoridation after 2006.

To illustrate how easy it is to extract data for regions and cities which give meaningless results the plot below shows the data for the Waikato. Clearly the variability in this data, (indicated by abrupt changes year to year) is so large it make interpretation meaningless. Yet this does not stop FANNZ, the local version of Paul’s activist organisation, from hypocritically using just the 2011 data for the Waikato (where by chance children from fluoridated areas show more caries than unfluoridated!). One of their representative end used my graph below, showing the problem of cherry picking, as “proof” for claiming fluoridation increases incidence if caries. During the recent referendum campaigns this misrepresentation by anti-fluoridation activists was rife – yet they consistently ignored or covered up the national data.

There is a lesson in this. Careful and critical analysis of epidemiological data is necessary when considering such data. Effects of technique standardisation and changes, places of residence, mobility of families and diffusion of products from fluoridated into non-fluoridated areas must be considered.

Too often anti-fluoride activists simply select the data that fits their story better. They may even be unaware of what they are doing because confirmation bias is a trap we can all fall into and it can be very tempting if one is simply looking for plots to illustrate an effect. To be fair, I have even seen proponents of fluoridation fall into this trap occasionally.

Margin of safety

Paul mentions margin of safety a lot. He claims that I did not comment on the margin of safety analysis he provided based on the Xiang et al. (2003a,b) study.

Has he not been reading my side of the exchange?

I had put a question to him on his use of this study to determine a margin of safety. After commenting on the quality of the study and the journal Fluoride where it was published I wrote:

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.)”

Paul did not respond so I repeated my question in a subsequent article asking him “about the huge variability in the data and how the hell one can place any confidence on the result drawn from Xiang’s figure.”

Briefly my question related to the figure used by Xiang et al.


This is just another example Paul’s selective use of the literature and selective interpretation of parts of it to justify a preconceived claim he wishes to make. In practice, safety limits and margins of safety must be based on a far more extensive review of the literature and involve far less hand waving than Paul demonstrates in this case.

Bottle fed babies – misinformation again

Several times Paul has raised the issue of bottle-fed infants without describing the problem. Broadly, he is making the common anti-fluoridation claim that the reliance of bottle-fed infants on formula made up with fluoridated water causes normal limits for maximum F intake to be exceeded. Usually activists using this argument will refer to health authorities which they claim recommend that formula not be made up using fluoridated water.

The science for the New Zealand situation is clearly described by Cressey et al (2009) in their report Estimated Dietary Fluoride Intake For New Zealanders by Peter Cressey, Dr Sally Gaw and Dr John Love. It is a straightforward desktop study of the “dietary fluoride intakes for a range of age and gender sub-populations based on New Zealand data.” This is how they described their findings for formula-fed infants:

“The estimates for a fully formula-fed infant exceeded the UL [upper level of intake] approximately one-third of the time for formula prepared with water at 0.7 mg fluoride/L and greater than 90% of the time for formula prepared with water at 1.0 mg fluoride/L. However, it should be noted that the current fluoride exposure estimates for formula-fed infants are based on scenarios consistent with regulatory guidelines, rather than on actual water fluoride concentrations and observed infant feeding practices..”

They conclude “the very young appear to be the group at greatest risk of exceeding the UL.” However:

“the rarity of moderate dental fluorosis in the Australia or New Zealand populations indicates that current exceedances do not constitute a safety concern, and indicates that the UL may need to be reviewed.”

They are conceding that in some cases, some of the time, recommended upper levels for fluoride intake can be exceeded for fully formula fed infants. However they do not see this as a real safety concern.

These conclusions lie behind the current advice from our Ministry of Health on this subject. This takes account of the need for review of current ULs and considers use of fluoridated water safe for fully formula-fed infants. However, they also recommend that if parents are concerned (such as over the risk of dental fluorosis) they should use non-fluoridated water for part of the feeding – a peace of mind matter.

The situation in the US is similar

American Dental Association advises:

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. Parents and caregivers are encouraged to talk to their dentists about what’s best for their child.”

Where parents want to reduce the risk of dental fluorosis they:

can use powdered or liquid concentrate formula mixed with water that either is fluoride-free or has low concentrations of fluoride.

And the CDC advises:

Yes, you can use fluoridated water for preparing infant formula. 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; these bottled waters are labeled as de-ionized, purified, demineralized, or distilled.

This sort of information is often distorted by anti-fluoridation activist propaganda. Very often they claim that authorities like the CDC are recommending as an absolute that parents use non-fluoridated water in preparing formula for infants, and not treat the issue as a peace of mind matter.

Dental fluorosis

Anti-fluoridation activists almost unanimously quote figures for total dental fluorosis (or its equivalent) lumping together everything from questionable to severe. This gives them a nice high figure to promote. But, as I have said before, they use a bait and switch tactic to exaggerate the seriousness of the problem by then considering only the more severe category’s when considering the harm. It is worth actually listening to the anecdotal evidence of practicing dentists on this specific issue. How often do they see fluorosis or similar blemishes which need treatment? And how does this figure compare with the frequency with which they see dental decay serious enough to need treatment? I can think of only one dentist who claims fluorosis is a problem which he often sees and treats – he is an active propagandist for FANNZ. I have caught him telling many porkies about fluoridation and I wouldn’t trust his claims.

Paul attempts to put words in my mouth saying I “claimed there was practically no difference in dental fluorosis prevalence between fluoridated and non-fluoridated communities.” I did point out that the most recent NZ Oral Health Survey found no measurable difference. But I also acknowledged that in general an increase in mild categories is normally observed with fluoridation. What I actually wrote was:

“the incidence of fluorosis for children living in fluoridated may often be the same as, or only slightly greater than, the incidence for children living in non-fluoridated areas.”

This is not a denial of an increase in mild forms of fluorosis as a result of fluoridation. Nor is if a denial that the relatively small difference may reflect the diffusion of the benefits of fluoridation into the non-fluoridated areas through family mobility, poor representation of residence history and the movement of products prepared with fluoridated water.

Paul’s misrepresentation is not the sort of behaviour I expect from a discussion partner in a scientific exchange.

All Paul’s manipulation of figures and his claimed access to the minds and “potential psychological problems for young teenagers” does nothing to change the basic situation. This is that water fluoridation can cause an increase in the mildest classification of dental fluorosis but is generally not thought responsible for the more severe classifications. The later are relatively rare and any increases over recent years is unusually attributed to the wider use of fluoridated toothpaste and fluoride dental office treatments (and their accidental ingestion).

The common anti-fluoridation propaganda gives the impression that the total fluoridation occurrence quoted is all severe and not almost all very mild or questionable. For example, in New Zealand activists often use the figure of 44% occurrence of dental fluorosis when only 2.5% is of any concern.

Selective quoting

I have said again and again that one should attempt to understand the scientific literature intelligently and critically. Hard to do as we all suffer from conformation bias and can’t help being selective. Fortunately working within a scientific community there is pressure from peers who will challenge ones interpretation. This helps encourage objectivity and honesty.

But working in an activist group one does not experience such challenges. If anything there is the challenge to conform with the group thought. Confirmation bias and cherry picking gets encouraged and rewarded. Paul’s activism and bias is very clear in the way he selectively quotes the NRC (2006) report. Just a few examples from his last article in his attempt to justify conclusions he wishes to draw from animal studies using high fluoride concentrations.

“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).” (My emphasis of the bits Paul omitted).

Similarly with Paul’s second quote from the NRC report:

Because many assumptions were involved in estimating the values presented in Table D-2, they should be used with caution. But values support a rat-to-human conversion factor for bone fluoride uptake of at least an order of magnitude.” (My emphasis of the bits Paul omitted).”

Natural and artificial fluoride

Many of people relying on Fluoride Alert for their information are confused about the nature of the hydrated fluoride anion in water. At the mystical end of this confusion is the concept that chemical species derived from man-made process are different in their biological action to that from natural sources, even though chemically there is no difference. At the more “realistic” end there is a refusal to accept that the fluorosilicate anion decomposes on dilution. Then there is the hand waving over the role of calcium that Paul indulges in. He repeats his claim:

“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.”

I have had to repeatedly battle out this argument with anti-fluoridation activists who obviously don’t understand basic chemistry but I find this statement amazing for a chemist who should understand the concept of solubility products and the nature of ions in solution.

Contrary to Paul’s suggestion the relationship observed between natural Ca and F concentrations in groundwaters is usually inverse – F concentrations increase as Ca concentrations decrease and vice versa (see for example Handa 1975Geochemistry and Genesis of Fluoride-Containing Ground Waters in India).  Just what we expect when a solid phase like fluorite or apatite is determining solution concentrations at equilibrium.

Here is what one of the commenters on Paul’s last article, Jo Lane, has to say about Paul’s denial of the presence of Ca in treated fluoridated water:

“Point 20 ) Classic example of pseudoscience. Let’s assume that Paul is correct in asserting that the presence of Ca2+ ions affects F- uptake in the GI tract.

Municipal water supplies in NZ have a target hardness (combined concentration of Ca2+ and Mg2+ ions) of 200 mg L-1. Most of this is Ca2+ as Lime (CaO) is typically used to increase pH in one of the final stages of water treatment.

If water was fluoridated to 0.8 mg L-1 F- (unreasonably assuming there is 0 mg L-1 F- to start with) using CaF2 as a source, the concentration of Ca2+ would increase by 0.2 % as compared to using HFA or NaF as a source of F-. This 0.2% change in Ca2+ concentration will not have any appreciable effect on F- uptake in the GI tract.

Given Paul has a PhD in chemistry I cannot believe that he is ignorant of such basic chemistry and so I am left with the unfortunate impression that he is being deliberately deceptive in the way that he presents his arguments.”

I agree. Sure, the Ca concentration in community water supplies will generally be lower than the target value (which is a maximum) but the principle remains. Replacement of fluorosilicic acid by fluorite (CaF2) as a fluoridating agent would have a minuscule effect on calcium concentrations because there is plenty of calcium from other sources – even is soft water.

Paul’s claim is the sort of thing that even an educated chemist might say if they are ideologically driven. This is the problem with activist groups with their own ideological demands and group thinking. It is easy for even the trained person to fall in to an opportunist use of their speciality. And if, like Paul, they are working as an executive of an activist group they don’t have anyone around them to challenge such distortions.

Irish data and reliance on inter-country comparisons

I am pleased Paul admits to being “hasty” in his dismissal of the Irish data. But there are two issues.

1: His problem was more than haste – I was objecting to his attempt to belittle the data by suggesting the Irish workers were biased. I expressed surprise that he would reject the data with that suggestion in a scientific exchange.

2: He appears confused – despite my clear explanation of the data I used. These was the same as used by Cheng et al (2007) – for just one country (Ireland) but separated into the fluoridated and unflouridated areas – not just using the average that Cheng et al used). Paul describes the data as “comparing tooth decay in the Republic of Ireland and Northern Ireland.” Clearly it did not.

Perhaps Paul’s fixation with Declan Waugh’s discredited comparisons of the health statistics for the two countries was pro-occupying Paul’s mind – or perhaps he wanted to divert the discussion into that area.

I repeat the comparison I used below.

The dotted line in the RH figure is effectively what Cheng et al (2007) used for Ireland in the LH figure.

At the time I explained the problems in making the inter-country comparisons Paul was insisting on:

“Simple comparison of countries obscures all sorts of effects such as differences in culture, history, social and political policies, etc. Such plots are also influenced by changes and differences in dental treatment and measurement techniques.”

However, as Paul raises the issue again it is worth commenting again on the flippant way he and other anti-fluoridation propagandists use inter-country comparisons like this. This is the hand-waving involved in claiming the data shows no effect of different fluoridation policies. I will use a figure from Paul’s book to illustrate the problem.

Paul claims his figure shows no difference between the countries – but did he do anything to check that? Did he actually measure the slopes for the different countries? Or did he just wave his hands and say there is clearly no difference?

Fortunately with so few countries it is relatively easy to compare the slopes. I have done so using the data from the WHO site and found the average decline was 0.17 DMFT/year for fluoridated countries and 0.13 DMFT/year for the non-fluoridated countries. This suggests the decline of DMFT in the fluoridated countries was about 25% greater than in the non-fluoridated countries.

Local anti-fluoridation activists reacted strongly to my analysis claiming it is obvious that the analysis is useless. I am sure Paul will point out that the figure of 25% will not be statistically significant – and I agree. The scatter in the rates of decline among the different countries is very large. On top of that the original data itself is hardly very good with generally only 2 data points for each country.

But if the variation is great enough to make a 25% difference in slopes non-significant then what value do such figures have for Paul’s argument? Using simple hand waving and eye-balling to claim no difference is deceptive because he hides that variation. We just don’t expect such comparisons to show the differences due to fluoridation policies. Variation and the influence of confounding factors have too great an influence.

Paul continues to ignore systemic role

Although he concedes it wrong to create the impression that the current surface or topical mechanism for the beneficial role of fluoridated water on existing teeth is the only mechanism he still persists in ignoring any role for ingested fluoride. Any systemic effect. He asks “why are we forcing people to swallow fluoridated water at all?” He ask why I am “not merely advocating swishing and spitting out fluoridated water, or fluoridated mouthwash or using fluoridated toothpaste.”

I have answered that question several times but Paul continues to ignore my response. He claims my  description of the normal and natural role of fluoride in bioapatites do not get is anywhere. He ignores my reference to scientific reports of the participation of ingested fluoride in improving oral health, especially through its beneficial role before teeth erupt.

Unfortunately Paul cannot get past his emotive description of a social health policy as “forcing” something on people. His naive assertion that normal consumption of water should be replaced by “swishing and spitting out” or by a mouthwash or toothpaste also shows he just does not understand the nature of a social health policy. I discussed this in more detail in my last article.

Hirzy’s conspiracy theory

Paul’s colleague in FAN, Bill Hirzy, is unhappy about my reference to his use of a conspiracy theory – the claim that fluoridation is used as a way of disposing of industrial waste. I was referring to Bill’s claim in his section of Paul’s article:

“Water fluoridation, especially with FSA in the U.S., is not at all about improving dental health; it is rather about U.S. taxpayers paying phosphate producers billions of dollars for the privilege of having our public drinking water systems used to dispose of an acid that would otherwise have to be managed in a hazardous waste facility, and thereby improving the bottom lines of phosphate producers.”

He defends himself by attempting a diversion into USGS data showing 94% of fluoroslicic acid produced as a byproduct by phosphate manufacturers goes to water fluoridation systems.

I don’t doubt those figures. M. Michael Miller, in his article Fluorspar gives similar data for 2004:

“About 38,700 t of byproduct fluorosilicic acid valued at $5.15 million was sold for water fluoridation, and about 1 2,300 t valued at $2.71 million was sold or used for other uses”

Miller’s 75% of byproduct fluorosilicic acid sold for water fluoridation is lower that the 94% Hirzy quotes but the difference could result from some of the material being converted to other products before sale.

So, if a quarter of byproduct fluorosilicic acid, or its conversion products, find markets other than water fluoridation what is it about this quarter which makes it a valuable, saleable product – while the 75% sold for water fluoridation must be classified as a waste product and need a conspiracy for its disposal?

Extensive possibilities for fluorosilicic acid uses

As mentioned above there is certainly a market for fluorosilicic acid,and it’s conversion products, apart from use as a water fluoridation agent. I believe that market will probably increase further because the decline in fluorite sources will increase the use of phosphate ores as a source of fluorine chemicals. This will mean that fluorosilicic acid will become more commonly used as an intermediate in the preparation of many, if not most, fluoride chemicals produced.

Currently fluorosilicic  acid can be used in the tanning of animal hides and skins, oil well acidifying, electroplating, glass etching, as a commercial laundry sour,  sterilising agent, in cement and wood preservatives, in the manufacture of ceramics, glasses and paints, in lead refining, etc. it can also be used to manufacture hydrofluoric acid, another important industrial chemical and intermediate for many other fluorine compounds. It can also be converted to aluminium fluoride and cryolite which are important  in the   conversion of alumina ores to aluminium metal.

Ultimately the fluorosilicic acid byproduct from the phosphate industry could become the Teflon on your frying pan, the refrigerant compound in your refrigerator or incorporated in the many products you use every day.

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.

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