The fluoride debate – what do the experts say?

The impending High Court decision on the legality of fluoridation in Taranaki, and Paul Connett’s current speaking tour in New Zealand is bringing the fluoridation issue into the news again. New Zealand’s Science Media Centre (SMC) responded by conducting a Q&A with public health experts on fluoride. Here are the results.

Professor Barry Borman

Associate Director, Centre for Public Health Research, Massey University (with Ms Caroline Fyfe), responds:

Given the body of scientific evidence available, are you convinced that water fluoridation is an effective public health intervention?

“The overwhelming evidence from the peer-reviewed literature is that community water fluoridation is a highly effective and cost effective public health method for improving the oral health status of a population.”

What are the main benefits of fluoridation in New Zealand?

“Improving the oral health of the population, especially among those populations which have a poor oral health status, for example those on low incomes.”

What is at stake if more communities choose to end the practice?

“Depriving their local population of a cost effective method for improving (and/or maintaining) the oral health.”

Why do you think water fluoridation continues to be such a heatedly debated issue?

“Primarily because of the engrained views held by both the anti-fluoridation and pro-fluoridation groups, together with a lack of understanding and appropriate interpretation of the literature and nuances involved in the many studies. In many instances, results from the literature are used to support a view, but many of the studies have used poor study design, lack validity, and have varying degrees of bias. It is the validity of the study design that is critically important and not just the focus on the results.

“For example, a number of studies have been carried out in areas where the naturally occurring high levels of fluoride (eg, China and India) are well in excess of those used for community water fluoridation in New Zealand. Some studies adjust for the potential effects of all sources of fluoride, while others don’t, while some make an adjustment for differences between study and control population, while others don’t. The results from a recent meta-analysis showing a relationship between water fluoridation and children’s IQ have been widely used to support the position of the anti-fluoridation lobby, However, the study results have been shown to be flawed in a number of aspects (Borman B, Fyfe C. Fluoride and children’s IQ, NZ Med J, 2013).

“Much of the current confusion over community water fluoridation can also be attributed to the poor communication of the science by scientists.”

What should public health officials be doing to more effectively engage the public on this issue?

“Develop a greater understanding of the principles and techniques of risk communication and how a population perceives a risk to their health. The old adage remains: the things that scare people are not necessarily the things that kill or harm them.”

Professor Murray Thomson

Professor of Dental Epidemiology and Public Health, University of Otago, responds:

Given the body of scientific evidence available, are you convinced that water fluoridation is an effective public health intervention?

“Yes. It is important to remember that community water fluoridation is not a “magic bullet”, though; it will not eliminate tooth decay, but it will reduce it. How? Tooth decay begins as very small “etchings” of the dental enamel; these occur as dietary sugars are fermented (turned into weak acids) by bacteria within the plaque biofilm which forms on the tooth surface.

“Once those sugars have been used up, that demineralisation can be counterbalanced with subsequent remineralisation by calcium and phosphate ions from the saliva, slowly replacing the minerals which were lost. There is a continual cycling between demineralisation and remineralisation; the longer spent in the former, the greater the chance of a cavity. If fluoride is present, it not only enters the enamel, making it more resistant to acid attack, but it also inhibits demineralisation and the plaque bacteria.

“NZ evidence of fluoridation’s effectiveness has come from a number of studies which have shown that not only is decay experience lower among children living with community water fluoridation, but socio-economic inequalities are also lower. Data from our most recent national oral health survey provide evidence for a considerable effect in adults as well – and this effect is becoming more important as more and more Kiwis retain their teeth into old age. The benefits are there for Kiwis of all ages.”

What are the main benefits of fluoridation in New Zealand?

“Lower dental caries rates among children and adults alike. Fewer small children having to have teeth removed in hospital under a general anaesthetic. In area without community water fluoridation, children who do have to have that done present with more decay and at a younger age. Systematic reviews of the international evidence show that adults drinking fluoridated water have 27% less tooth decay experience. Given that the average middle-aged NZ adult has had 18 decayed, missing or filled teeth, that’s a difference of 4 teeth affected, on average.”

What is at stake if more communities choose to end the practice?

“There will be much more tooth decay, and that will have its greatest impact among people living in socio-economically deprived areas, as well as among Maori and Pacifika. It won’t happen overnight, of course, given the chronic, cumulative nature of the disease, but it will definitely get worse. Those who are opposed to community water fluoridation assert that we don’t need it: they argue that people can take fluoride tablets, brush with fluoride toothpaste and use mouthrinses if they want to use fluoride to prevent decay.”

“That’s all very well for the ‘worried well’ in the middle classes (who tend to have more positive self-care and health behaviours anyway), but it is neither feasible nor humane to leave the rest of the population to it. For example, we know from the 2009 national dental survey that only 59% of adults in the most deprived 20% of neighbourhoods brush their teeth twice daily with fluoride toothpaste. There is therefore a role for the State in preventing tooth decay in the NZ population: community water fluoridation remains the most efficient, effective and rational way to do it.”

Why do you think water fluoridation continues to be such a heatedly debated issue?

“There is a small but very vocal minority who have an anti-science, anti-public health agenda. They are very good at targeting the local body politicians who have to make the decision on whether to fluoridate or not. Being single-issue zealots, they have plenty of time and energy to do so. They are also funded well enough to bring overseas rhetoricians/polemicists into NZ periodically on speaking tours.”

What should public health officials be doing to more effectively engage the public on this issue?

“That’s a good question. The doggedness and sheer persistence of the anti-fluoride lobby means that public health officials could easily spend all of their time on the issue, but they actually have a plethora of more pressing, relevant public health issues to deal with, such as dental caries, tobacco, our alarming and rising obesity rates, and so on.” 

If you would like to contact a New Zealand expert about fluoride, please contact the SMC (04 499 5476;

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14 responses to “The fluoride debate – what do the experts say?

  1. Refreshingly no opposing “expert” appears!!


  2. Pingback: The Daily Blog Watch – 5/6 February 2014 « The Daily Blog

  3. John’s anti-fluoride position is not new – he is just hanging his arguments on Connett’s visit.


  4. I wonder how he got there?
    Five years ago I was a passive supporter of fluoridation of drinking water because I accepted the word of public health officials that fluoridation helped reduce dental decay and improve dental health for us all.

    Accepted the word? Funny way to put it.
    Minto seems to think that those in public health just say stuff and we meekly accept it. That’s not what happens. Medical communities don’t get to just make an announcement from on high. They’re not priests. There’s work involved. Actual scientific work. It’s not possible to create a scientific consensus or overturn a scientific consensus any other way. There are no short-cuts.

    “Five years ago I was a passive supporter of evolution because I accepted the word of scientists that evolution worked.”
    “Five years ago I was a passive supporter of the moon landings because I accepted the word of NASA officials that they really went there.”
    See the problem?

    Although I’d never studied the issue I have a background in science and I would have agreed with last year’s statement from the Prime Minister’s Chief Science Advisor Peter Gluckman who said the science was “settled” in favour of fluoridating water supplies.

    Fair enough but there’s lots and lots and lots of issues Minto has probably never studied. Life is short. How much effort has Minto poured into investigating 9/11 or the Heliocentric Theory or cell phones giving you cancer?

    However since then, and more by accident than design, I’ve taken some time to look at the science for and against fluoridation and I’ve changed my position.

    And herein lies the problem. Minto has looked at the science, ladies and gentlemen, and has found it wanting. Oh, the horror!
    Minto has managed to convince himself that he’s found “them” out.
    Just like he could have found “them” out on any other crackpot issue out there bouncing around on the internet.
    It never occurs to Minto that he could possibly be wrong.

    There’s are is a mounting body of scientific evidence which…

    No there isn’t.
    It’s possible to independently verify these things. Papers get published. New data is constantly being gathered on all sorts of things. If you personally feel that you see something clearly that “they” don’t, then you have to consider the very real possibility that you are fooling yourself. You have to use a methodology that doesn’t potentially lead you down the garden path of confirmation bias and conspiracy mongering.
    If you are right about the moon landings being faked or vaccines causing autism and there’s a “mounting body of evidence” then…what’s the mechanism?
    How come “they” aren’t way ahead of you? Is there a cover up? Fraud? Negligence on a global scale? A scientific elite blah, blah, blah?

    On Tuesday night this week I went to hear Emeritus Professor of Chemistry Paul Connett speak…

    Why should you or anybody else care what Connett has to say?
    Are you going to merrily trip off to listen to Kaysing or Wakefield or Duesberg next?

    I was fascinated to hear Connett speak…

    I’m sure he was riveting. Very charismatic. Ken Ham can be a real charmer too. Yet not once did you question whether turning your back on the scientific community in favour of this Connett person was a good idea or not. Why trust him? Why let his patter convince you?
    In science, only the work counts. All the fireside chats in the world don’t amount to a hill of beans. It’s not the speaking tours nor the vanity press books nor the blog articles.
    It’s the work.

    Eight years into the study correspondence shows the researchers were unable to… blah, blah, blah.

    Yes, Connett gave you some anomoly or other and you swallowed it.
    Could have been a graph or a grainy photo of the Eagle lander or an email or something else.
    By appealing to your ego, he’s made you turn away from the scientific consensus. After all, how could you be fooled? You’re too smart for that, right? You’d never make the mistake that other people exactly like yourself have made on so many other issues. After all, you have a background in science. That’s an ironclad guarantee that you can’t be suckered by a snake-oil salesman.

    I’m not suggesting this is a science end point but should be an urgent spur to higher quality studies to confirm/adjust/reject these findings.

    Yes, you are the stalwart saviour. “They” have dropped the ball and you can see it clearly now. Fortunately, you are there to spur “them” into doing their job. Shame on “them”. All of the relevant medical communities on the planet failed. Only you (with the help of Connett) see the awful trooth. You never entertain the idea that perhaps you’ve been conned.

    This is serious stuff. It is not the stuff of “flat-earthers” or climate-science deniers.

    Really? Then what exactly is it that you are doing that is so very different from the flat earthers and the climate science deniers?
    How is your methodology different from theirs?

    You went to a talk by Connett.
    They go to a talk by Monckton.
    Same diff.
    Connett reveals the awful trooth about anomoly “X”.
    Monckton reveals the awful trooth about anomoly “Y”.
    Same diff.
    You now turn your back on the scientific consensus in favour of some guy with a blog.
    Job done.

    Everything you’ve said is taken from the concerned crackpot handbook.

    “….to dismiss critical studies of vaccines and claim the science is “settled” in favour of vaccines when a dispassionate look at the evidence raises lots of important and worrying questions. The science is changing. For example there are now studies which show HIV infections are greater when it is treated with conventional medicines compared to natural remedies. Doesn’t the science here warrant greater examination of alternatives to conventional treatments?
    So why have NASA officials overstated the reality of the moon landings and poured scorn on those that see serious problems? Dr Kaysing was asked this and said the only thing he could suggest was that these officials are worried that if they “lose” the moonlanding battle then issues such as global warming would come under much closer scrutiny.

    Ken Ham described the late Immanuel Velikovsky as one of science’s heroes. Velikovsky initially supported evolution only to move strongly against it after undertaking in-depth research which examined the evidence in America and overseas and found it unconvincing. Velikovsky spoke out against evolution when it was even less popular to do so than it is now. But things are changing. It was good to hear from one doctor at the meeting who spoke publicly against banning smoking in hospitals and also good to hear of the large number of others who oppose it in private.
    I no longer think the science is “settled”.”


  5. Cedric, I suggest take you also that over to The Daily Blog.


  6. duh, a moment of commenting dyslexia (…suggest that you also take that over…)


  7. Good one. Superb passive trolling from yours truly


  8. Done. Thanks for the suggestion.


  9. Done. Thanks for the suggestion

    Even Andy weighed in, staunchly doing his bit for the klimate krazies.


  10. Yes I did my bit for Teh Krazies


  11. Problem here is that NZers like to bury their head in the sand to most things – fluoride, the climate science scam and other things. As if NZ isn’t a 3rd world country, so if the govt ONLY tells you that fluoride is safe – they all jump on the bandwagon like sheep to accept it without any proof whatsoever. Kiwis don’t question anything at all — just follow like sheep – so there will never be any Kiwis who can actually THINK for themselves — or should I say very few out there. The ones that CAN are called conspiracy theorists and in all reality, there was a study that shows that the conspiracy theorists are more sane than those that are not. As for fluoride, lets please look at research from this century rather than old stuff promoting the toxin from the 1960’s people. Get with the program. Times have changed and the research has changed.


  12. Reggie – specifically what research has changed? and in what way?

    If you have been reading the articles here, as well as my debate with Connett, you would nto be making the claim that we are ignoring the research. It has been at the centre of our discussion


  13. Problem here is that NZers like to bury their head in the sand to most things – fluoride, the climate science scam and other things.

    Yes, flouride, the climate science scam and other things.
    Sounds interesting.
    Perhaps Reggie has details on the nuts and bolts of the operation?
    How does it work?
    What’s really going on?

    …so if the govt ONLY tells you…

    Yes, the govt. They tell and we obey. ‘Cause that’s how they do it.
    All of it.

    The ones that CAN are called conspiracy theorists and in all reality, there was a study that shows that the conspiracy theorists are more sane than those that are not.

    Yes, “that study”. That study thing. Therefore conspiracy theorists are more sane.
    Okey dokey. Let’s roll with that.
    How does the global scientific conspiracy work, Reggie?


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