Foreign substances in your precious bodily fluids

February 9th, 2008 by Ben Goldacre in bad science, references, scare stories, statistics | 48 Comments »

You’ll find fluoride in tea, beer and fish, which might sound like a balanced diet to you. This week Alan Johnson announced a major new push for putting it in the drinking water, with some very grand promises, and in the face of serious opposition.

General Ripper first developed his theories about environmental poisoning and bodily fluids when he experienced impotence, fatigue, and a pervasive sense of emptiness during the physical act of love. He instantly identified the cause: a communist plot to pollute our precious bodily fluids with fluoride.

Bill Etherington MP calls it a “poison“. Campaigners say Nazis used it to subdue people in concentration camps. According to the Guardian’s own (sadly departed) alternative health columnist, fluoride is “in the same league as lead and arsenic.”

The reality is that anybody making any confident statement about fluoride – positive or negative – is speaking way beyond the evidence. In 1999 the Department of Health commissioned the Centre for Reviews and Dissemination at York University to do a systematic review of the evidence on the benefits of fluoridation on dental health and to look for evidence of harm. Little new work has been done since.

They found 3200 research papers, mostly of very poor quality (full references on as ever). The ones which met the minimum quality threshold suggested that there was vaguely, possibly, around a 15% increase in the number of children without dental caries in areas with fluoridated water, but the studies generally couldn’t exclude other explanations for the variance. Of course, the big idea with fluoride in water is that it can reduce social inequalities in dental health, because everyone drinks it: but there isn’t much evidence on that either, the work is even poorer quality, and the results are inconsistent.

So when the British Dental Association says there is “overwhelming evidence” that adding fluoride to water helps fight against tooth decay, they’re with General Ripper. And when Alan Johnson says: “Fluoridation is an effective and relatively easy way to help address health inequalities, giving children from poorer backgrounds a dental health boost that can last a lifetime,” he’s really just pushing an admirably old fashioned line that complex social problems can be addressed with £50m worth of atoms. The people behind the York review have had to spend a fair amount of time pointing out that people are misrepresenting their work.

But since I’m in the mood for some scaremongering, let’s not forget the potential harms. Fluoridation will give around one in eight people mottled teeth (“fluorosis”). And there’s something else to worry about, if you like worrying. An observational study from Taiwan found a high incidence of bladder cancer in women from areas where the natural fluoride content in water was high. It might easily have been a chance finding – the study in question measured lots of variables, and if you measure enough things, then some of them are bound to come out positive, just by chance. But it could be real.

The problem here is one of small effect sizes. You don’t need a careful designed study to show that falling out of a plane will probably kill you, but fluoride and bladder cancer would be a pig to research: because the effect size is small, the exposure is spread over half a century, and the outcome – bladder cancer – takes a lifetime to reveal itself. Welcome to the finer details behind “more research is needed”.

And the fascinating thing about public health is, with population effects, the numbers can start to get very scary, very quickly: in the UK, for example, just a tiny 10% increase in risk would give you 1000 extra new cases of bladder cancer every year. Fear. Actually, I enjoyed that. Maybe I should move to the Mail.


The most readable overview on the poor quality of the data is this article by Cheng, Chalmers and Sheldon. Prof Sir Iain Chalmers founded the Cochrane library, for anyone who seeks to doubt his badassness.

The Taiwan study is here (the authors attribute the increase in risk to a problem of multiple comparisons):

The York review is here. You’ll see that for several years now they’ve been trying to point out that people are misrepresenting their work.

And if you want a particularly good example of someone pompously overstating the evidence, try this doozy from the Sunday mirror.

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48 Responses

  1. stever said,

    February 9, 2008 at 7:36 am

    how about spending that 50 mil on a targeted public health campaign for the evidence based policy of ‘brushing teeth’ and ‘not eating so many sweets’? I have references and everything.

  2. gazza said,

    February 9, 2008 at 5:56 pm

    Interesting because I’d just assumed fluoride in drinking water did help tooth health without checking.

    But I am right in assuming that fluoride in modern toothpastes makes a positive contribution? I’ve also assumed that without really checking because kids often seem to be cavity free nowadays despite the sugar in their diet whilst an oldie like me had gotten a mouthful of cavities in my youth on a much lower sugar diet and no fluoride toothpastes!

  3. Ben Goldacre said,

    February 9, 2008 at 5:58 pm

    it probably does help, a bit, at a bit of a cost, but it’s not very clear.

  4. gazza said,

    February 9, 2008 at 6:08 pm

    Various dentists have, during my visits to them, claimed to be able to guess my age without staring too hard at other signs of physical distress by commenting on my extensively filled teeth and ascribing that to pre-flouride toothpaste (I’m in my 50’s).

    Given that it appears that kids do often seem to be cavity free entering their 20’s what other causes for this apparent improvement in dental health exist?

    Or are things not as improved as my anecdotal evidence suggests?

  5. NickPheas said,

    February 9, 2008 at 7:09 pm

    What I’ve always wanted to know is WHAT Flouride?

    Unless chemistry has changed since my Grade E A-Level, Flourine is the substance, Flouride means an ion in a particular state. But to have that ion in a particular state it needs a partner.

    We don’t call table salt just Chloride.

  6. Katherine said,

    February 9, 2008 at 7:20 pm

    I developed some attractive flurosis as a child, apparently due to living in regions with highly fluorided water; these marks have only just faded in recent years. On the other hand, I’ve nearly reached the grand old age of 30 without a single dental problem. I will admit that 1 is a fairly limited sample size to base opinions on, though…

  7. projektleiterin said,

    February 9, 2008 at 7:37 pm

    That’s pretty interesting. I always thought fluoride in moderation was good and the amount that you get with your toothpaste was sufficient.

    Years ago I was in Tunisia and I noticed that many of the native people there had really bad teeth; the damage seemed to require a more plausible explanation than just lack of dental hygiene. One of the girls in my group asked the tour guide about it and he said it was due to excessive fluoride in water. I don’t know whether the fluoride in the water had a natural source or was there by governmental decree.

  8. Daibhid C said,

    February 9, 2008 at 8:58 pm

    I recall this being discussed in science books when I was at school (with an admirable attempt to provide both sides of the debate and add some personality to the text by means of the characters “Annie Addit” and “Betty Bannit”). It’s amazing we don’t seem to have got any further with “what fluride actually *does*” in the decade-and-a-half since…

  9. raygirvan said,

    February 10, 2008 at 12:11 am

    Natural – see Elements of Medical Geology.

  10. said,

    February 10, 2008 at 1:39 am

    The problem with spending £50M on dentistry is that it wouldn’t be nearly enough. The problem with spending it on health promotion campaigns is that even if people know something is bad for them they still go ahead and do it anyway.
    It’s my understanding that those parts of the country that fluoridate their water supply do have the lowest ‘dmft’ (decayed, missing, filled teeth) rates in the UK and if we fluoridate nationally we’ll be able to determine whether the hypothesised negative effects of flouride (in the low, prescribed doses we will be exposed to) are cause for concern. For the sake of real balance I’d have to say the BDA are on considerably higher ground, evidence wise, than General Ripper.

  11. projektleiterin said,

    February 10, 2008 at 8:15 am

    Thanks, raygirvan! By the way, this Google booksearch is a neat feature. I know it exists, but don’t remember to use it.

  12. superburger said,

    February 10, 2008 at 10:32 am

    “Unless chemistry has changed since my Grade E A-Level, Flourine is the substance, Flouride means an ion in a particular state. But to have that ion in a particular state it needs a partner.

    We don’t call table salt just Chloride.”

    Fluorine is an element. It’s a greeny-yellow gas at room temp and is quite unpleasant to breathe in.

    Fluoride is an anion (negative charged ion) meaning it has gained an extra electron.

    As you point out, it needs to get an electron from somewhere and the simplest is something like sodium or lithium (which lose an electron to form cations) and you end up with pretty inert (but highly soluble) sodium fluoride (sometimes found in toothpaste)

    think water is normally treated with hexafluorosilicic acid (H2SiF6) which is a bit more complex but the idea is the same.

    it’s called fluoride as that’s the bit that does / or doesn’t have an effect on dental health, the other part is essentially a carrier for the fluoride.

    Same reason that people worry about sodium in diets, even though it’s normally consumed as sodium chloride (i.e. table salt).

  13. muscleman said,

    February 10, 2008 at 12:03 pm

    I grew up in New Zealand where reticulated water has been fluoridated for decades. Apparently the soils in NZ are deficient in fluoride (and selenium) and there was terrible dental health.

    It would be relatively cheap to test the bladder cancer theory since many people in rural areas and even on the edges of towns and cities use rainwater (big gutter fed water tanks by the house are a giveaway). Mind you there would be all sorts of confounders, like the use of fluoridated toothpaste. I am certainly not aware of anything having been found and there are a number of long term longitudinal studies like the Milton one which should have flagged up anything properly significant.

    Certainly there hasn’t been an epidemic of fluorosis of the teeth or bones and the point in your Japanese example was how high is the high flouride levels they were consuming? You should know that some dose response curves are far from linear so fluoridating water here might also be below the requisite dose level. Besides people suck on organic fair trade sustainable bottled water these days anyway.

  14. clayton vernon said,

    February 10, 2008 at 12:28 pm

    Ben, can you get into the Guardian the emerging uber-scandal involving the paper by Warda and Han to be in the journal “Proteomics.” You can follow the debunking in ‘Pharyngula.’

  15. David H said,

    February 10, 2008 at 12:45 pm

    Say for the purposes of argument that fluoride in the water reduces tooth decay without harmful side effects. Is there any other area where we forcibly medicate the general population? (by general population I exclude those who are to effete to drink tap water)

  16. notzed said,

    February 11, 2008 at 4:53 am

    So .. is this why you poms have such notoriously bad teeth?

  17. Jessica McLeod said,

    February 11, 2008 at 6:25 am

    I’m really surprised, I guess I just assumed that all first-world countries had this. I live in Australia, and it is pretty well known that people from Queensland (the only state without fluoride in the water) have terrible teeth. In fact, a friend of mine who moved there said that on her first visit to the dentist, the dentist said, “You didn’t grow up in Queensland.”

  18. benb said,

    February 11, 2008 at 12:45 pm

    On the other hand, £50m to reduce national anxiety levels seems like a bit of a bargain!

  19. PlanetaryGear said,

    February 11, 2008 at 2:35 pm

    Part of the fluoridation program in the US is the actual removal, or reduction of it in areas where the levels are high enough to cause “fluorosis” nobody here gets “texas teeth” anymore because those levels are controlled. Is it really true that you’re talking about adding enough to the water to cause that? I was also of the impression that while water fluoridation was rare in Europe, they added it to other things like salt so that peoples intake was about the same as it is here.

  20. emilypk said,

    February 11, 2008 at 3:05 pm

    I would lean towards thinking it does work based on the anecdotal but large sample-based impressions of several school dental nurses I spoke to who say their work load went down quite sharply when flouride went in the water. I bet their records could be mined to give firmer evidence as during that period they checked each kid in the schools they worked for.

    People push education, but education doesn’t help young children with idiots for parents.

  21. Citizen Deux said,

    February 11, 2008 at 3:17 pm

    I am not quite sure I concur with Ben’s assertion of the fluoride evidence. The ADA (US), CDC and WHO all categorize fluoridation as a significant health program. Some of the benefits I have read in meta-analyses are as high as a 40% reduction in caries.

    CDC Study

    They also cite the York study and amounts of fluoride in water supplies (such as in Asia) and consumption rates are also a factor.

    I think the weight of evidence is heavily in favor of benefits.

  22. Squander Two said,

    February 11, 2008 at 4:59 pm

    > Is there any other area where we forcibly medicate the general population?

    Well, there’s vaccination. But I agree with Muscleman that the word “medicate” is somewhat loaded here. So how about, instead:

    > Is there any other area where we forcibly control the content of food or drink consumed by the general population?

    And the answer would then be a resounding yes. We already put chlorine in public drinking water to kill bacteria, for a start. And then we add lime to neutralise the chlorine.

    It occurs to me that, as long as we have the NHS, it’s going to be sensible to do things like this. If we’ve decided — and we have — that it’s the government’s job to manage the public’s dental health, then they should try to do it efficiently. Bunging fluoride in the water (assuming it works as described) is no doubt cheaper than providing the number of fillings it prevents. There’s an argument to be made for getting the government out of the healthcare provision business and putting these decisions into the hands of individuals, but I don’t think that would necessarily entail going so far as to remove the legal imperative to disinfect public drinking water and leave it up to the individual whether to boil their water. There are reasonable minimum standards to be maintained, and I don’t see any reason why fluoridation shouldn’t be considered as one of them.

  23. David H said,

    February 11, 2008 at 7:17 pm

    Regarding Muscleman’s comments:
    Are you suggesting that most of us suffer from fluoride deficiency?
    As regards your daughter’s suspected anaemia (I assume she is a child), yes, you are doing the right and proper thing. Is HMG in loco parentis for us in the matter of fluoride?

  24. superburger said,

    February 12, 2008 at 9:43 am

    “> Is there any other area where we forcibly medicate the general population?”

    Yes, cereals and margarine are ‘fortified’ with vitamins and iron .

    There’s not a lack of dentists in britain per se, it’s a lack who are prepared to do NHS work. (despite having been trained at considerable expense to the taxpayer).

    Plus cosmetic dentistry isn’t free for adults so people won’t pay for braces / whitening / etc.

  25. Fralen said,

    February 12, 2008 at 12:39 pm

    “You’ve given no real evidence for or against the cancer accusations which seem to amount to little more than rumour.”

    It’s not rumour, it’s published ecological data which can be interpreted as chance, or otherwise, as explained in the post.

    Indeed the reference to that Taiwan cancer data is given above too. Moron.

  26. Min said,

    February 12, 2008 at 2:07 pm

    What proportion of a country’s water actually ends up on teeth anyway? Why would you pour chemicals into an entire water supply just so a tiny bit of it might slightly reduce the chances of tooth decay? A proper dental hygiene programme would be a much better use of resources. I’ll bet that social status and culture is a better indicator of dental hygiene than the amount of fluoride in the water.

    What, another attempt to use chemicals to solve complex social problems?

  27. Harlequin said,

    February 12, 2008 at 3:43 pm

    “> Is there any other area where we forcibly medicate the general population?”

    “> Yes, cereals and margarine are ‘fortified’ with vitamins and iron”

    Cereals and margarine are optional – drinking water is not.

  28. projektleiterin said,

    February 12, 2008 at 7:42 pm

    My personal defintion of “bad teeth”:

    – accumulation of plaque
    – caries
    – missing teeth or parts(I saw this video with Paul Potts and while he has a gorgeous voice his teeth are considerably bad. Here it would be people from a really low income class that have teeth like this.)
    – strong discoloration

    I would need braces and my teeth are not perfectly white either, but they are ok and I do not consider bad teeth merely an esthetical problem.

  29. pv said,

    February 12, 2008 at 10:55 pm

    I would like to suggest that biggest danger of fluoride in toothpaste is the increase in the incidence of teeth braces.
    While more than 50 years ago there were more fillings and tooth extractions, there were almost certainly far fewer mouths sporting braces.
    The poor old dentists have to preserve (sorry, I mean increase) their incomes now the demand for filings is so reduced. Do the claims made for having subjectively perfect teeth stand up to any scrutiny? Or are braces for the most part merely a bit of quackery and an easy way to access the contents of someone else’s private bank account?

  30. Citizen Deux said,

    February 13, 2008 at 4:09 pm

    Well, there is a lot of Bad Science in this thread. I am surprised that some of the posters have not taken a deeper look into fluoridation , its history, benefits and the mechanism of dental decay it is designed to fight.

    *By the way countries such as France, Germany, Switzerland and Belgium use salt fluoridation instead. Reference – Elsevier

    Ireland has a great website detailing their history of fluoridation. Given the isolation that nation, I think the data is pretty compelling.

    I am disappointed with the appearance of ad hominem attacks in the postings, generally this site seems to be a refuge of clever, respectful debate. There seems to be an emotional component here in which arguments are magnified beyond the suggestion of the data available.

    The first determination should be whether fluoridation is effective. This fact seems to be well established. The second determination should be whether the risks of fluoridation run counter to and outweigh its benefits. The determination here appears to be no.

    The issue of public consent is a red herring as each implemented program has had a review, comment and acknowledgement period.

    Am I missing something?

  31. emilypk said,

    February 13, 2008 at 6:39 pm

    Not that I can see.

  32. Dr Aust said,

    February 13, 2008 at 8:53 pm

    Isn’t this just a cautionary tale about how difficult it is to do really convincing studies in epidemiology given how many things you have to try and control for?

    The original work on which fluoridation policy was based is old – the landmark studies were done between the mid 1940s and mid 1950s, and fluoridation in the US was widespread by the late 50s, hence General Jack D Ripper in the film (1964). And by modern standards these studies have flaws, though at the time they were state-of-the-art.

    Which doesn’t mean fluoridation is bad – it just means the evidence is lacking.

    Anyway, for some reason I just can’t get all that worked up about whether they stick fluoride in my water or not. Must be the results of that mind-control stuff they’ve been putting in my tea.

  33. Citizen Deux said,

    February 14, 2008 at 3:36 pm

    Do you want to provoke them? Try a sharper stick, use big words and even more subtle innuendo.

    There is a good report on fluoridation using salt from Costa Rica. The original project to fluoridate the water failed due to the problems with infrastructure.

    Personally, I think the focus should be on quality water supplies, elimination of parasites and malaria, globally.

  34. Robert Carnegie said,

    February 15, 2008 at 1:48 am

    Salt isn’t healthy in excess. You’re supposed not to swallow the toothpaste, although probably not because of the sodium fluoride. Fluoride is an ion that tends to abandon its partners and go off by itself. Hard water, on the other hand, may be good for you – I think that’s another point where studies are not conclusively positive – but it isn’t good for your applances. If you’re worried about that, you can stick magnets onto them. Does that help? Studies are not conclusively positive… and so on.

  35. gazza said,

    February 15, 2008 at 9:07 am

    This thread had seemed very hazy for me given the potential health implications of fluoridation.

    It’s been interesting to see the debate on what the ‘state’ should do to items such as water, or common foodtuffs, in order to combat possible health problems in the population. My preference is for the state to keep out of this unless absolutely firm evidence for strong health benefits is made. A case by case discussion point, though a clean water supply is a no-brainer.

    The fluoridation of water and its benefits still seems to be ‘in the air’ in this context. Although there’s some debate on this here, it seems the evidence isn’t as strong as it should be for state intervention to be fully justifiable.

    Where I am disappointed here is on info for evidence of fluoride in toothpaste in preventing decay. No one seems to think it as important as I do! Although I hate to bring the anecdotal stuff up in this column it just seems so clear to me because people of my generation and older had a mouthful of cavities in our teens despite regular brushing and less cheap confectionary as available today (though we did have the sugary drinks….). In contrast many of you younger folks (Ben included) presumably have pristine teeth despite a childhood of chocolate lunches. I would ascribe that generational difference primarily to fluoride toothpaste! Anyone disagree?

  36. kim said,

    February 15, 2008 at 10:59 am

    If the evidence isn’t clear-cut, isn’t it better to err on the side of caution and not fluoridate water? I actually don’t want the government deciding for me that it’s going to look after my teeth. If I’m convinced of the benefits of fluoride, then I can buy fluorinated toothpaste.

  37. gingerninja said,

    February 19, 2008 at 1:28 am

    eh? I’m sure we’ve had fluoridated water here in the midlands/ birmingham for several decades. As far as I’ve been told, it works quite well and people need less fillings than in the past.

  38. melk said,

    February 21, 2008 at 12:42 pm

    You guys don’t have fluoridated water? My wife and I grew up in South Africa and have the normal complement of tooth fillings, i.e., just about every molar. Our two sons were born in the USA and now, in their 30s and like all their friends, do not have a single filling in their mouths. And, no, they do have all their teeth. American dentists have to invent new reasons for their own existence. My brother-in-law is Head of Dentistry at a major US University. The benefits of fluoride are beyond argument.

  39. cisono said,

    March 10, 2008 at 10:52 am

    “The issue of public consent is a red herring as each implemented program has had a review, comment and acknowledgement period.

    Am I missing something?”

    Apparently Yes. I simply do not want fluoride in my water. Full stop. (And no, I don’t agree with your summaries as to benefits and risks!)

    [Bad science] Reviews, comments and acknowledgements… yeah all nice stuff done behind curtains and away from the public. We mainly only get to hear about decisions made afterwards…

  40. microanalyst said,

    May 11, 2008 at 6:15 pm

    Some real science:

    Dental caries results when bacteria breed in mushy sweet food resulting in an acidic plaque contacting with the tooth.

    Tooth enamel is 96% microcrystalline apatite, a mineral with the formula Ca5(PO4)3(OH,F,Cl).

    At the surface of the tooth of an individual never exposed to fluoridation or F in toothpaste the ratio of OH:F:Cl is 90:0:10 This can resist acids down to pH5.5 If all the OH is replaced by F then an acid stronger than pH3.5 is needed. (The lower the pH, the stronger the acid).

    The outer micrometre (thousandth of a millimetre) of teeth in fluoridated areas does contain a high concentration of F (up to 3wt% or 30000ppm). This drops to only 100ppm about 5 micrometres into the enamel.

    Thus the benefits of fluoride result in its action from outside the tooth and there is no need to ingest fluorine.

    These days the improved dental health of children in fluoridated areas amounts to about one less filling by the age of 10. This could be due to rinsing after brushing teeth. The fluorine in the rinsing water hangs around in saliva for several minutes.

    The best way for all generations to look after their teeth is to brush with a fuoride toothpaste and have a good mouthwash with high, 10ppm F water. Stop if fluorosis appears.

    Historical note: An epidemic of dental caries started when cheap refined sugar became available at the end of the 18th century. Because of the naval blockade by the UK of Europe and Napoleon’s “Continental System”, the epidemic was worst in the USA, UK and its colonies, i.e. the English speaking peoples. Caries reached its peak at the time of the first word war and, with the arrival of affordable dentistry and awareness of dental hygiene, declined thereafter. It just happened that fluoridation was introduced at a time when dental health was improving anyway.

  41. marysiakay said,

    February 13, 2009 at 2:17 pm

    My Mum gave us fluoride tablets as kids. I have perfect teeth pretty much, my sister got stains from over fluoridation and my brother has lots of fillings cause he never brushed his teeth. None of this is relevant. I want to choose what I take into my body to the extent that is possible, I don’t want chemicals added to my water any more than is necessary, especially as I don’t drink bottled water I solely drink tap water. Maybe we should put the fluoride in the sweets, after all that’s what causes the problem in the first place… stick it in the fizzy drinks, they’re full of crap already. Or how about primary school children brush their teeth when they get to school every morning, I bet that would make a big difference. My stepmother’s kids will brush their teeth if they’re told, they just never think to do it themselves cause they have no routine, school can give them that routine.

  42. Evelyn Haskins said,

    March 21, 2009 at 12:28 am

    Tooth enamel is composed of Calcium Apatite.
    Unfortunately Calcium atoms are a little too large to fit in well in the crystal structure. So the crystalline stricture becomes warped and hence fragile.

    Fluorapatite however is even weaker, as the fluorine atoms are much too small for the crystalline structure.

    However, if in our tooth enamel a proportion of the Calcium atoms are replaced by the much smaller fluorine atoms, then the crystalline structure becomes much stronger.

    This is why fluoride ions ingested while the tooth enamel is FORMING can increase enamel strength in the teeth. That is before birth for the deciduous teeth and in early childhood for the permanent teeth.

    Fluoride in toothpaste will do little, if anything, to increase enamel strength. It can only work on the4e teeth while present in solution in the mouth. And can only affect the very uppermost layer of the crystalline structure.

    Too much fluorine/fluorine is much worse than not enough. Not only does it weaken the tooth enamel but it causes bone deformities.

    But as far as I know, the only cases of fluorosis that have been reported are from areas where naturally occurring fluoride to very high.

    As to putting it in drinking water — I’m all for it — it would be well nigh impossible to get a toxic dose from drinking water, at the level that it is added to reticulated drinking water in area with NO natural fluoride.

    Obviously, you don’t just bung fluorine in the water — the water must be tested — for an average fluorine content over a period of time. Because, for example, after high rainfall events it is likely to be lower.)

    Tablets on the other hand are easily overdosed on — the old “if a little is good, a lot must be better phenomenon — and an overdose that can be obtained from tablets can be fatal.

    From my, admittedly limited, reading of the research it seems that the “anti-fluoridation” reports are coming from anti-fluoridation organisations. And they are seriously flawed — mostly studies done in areas with very high levels of natural fluoride present in the water, or on very small populations.

    The “pro-fluoride” research seems to be usually done of very larger groups over longer periods.

    And then I really can’t see why a Municipal Council or “Water authority” would be biased in favour of adding fluoride — after all it merely adds an extra expense to water provision.

    The argument that you want to be in control,of what you eat/drink does not hold water either. There is already added chemicals, also with toxic potentiality, added to our water to “make it safe”.
    Natural water can carry many disease causing organisms, as well as many different minerals. Depends on whether of not you are in a hard water area or a soft water area. Rainwater, especially in built up areas can contain many toxic minerals and depending on how you catch it, disease causing organisms.

  43. Evelyn Haskins said,

    March 21, 2009 at 12:39 am

    For those who might be interested in reading some chemistry 🙂
    Drinking Water Containing Fluoride
    The Formation of Hydroxyfluor-Apatite in Tooth Enamel Under Influence of . . .

  44. LindaRosaRN said,

    May 1, 2011 at 12:27 am

    I’m disappointed Dr. Goldacre has given fluoridation such short shrift.

    Actually, few things have been more studied in the public health arena than community water fluoridation. The number of research studies involving fluoride is probably closer to 30,000 than 3,200, with the efficacy and safety of community water fluoridation well established.

    Regarding the “mottling” effect of teeth, the degree of fluorosis is key. What we see in the USA is very mild fluorosis, usually from children eating toothpaste or living in areas with private water wells. Mild to moderate fluorosis is a cosmetic condition, with mottling usually in the form of white patches that indicate strong teeth. (Please pass the mild fluorosis!) Only in severe fluorosis, seen for example in areas of India where there are high levels of fluoride in ground water, is there a weakening of teeth and bones.

    In effect, fluoride is a *nutrient*, but needed only in trace amounts. Here’s the test of that: Without enough fluoride, the tiny bones in the ear will become malformed (a condition that can result in hearing loss), but is reversible by ingesting fluoride.

    Community water fluoridation is merely the adjustment of the fluoride that already exists in drinking water so that it is at a beneficial dosage. Ongoing studies determine what is ideal, based on climate and intake of fluoride from other source.

    I recommend these reviews:

    Fluoride Technical Study Group Report

    Institute of Medicine: Fluoride Technical Study Group Report on fluoride:

    CDC — Community Water Fluoridation

  45. danbdare said,

    October 22, 2013 at 12:40 pm

    forgive me if this has already been addressed, what of the claim that sodium flouride (found in toothpaste) is a toxic waste byproduct of industry? Also, is there any proof/papers/studies to verify whether the Nazis fluoridation control experiment has any weight to it, because, if as it would seem there is no significant study proving the party line that its good for our teeth…?

  46. LindaRosaRN said,

    July 24, 2014 at 8:08 am

    I would like to make a correction. I was wrong about the number of studies on fluoridation: It is closer to 3,200.

    But the problem with the York systematic review remains: it unreasonably discounted epidemiological studies which are appropriate for public health measure like fluoridation.

    Here is a letter responding to the York review in the *British Dental Journal,26 May 2001;190(10):522:

    “Sir,— Having participated in the York review of water fluoridation as a member of the advisory panel, and read the report in its entirety, I am at a loss to identify the supposed ‘changed situation’ that Baldwin of Bewdley refers to in his letter ‘Fluoridation jinks’ (BDJ 2001; 190: 340).
    Baldwin makes no mention of his position as Vice President of the National Pure Water Association. This is not surprising since it is clearly incompatible with his claim to the moral high ground on fluoridation. While he apparently considers the review ‘the most significant piece of scientific work in the history of fluoridation’, his organisation on its web site1 continues to condemn it as ‘a disgrace, a fiasco, and scientific fraud’.

    I cannot agree with Baldwin and his colleagues at the National Pure Water Association. The York team and their collaborators from the University of Wales Dental School must be congratulated on their thorough and comprehensive review. Overall, the review found ‘no clear association between water fluoridation and incidence or mortality of bone cancers, thyroid cancer or all cancers was found’. The report also notes that ‘the best available evidence suggests that fluoridation of drinking water supplies does reduce caries prevalence, both as measured by the proportion of children who are caries free and by the mean change in dmft/DMFT score.

    The recommendation that the research base (mostly from 1945–1965) be strengthened is neither new nor unwelcome, and the Government has asked the Medical Research Council to advise on what further research might be needed. The report of York’s systematic review is available in full at

    Unacceptably high levels of tooth decay continue to blight the lives of too many young children in Britain — particularly those living in poverty. It remains our belief that, given over 50 years experience world- wide of many millions of people drinking fluoridated water, and the absence of any evidence of harm uncovered by York (or any other reputable body), water fluoridation is still the single most effective public health measure available to address the problem.

    M. A. Lennon
    Chairman, British Fluoridation Society

  47. BillyBudd said,

    July 25, 2014 at 4:30 pm

    The York Review’s decision to exclude epidemiological studies is the reason they reached their conclusions on community water fluoridation. This was controversial at the time and remains so.

    It is safe to say that the overwhelming majority of public health scientists disagree with this decision. The CDC has a nice statement on the impossibility of randomized controlled trials for community water fluoridation which for the convenience of readers I quote in its entirety.

    Community Water Fluoridation

    Studies on the effectiveness of adjusting fluoride in community water to the optimal concentration cannot be designed as randomized clinical trials. Random allocation of study subjects is not possible when a community begins to fluoridate the water because all residents in a community have access to and are exposed to this source of fluoride. In addition, clinical studies cannot be conducted double-blind because both study subjects and researchers usually know whether a community’s water has been fluoridated. Efforts to blind the examiners by moving study subjects to a neutral third site for clinical examinations, using radiographs of teeth without revealing where the subjects live, or including transient residents as study subjects have not fully resolved these inherent limitations. Early studies that led to the unexpected discovery that dental caries was less prevalent and severe among persons with mottled enamel (subsequently identified as a form of enamel fluorosis) were conducted before the caries-preventive effects of fluoride were known (255). In those studies, researchers did not have an a priori reason to suspect they would find either reduced or higher levels of dental caries experience in communities with low levels of mottled enamel. Researchers also had no reason to believe that patients selected where they lived according to their risk for dental caries. In that regard, these studies were randomized, and examiners were blinded.

    Despite the strengths of early studies of the efficacy of naturally occurring fluoride in community drinking water, the limitations of these studies make summarizing the quality of evidence on community water fluoridation as Grade I inappropriate (Table 1). The quality of evidence from studies on the effectiveness of adjusting fluoride concentration in community water to optimal levels is Grade II-1. Research limitations are counterbalanced by broadly similar results from numerous well-conducted field studies by other investigators that included thousands of persons throughout the world (256,257).

  48. BillyBudd said,

    July 25, 2014 at 4:39 pm


    Labeling water fluoridation additives is classic name calling propaganda. There is no substance to the claim

    Firstly, the chemicals used for fluoridation aren’t waste. Waste is the stuff that dribbles out the back of the plant with no added investment. Industrial chemical engineers don’t call any product a “waste” if it requires adding capital investment to the management of the product stream. There is a very competitive international market for fluoride products. A few years ago domestic suppliers could no longer compete with overseas sources for sodium fluoride, the most common additive used for small water systems. The same could happen for the other two additives which now are mostly supplied from mines in Florida.

    US water additive sales are unimportant to phosphate rock mining waste disposal. Fluoride water additives represent only about 2% of the total fluorine mined. The fluoride used in water supplies is an inconsequential portion of the fluorine waste.

    If the fluoride were not thus removed it would end up in the ponds called “gyp stacks” where ultimately the land is reclaimed per Florida environmental law. The unused mineral materials are basically buried. 98% of the fluoride from the mining goes there, not to US drinking water. That only 2% of the fluoride in the mined mineral is removed shows that the mining companies are not solving a “toxic waste” problem through fluoridation.

    Sodium fluoride water additive at the moment is predominantly from fluorospar mining. None is produced in the US. It is not a byproduct but rather a primary mining product. My bet is that those who oppose fluoridation would be no happier with sodium fluoride because it is neither waste nor byproduct.

    There are no effective alternatives to community water fluoridation. While the main scientific justification comes from epidemiological studies, the combined weight of the science supporting is overwhelming.