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For more than 70 years, community water fluoridation has been defended as settled science, despite weak evidence of benefit, unresolved health risks, ethical violations and the quiet influence of powerful corporate interests, writes Dr Mark Diesendorf.
CRITIQUING community water fluoridation (CWF) has come to be associated with anti-vaccination positions, although there is no scientific connection between the two. Just for the record, I support vaccination and think RFK Jr is a dangerous nut case. But even nut cases can occasionally stumble on a correct position.
Fluoride is added to water supplies with the intention of reducing tooth decay in children. This practice is prevalent in a small minority of countries (such as Australia, the USA, New Zealand, Canada, Ireland and Singapore). However, in almost all of continental Europe, CWF has never been implemented or discontinued on grounds of health hazards or ethics.
A leading European opponent was Dr Arvid Carlsson, the Swedish pharmacologist who won the 2000 Nobel Prize in Physiology or Medicine. He opposed CWF on grounds of lack of individual dosage control, potential neurotoxicity and uncertainty about long-term systemic fluoride exposure.
When CWF was introduced into Australia, many medical doctors opposed it with letters published in the Medical Journal of Australia. Their concerns were medical ethics and potential risks. They were ignored and CWF was imposed top-down. How?
Vested interests
CWF was initiated and supported by powerful vested interests who manipulated the science and suppressed the results of contrary research.
Early research, which appeared to show there was less tooth decay in naturally fluoridated regions of the USA, was funded by the aluminium industry, whose smelters emit fluoride (gaseous and particulate) with serious environmental health impacts on plants, wildlife and livestock.
This research spanned 26 states, but the published report by dentist H Trendley Dean only gave results for cities in four states. Despite this selection bias, the research and subsequent implementation of CWF changed the image of a major environmental pollutant to a health benefit. The aluminium industry’s investment paid off.
A major continuing funder of pro-fluoridation research and propaganda is the sugary food industry that benefits from the notion that children can eat junk food while allegedly protected by CWF. Internal documents from the sugar industry and dental organisations reveal their joint manipulation of scientific research. Their methods were later taken up by the tobacco industry.
Alleged benefits
The enthusiastic promotion of CWF for over 70 years has never been supported by a double-blind randomised controlled trial (RCT) of its alleged benefits.
Cochrane Reviews are the gold standard in assessing medications and medical procedures.
Because of the paucity of good epidemiological studies, the latest Cochrane Review expressed uncertainty about the alleged benefits of CWF, finding that:
‘Studies conducted after 1975 showed that adding fluoride to water may lead to slightly less tooth decay in children’s baby teeth. We could not be sure whether adding fluoride to water reduced tooth decay in children’s permanent teeth or decay on the surfaces of permanent teeth.’
This is not strong evidence.
CWF proponents either ignore the Cochrane Reviews or claim that CWF had enormous benefits several decades ago, but nowadays plays a lesser role because of the benefits of fluoride toothpaste.
Indeed, the earlier (2015) Cochrane Review reported larger benefits but added:
‘We had concerns about the methods used, or the reporting of the results, in the vast majority (97%) of the studies.’
The North American “trials” of CWF conducted in the 1940s and ’50s, often cited as classic demonstrations of “enormous” benefits, have been thoroughly discredited for their poor design by dental researcher Philip Sutton, a Doctor of Dental Science, the highest dental research degree in Australia.
CWF proponents also celebrate the large reductions in tooth decay observed in many fluoridated regions around the world in the 1960s, before fluoride toothpaste became widely used. However, they omit to mention the similar large reductions in many unfluoridated regions during the same period. The actual cause of these simultaneous reductions is unknown, as is the cause of the decline in the prevalence of tuberculosis in the first half of the 20th Century.
RCTs find fluoride toothpaste reduces tooth decay, but, as it has 1,000 times the fluoride concentration of fluoridated water, this tells us nothing about the latter’s benefits. The action of fluoride toothpaste is “topical”, dental jargon for “on the dental surfaces” — it is not intended to be ingested.
There is no strong scientific evidence of dental benefit from ingesting fluoride. That its dental action is only topical and not systemic is supported by a well-designed experiment on rats, which bypassed the mouth to deliver fluoride systemically and found no benefit.
Fluoride is neither necessary nor sufficient for sound teeth. Before they were colonised, many Indigenous peoples around the world had excellent teeth despite negligible fluoride in their drinking water or food, while nowadays some people have rotten teeth despite ingesting fluoridated water. Furthermore, fluoride is not a nutrient.
Ethics
CWF is mass medication with an uncontrolled dose, a violation of medical ethics. It’s a medication because it’s used to treat the person, not to make the water safer to drink like chlorination. Although fluoride concentration is controlled at about 0.7 mg/litre, the daily dose depends on the amount of drinking water ingested. Outdoor workers, athletes and people with certain health issues ingest much more than average.
Two adverse health impacts
No RCT has investigated adverse effects. However, RCTs are not necessary to justify banning a medication. There is a large body of lesser evidence suggesting harm from chronic fluoride ingestion, including prospective studies. Here we outline two out of several adverse health impacts.
Skeletal fluorosis, a disease of bones and joints, has been extensively investigated in several countries (notably China and India, but not Australia or the USA) with significant levels of natural fluoride in drinking water. CWF proponents claim this disease only occurs where fluoride concentrations in drinking water are “high”, but actually there is a linear dose-response relationship with no threshold over concentrations 1.2 to 4 mg/litre.
Over much of this range, the daily doses of patients in these countries overlap with those ingested by people with high water intake in Australia. The latter people have no safety margin.
Proponents also misrepresent the evidence for neurotoxicity. Dozens of studies find an association between reduced children’s IQ and chronic fluoride ingestion. Meta-analysis reviews by Harvard University researchers (Choi et al. 2012; Grandjean & Landrigan 2014) and the US National Toxicology Program (2024) broadly support the results of these studies.
The latter report found that, of the 72 studies reviewed, 19 ‘were considered to be high quality; of these, 18 reported an inverse association between estimated fluoride exposure and IQ in children’. In other words, in plain language, fluoride lowers IQ.
Conclusion
Medical and public health authorities accepted uncritically the shoddy dental research on risks and benefits of community water fluoridation. It appears that, with lobbying by vested interests, this led to political support.
CWF has no systemic benefit; it may at best have tiny topical benefit. It’s a neurotoxin and causes skeletal fluorosis in some people who drink a lot of water. It violates medical ethics. It’s supported by poor quality manipulated research and publicity funded by vested interests.
Dr Mark Diesendorf is Honorary Associate Professor of Environment and Society at UNSW Sydney and author with Rod Taylor of The Path to a Sustainable Civilisation (Palgrave Macmillan, 2024).
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