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10) Second Thoughts on Water Fluoridation

Several authors of the studies noted above have advised that the use of fluoride for the prevention of tooth decay be re-evaluated in light of red flags surrounding its health effects. In 2007, two reviews attempted to re-evaluate water fluoridation's purported benefits. The reviews, one published in the British Medical Journal (BMJ) and the other in the dental journal Clinical Oral Investigations, have helped to advance the fluoridation debate by elucidating some (not all) key points which critics have been raising in recent years (10a,b).

According to the BMJ review, the evidence underpinning water fluoridation is of “poor quality.” Indeed, if fluoridated water were defined as a medical treatment — which the authors suggest is a reasonable characterization — there would be insufficient evidence to justify its continuation. As noted by the authors:

“If fluoride is a medicine, evidence on its effects should be subject to the standards of proof expected of drugs, including evidence from randomized trials... There have been no randomized trials of water fluoridation.”

Highlighting the uncertainties surrounding water fluoridation, the authors point out that international tooth decay rates appear entirely unrelated to the water fluoridation status of each country. The authors state:

“Although the prevalence of caries varies between countries, levels everywhere have fallen greatly in the past three decades, and national rates of caries are now universally low. This trend has occurred regardless of the concentration of fluoride in water or the use of fluoridated salt, and it probably reflects use of fluoridated toothpastes and other factors, including perhaps aspects of nutrition.”

In addition to questioning the magnitude of fluoridation’s benefits, the authors point out that -- after 60 years -- its safety has yet to be established. The published studies purporting to prove fluoridation’s safety are, according to the review, “insufficient to rule out all but the biggest effects.” As a result, the authors suggest that:

“In the case of fluoridation, people should be aware of the limitations of evidence about its potential harms and that it would be almost impossible to detect small but important risks (especially for chronic conditions) after introducing fluoridation.”

Consistent with the BMJ review, a review in the journal Clinical Oral Investigations examined the research on fluoridation’s effectiveness between the years 2001 and 2006 and found that water fluoridation “may be unnecessary.” According to the authors:

“For the past 50 years, CWF (Community Water Fluoridation) has been considered the most cost-effective measure for the control of caries at the community level. However, it is now accepted that systemic fluoride plays a limited role in caries prevention. Several epidemiologic studies conducted in fluoridated and nonfluoridated communities clearly indicated that CWF may be unnecessary for caries prevention, particularly in the industrialized countries where the caries level has [become] low.”

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REFERENCES:

10a) Cheng KK, et al. (2007). Adding fluoride to water supplies. British Medical Journal 335(7622):699-702.

10b) Pizzo G, et al. (2007). Community water fluoridation and caries prevention: a critical review. Clinical Oral Investigations 11(3):189-93.

See also: Top 10 Scientific Developments of 2006