Fluoride Action Network

National Research Council (2006)

An overview of the NRC's groundbreaking report on fluoride toxicity, including excerpts of its key findings and recommendations, statements from the panelists, and a discussion of its relevance to water fluoridation and sulfuryl fluoride.

Relevance to Fluoridation

The NRC panel was tasked with determining the adequacy of EPA’s Maximum Contaminant Level Goal (MCLG) for fluoride (4 ppm) and not with examining the risks and benefits of water fluoridation. With water fluoridation, fluoride is added to water at about 1 ppm in an attempt to reduce tooth decay. Because the level of fluoride added to water in artificial fluoridation programs is less than the MCLG, some have questioned the relevance of the NRC’s report to fluoridation. A thorough review of the NRC’s 450-page report, however, shows that the panel’s findings are highly relevant and important to any consideration of water fluoridation.

The following are ten relevant concerns:

1) The disappearing “margin of safety.” The gap between the level at which fluoride is added to water, ostensibly to protect teeth (1 ppm), is already very close to the level at which the EPA requires fluoride to be removed (4 ppm). The NRC’s recommendation that the MCLG be lowered will make this gap even smaller and thus even more relevant to water fluoridation at 1 ppm.

2) Dose cannot be controlled. The small gap between the MCLG and fluoridation becomes even more significant when recognizing that, although engineers can usually control the level of fluoride added to water (although there have been accidents), they cannot control how much water people actually drink. Nor can they control the fluoride that people get from other sources such as dental products and treatments, processed foods and beverages, fluorinated medications, pesticides and air pollution. As a result, people living in fluoridated communities can receive doses that overlap the doses that people living in areas with 4 ppm can receive.

3) NRC data shows that some children and infants can exceed safe dosage in fluoridated areas. The MCLG of 4 ppm was derived in the 1980s based on the view that the maximum “safe” dose of fluoride for an adult is 8 milligrams per day and the assumption that adults drink 2 liters of water per day. To apply this dose to infants and children (who weigh much less than adults), the dose is expressed in terms of a dosage (mg per kilogram of bodyweight per day). When expressed in terms of dosage, the maximum safe dose is 0.114 mg/kg/day. As NRC’s exposure analysis shows, many people — particularly infants — exceed this dosage on a regular basis, even at 1 ppm.

4) Adverse Effects at low exposures. The extensive NRC report reviewed many animal and human studies where adverse effects on a variety of tissues and organs have been observed at relatively low levels of exposure to fluoride. Many of the effects were observed at lower water concentrations than 4 ppm, lower doses than 8 mg per day, and lower dosages than 0.114 mg/kg/day. These included increased uptake of aluminum into the brains of rats exposed to fluoride at 1 ppm; lowered IQ in children in Chinese studies at levels of 2.5-4.0 ppm; increased hip fracture rates in the elderly at levels between 1 and 4 ppm and lowered thyroid function at dosages as low as 0.01 mg/kg/day. As water intake is random and intake cannot be controlled, all of these studies become relevant for water consumption at 1 ppm.

5) Bone fractures. Hip fractures in the elderly were observed a) in Finland at water levels at or greater than 1.5 ppm (Kurttio, 1999); b) increasing in what appears a linear fashion between 1 ppm and 4.3 ppm in China (Li et al., 2001) while c) bone fractures (of any type) were found to increase between 1.5 and 5.5 ppm in Mexico (Alarcon-Herrera et al., 2001). While the panel did not feel they had enough data to state exactly at what level hip fractures would increase, it did describe both the Kurtio and the Li studies as good studies. When the EPA does its health risk assessment on this issue they will have to take these studies into account. What the NRC report did was to point out that 4 ppm is not protective against bone fractures for a lifetime exposure. It did not indicate what level is protective against bone fractures for a lifetime exposure.

6) Thyroid function. Even more serious is the discussion the NRC provided on fluoride’s impacts on the thyroid and the brain. For the thyroid gland the NRC panel discusses effects at levels 10 times lower than the purported safe dosage (0.114 mg/kg/day) and which are exceeded by millions of American children and adults drinking water at 1 ppm. Based on these observations, it is not clear why the NRC panel did not recommend a safe level of fluoride lower than 1 ppm. Their failure to do so appears to hang on the assumption that the findings on thyroid function in the peer reviewed literature in Europe, Russia, and China may not apply to people in the US. We can always do with more research to confirm scientific/medical findings, but the lack of research on these issues in the US should not leave us with any confidence in the current situation. Indeed, it should be a matter of grave concern that this research has not been done here, even though the artificial fluoridation program has been going on for over 60 years and, as early as 1940, researchers were already writing about fluoride’s impact on the thyroid gland (DeEds, F., 1940).

7) Huge data gaps. The NRC panel makes many research recommendations which reveal huge data gaps in basic research on fluoride’s toxicity in the US. What it didn’t say is that the US Public Health Service’s 60 year-promotion of water fluoridation has severely limited meaningful research into fluoride’s health effects. Most of the research money has been spent on dental research with little or no attention to other body tissues and organ systems.

As the NRC panel’s research recommendations indicate, no significant efforts have been made in the US to track the levels of fluoride in urine, plasma or bones of the American people. Such basic baseline research is critical if one wishes to seriously explore whether there is a connection between fluoride exposure and health effects reported in the literature such as hypothyroidism, neurological effects, arthritis or other conditions afflicting millions of people. In the US, we are flying blind on these matters. Hopefully, the NRC’s review will stimulate some serious research by independent scientists (not those chosen to support the interests of the fluoridation program) in the future.

8 ) Uncertainties. The NRC panel has strongly recommended that the US EPA conduct a health risk assessment in order to ascertain a new MCLG which is protective of the American people — and that includes more vulnerable subsets of the population, including infants, the elderly, and those with diabetes, kidney impairment or heart disease. Because the NRC report has highlighted very serious concerns and uncertainties about fluoride toxicity, when the EPA does an updated health risk assessment on these endpoints, these uncertainties alone warrant the application of a robust margin of safety, which would inevitably produce an MCLG lower than the 1 ppm now used in fluoridation programs.

9) The lack of significant benefit from fluoridation not examined. The assumption that all is well with water fluoriation because the NRC panel did not examine this practice is highly misleading. Had the panel members been required to look at the benefits they would have been shocked on how poor the science is that supports this practice. According to the UK York Review (2000) there is not one grade A study. The gold standard for proving the benefit of a purportedly therapeutic medical treatment is a randomized trial. Yet, despite 60 years of fluoridation, the British Medical Journal recently pointed out that “there have been no randomised trials of water fluoridation.” (Cheng 2007).

The NRC might also have been surprised to find that most European countries do not fluoridate their water but according to WHO figures their children’s teeth are just as good if not better than ours. Moreover, the largest study of tooth decay in the US, conducted by the National Institute of Dental Research (NIDR), could find very little difference in the permanent teeth of children who had lived all their lives in fluoridated compared to non-fluoridated communities (Brunelle and Carlos, 1990). To this we can add the fact that US cities which have been fluoridating for years are reporting a dental crisis, which reflects the fact that a much stronger relation exists between tooth decay and standard of living than one can ever find with ingested fluoride.

10) The fluoridating agents in water fluoridation programs. Also as a consequence of not reviewing the water fluoridation program, the panel did not have to deal with the fact that the chemicals used in water fluoridation are not the same as the fluoride that occurs naturally in some water supplies. The chemicals used are contaminated industrial grade materials, which do not occur naturally, but are obtained from the scrubbing liquor of the pollution control devices of the phosphate fertilizer industry. These contaminated silicon fluorides have received little significant toxicological testing, on the flimsy grounds that once diluted the silicon fluoride compounds will completely dissociate into free fluoride ions and the contaminants will all be below levels of concern, even though some of them like arsenic and lead have an MCLG of zero and thus should not be deliberately added to the water supply

Conclusion: On many fronts, this important review from the National Academy of Sciences is of the utmost relevance to water fluoridation. There is such a small margin of safety between a small benefit to teeth and a huge risk to health that it is time to halt this practice forthwith. Calling for more research after it has been halted is fine. But to do that research while we continue to dose 180 million Americans daily without firm knowledge of what levels will cause damage to health is preposterous. It amounts to the largest experiment with the public’s health ever conducted. If nothing else it violates the Nuremburg Code which strictly forbids human experimentation without the informed consent of the patient. The vast majority of individuals being exposed have never given their consent, and, until now, very few have been fully informed on the downside of overexposure to fluoride.

Other Analysis on the Relevance of the NRC Report to Fluoridation:

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