Comments from NRC panel members
Dr. Kathleen Theissen (risk analyst and senior scientist at SENES Oak Ridge):
“The NRC committee put together a very thorough evaluation of fluoride exposure in the US, much of which would be applicable also for NZ.
“The NRC committee said, unanimously, that 4 ppm (4 mg/L) of fluoride is not protective of human health and should be lowered. We did not attempt to provide a recommendation for what a safe level would be. To allow anything resembling a margin of safety, various unofficial estimates of a suitable new standard range from 0-0.4 ppm, depending on several considerations, including how best to handle the question of carcinogenicity.
“The NRC committee did not, in any way shape or form, conclude that fluoridation is beneficial or safe.
“We did look at several issues that pertain just to fluoridated water, primarily the concerns about silicofluoride usage. There is too much that is not known about the chemistry (water chemistry as well as biochemistry) of silicofluorides to say that they are safe for indiscriminate administration through the water supply.
“For some endpoints [showing harm], many or most of the studies already involve fluoridated water [at 0.7 – 1 ppm] (osteosarcoma, Down syndrome, bone fracture).
“Although promoters insist that dental fluorosis is not adverse or a health effect, the NRC reviewed at least 8 papers reporting an association between dental fluorosis and an increased risk of several adverse effects.”
“Fluoride appears to have an anti-thyroid effect in some individuals. This may result in persons being clinically or subclinically hypothyroid. Among other problems hypothyroidism in pregnant women can result in the birth of children with lowered IQ. Effects on thyroid function may occur at lower fluoride doses, in people who have iodine deficiencies.”
“l personally feel that the NRC report is relevant to many aspects of the water fluoridation debate… [T]he report discusses the wide range of drinking water intake among members of the population, which means that groups with different fluoride concentrations in their drinking water may still have overlapping distributions of individual fluoride exposure. ln other words, the range of individual fluoride exposures at 1 mg/L will overlap the range of individual exposures at 2 mg/L or even 4 mg/L. Thus, even without consideration of differences in individual susceptibility to various effects, the margin of safety between 1 and 4 mg/L is very low.”
“Most people should minimize their fluoride intake.”
Dr. John Doull (Chair of NRC Panel):
““The thyroid changes do worry me. There are some things there that need to be explored.
“What the committee found is that we’ve gone with the status quo regarding fluoride for many years—for too long, really—and now we need to take a fresh look.
“In the scientific community, people tend to think this is settled. I mean, when the U.S. surgeon general comes out and says this is one of the 10 greatest achievements of the 20th century, that’s a hard hurdle to get over. But when we looked at the studies that have been done, we found that many of these questions are unsettled and we have much less information than we should, considering how long this [fluoridation] has been going on. I think that’s why fluoridation is still being challenged so many years after it began.”
Dr. Hardy Limeback (Head of Preventative Dentistry, University of Toronto):
“In my opinion, the evidence that fluoridation is more harmful than beneficial is now overwhelming and policy makers who avoid thoroughly reviewing recent data before introducing new fluoridation schemes do so at risk of future litigation.”
Dr. Robert L. Isaacson (Professor Emeritus at State University of N.Y.; past president of International Behavioural Neuroscience Society):
“Epidemiological studies suggest that fluoridation of drinking water decreases the number of children at the very bright end of the IQ spectrum and increases the number in the low IQ region.”
“While a number of studies have not found any overall effect of maternal fluoride intake and the birth of children with Down syndrome, suspicions have long been raised by some studies that young mothers might be affected more than more mature mothers.”
“On the basis of this study, if no drinking water were