Thursday, January 17, 2008

Top 10 Scientific Developments of 2007

This is a post I read from TeamSizzle forum, postded by Marilyn Vine.


FAN Bulletin 925: Fluoride: Top 10 Scientific Developments of 2007 - January 17, 2008

Dear Supporter,

Today, the Fluoride Action Network (FAN) posted a new review of the "Top 10 Scientific Developments" in 2007. To access a copy of the review, click here.

As detailed in the review, 2007 was another important year in fluoride research, with studies not only questioning long-held views about fluoride's purported benefits, but raising new concerns about its impact on human health. We have posted an excerpt of the review below, detailing some of the new research on fluoride's effect on the brain. (Our review does not include the 19 Chinese studies on fluoride's brain effects that FAN translated in 2007. Many of these will be appearing in an upcoming volume of the journal Fluoride sometime later this year.)

While some toxicologists might be willing to ignore such a large body of literature if they were looking at an additive to motor oil, or dealing with a drug designed to prolong the life of someone with a terminal illness, it would be utterly reckless, in our view, to do so when dealing with a substance added to the drinking water of every man, woman and child. And yet, that is what is happening with water fluoridation. Those who do not have an invested interest in defending fluoridation can see this and that is why so many are signing the Professionals' Statement calling for an end to water fluoridation worldwide.

Paul Connett

p.s. If you know of a science or medical professional who may be interested in signing the Professionals' Statement, please send them the Statement and FAN's latest review of the research.

1) New Evidence on Fluoride & the Developing Brain
In 2007, the question of how fluoride affects the developing brain gained renewed attention from researchers around the world. Research teams from Brazil, China, India, Italy, Mexico, and the United States conducted important new analyses, including 3 new studies investigating fluoride's impact on childhood IQ (1a,b,c), and several new animal studies investigating fluoride's effects on learning, memory, and behaviour (1d,e). The studies, which strengthen the concerns expressed by the US National Research Council in 2006, further highlight that it's not just the teeth, but the brain, that may be impacted by too much fluoride during infancy and childhood. As noted in a review presented this fall by Harvard scientists Philippe Grandjean and Anna Choi:
"In humans, only five substances have so far been documented as developmental neurotoxicants: lead, methylmercury, polychlorinated biphenyls, arsenic, and toluene. From this evidence, including our own studies on some of these substances, parallels may be drawn that suggest that fluoride could well belong to the same class of toxicants, but uncertainties remain" (1f). While uncertainties remain -- as is common in science -- several of the studies published this year made important advances in addressing some of the shortcomings of previous research. In particular, a study (1a) linking high-fluoride (5 ppm) water to reduced IQ among a group of Mexican children made important steps in the right direction by simultaneously controlling (via multiple regression analysis) for other key factors known to affect IQ, including parent's education, income, and childhood lead exposure. In addition to controlling for these factors the Mexican researchers helped eliminate a source of bias by "blinding" the psychologist conducting the IQ tests so that the examiner did not know which children had, or did not have, high fluoride exposures.

According to the authors:
"We found that exposure to F (fluoride) in urine was associated with reduced Performance, Verbal, and Full IQ scores before and after adjusting for confounders. The same pattern was observed for models with F in water as the exposure variable.... The individual effect of F in urine indicated that for each mg increase of F in urine a decrease of 1.7 points in Full IQ might be expected."

In addition to assessing the effect of fluoride on IQ, the Mexican team studied the effect of arsenic as well and found similar results. Based on their data, the authors conclude that
"fluoride and arsenic in drinking water have a potential neurotoxic effect in children. It is urgent that public health measures to reduce exposure levels be implemented. Millions of people around the world are exposed to these pollutants and are therefore potentially at risk for negative impact on intelligence. This risk may be increased where other factors affecting central nervous system development, such as malnutrition and poverty, are also present. The risk is particularly acute for children, whose brains are particularly sensitive to environmental toxins. Furthermore, it would be advisable to re-examine the benefits of fluoride given the documented health risks."

While some pro-fluoride supporters may attempt to dismiss the results of this study -- since the levels of fluoride in the water (~5-6 ppm) are higher than the levels added to water in fluoridation programs (0.7-1.2 ppm) -- it would be short-sighted to dismiss such important findings on this basis. After all, the study was able to detect a statistically significant effect within a rather small (n=155) group of children. Since individuals vary widely in their sensitivity to chemicals, it is plausible, and indeed likely, that -- if fluoride can cause IQ loss at 5 ppm in a small group of children (e.g. hundreds) -- it could also cause IQ loss at lower levels in a much larger group of children (e.g. many millions).

Moreover, as noted by Dr. Kathleen Thiessen, a panelist from the National Research Council's review of fluoride, there is "almost certainly overlaps" in the daily doses ingested by some of the Mexican children in the study and the daily doses ingested by some American children - especially when considering the myriad other sources of fluoride exposure now available in the US.


1a) Rocha-Amador D, et al. (2007). Decreased intelligence in children and exposure to fluoride and arsenic in drinking water. Cadernos de Saude Publica 23(Suppl 4):S579-87.
1b) Wang SX, et al. (2007). Arsenic and fluoride exposure in drinking water: children's IQ and growth in Shanyin county, Shanxi province, China. Environmental Health Perspectives 115(4):643-7.
1c) Trivedi MH, et al. (2007). Effect of high fluoride water on intelligence of school children in India. Fluoride 40(3):178-183.
1d) Bera I, et al. (2007). Neurofunctional effects of developmental sodium fluoride exposure in rats. European Review for Medical and Pharmacological Sciences 11(4):211-24.
1e) Chioca LR, et al. (2007). Subchronic fluoride intake induces impairment in habituation and active avoidance tasks in rats. European Journal of Pharmacology Oct 25; [Epub ahead of print]
1f) Choi A, Grandjean P. (2007). Potentials for developmental fluoride neurotoxicity. XXVII Conference of the International Society for Fluoride Research, October 9-12, 2007, Beijing, China.

No comments: