Exposure to fluoride may lower children's intelligence says a study pre-published in Environmental Health Perspectives, a publication of the National Institute of Environmental Health Sciences (online December 17, 2010).
Fluoride is added to 70% of U.S. public drinking water supplies.
According to Paul Connett, Ph.D., director of the Fluoride Action Network, "This is the 24th study that has found this association, but this study is stronger than the rest because the authors have controlled for key confounding variables and in addition to correlating lowered IQ with levels of fluoride in the water, the authors found a correlation between lowered IQ and fluoride levels in children's blood. This brings us closer to a cause and effect relationship between fluoride exposure and brain damage in children."
"What is also striking is that the levels of the fluoride in the community where the lowered IQs were recorded were lower than the EPA's so-called 'safe' drinking water standard for fluoride of 4 ppm and far too close for comfort to the levels used in artificial fluoridation programs (0.7 – 1.2 ppm)," says Connett.
In this study, 512 children aged 8-13 years in two Chinese villages were studied and tested – Wamaio with an average of 2.47 mg/L water fluoride (range 0.57-4.50 mg/L) and Xinhuai averaging 0.36 mg/L (range 0.18-0.76 mg/L).
The authors eliminated both lead exposure and iodine deficiency as possible causes for the lowered IQs. They also excluded any children who had a history of brain disease or head injury and none drank brick tea, known to contain high fluoride levels. Neither village is exposed to fluoride pollution from burning coal or other industrial sources.
About 28% of the children in the low-fluoride area scored as bright, normal or higher intelligence compared to only 8% in the "high" fluoride area of Wamaio.
In the high-fluoride city, 15% had scores indicating mental retardation and only 6% in the low-fluoride city.
The study authors write: "In this study we found a significant dose-response relation between fluoride level in serum and children's IQ."
In addition to this study, and the 23 other IQ studies, there have been over 100 animal studies linking fluoride to brain damage (all the IQ and animal brain studies are listed in Appendix 1 in The Case Against Fluoride available online at
http://fluoridealert.org/caseagainstflu ... dices.html).
One of the earliest animal studies of fluoride's impact on the brain was published in the U.S. This study by Mullenix et. al (1995) led to the firing of the lead author by the Forsyth Dental Center. "This sent a clear message to other researchers in the U.S. that it was not good for their careers to look into the health effects of fluoride – particularly on the brain," says Connett.
Connett adds, "The result is that while the issue of fluoride's impact on IQ is being aggressively pursued around the world, practically no work has been done in the U.S. or other fluoridating countries to repeat their findings. Sadly, health agencies in fluoridated countries seem to be more intent on protecting the fluoridation program than protecting children's brains."
When the National Research Council of the National Academies reviewed this topic in their 507-page report "Fluoride in Drinking Water: A Review of EPA's Standards" published in 2006, only 5 of the 24 IQ studies were available in English. Even so the panel found the link between fluoride exposure and lowered IQ both consistent and "plausible."
According to Tara Blank, Ph.D., the Science and Health Officer for the Fluoride Action Network, "This should be the study that finally ends water fluoridation. Millions of American children are being exposed unnecessarily to this neurotoxin on a daily basis. Who in their right minds would risk lowering their child's intelligence in order to reduce a small amount of tooth decay, for which the evidence is very weak." (see The Case Against Fluoride, Chelsea Green, October 2010)
