The alarming findings
were released in Environmental Health Perspectives, a publication of the National Institutes of Health
Professor Philippe Grandjean and research scientist Anna L. Choi of Harvard University partnered with medical researchers Guifan Sun and Ying Zhang of China Medical University to conduct the study, which was performed using internal university funds.
The researchers examined data on water fluoridation levels from a variety of medical databases and compared them to IQ scores of children who lived in the associated neighborhoods. One area of focus was data from rural parts of China which have not been publicized so far. In total, 27 separate studies were examined.
"Children in high fluoride areas had significantly lower IQ scores than those who lived in low fluoride areas," the researchers concluded. "The results suggest that fluoride may be a developmental neurotoxicant that affects brain development at exposures much below those that can cause toxicity in adults."
Digital Journal contacted the authors of the study for further insight into the report and its implications.
"We knew from the National Research Council review
that there were studies that suggested neurotoxicity, but we were a bit surprised that 26 of 27 studies
showed poorer performance of children with increased fluoride exposure," Grandjean stated in an email response. "This suggests that we need documentation to determine the dose-response relationship."
While the report acknowledges that the observed decrease in IQ may be relatively small, there is still plenty of cause for concern. "The fluoride ion is very small, so it likely passes the placenta quite easily," Grandjean explained, indicating that fluoride can be transferred from a pregnant mother to her fetus. Thus, the continued usage of fluoridated water from generation to generation may have a greater cumulative effect on human intelligence than any single study could measure.
Will more studies be performed? "Yes, it would be a good idea to carry out research in this field, and China seems well suited for this purpose," Grandjean said.
The report is only the latest university-funded analysis to point out the neurological dangers of fluoridated water.
A fluoride study
released in 2008 by the Nanjing University School of Medicine found "a consistent and strong association between the exposure to fluoride [in water] and low IQ".
In addition, a report published in the Journal of Hazardous Materials
by university and government researchers indicated that even fluoride levels that are below the EPA limit can have negative effects on IQ and neurological health.
Experts like Dr. Hardy Limeback
, the Head of Preventive Dentistry at the University of Toronto, have also warned parents against giving children fluoridated toothpaste or water.
Meanwhile, the city council of Portland, Oregon, just voted unanimously in favor of fluoridating the municipal water supply, even though residents voted down three similar ballot measures in the past, according to the Oregonian
. It appears that documented health concerns and public opposition will not stop some legislatures from deciding what compounds should be added to the water.