A recent report from the US government has determined, with moderate confidence, a link between children consuming higher-than-recommended levels of fluoride and lower IQ.
The addition of low levels of fluoride to drinking water has long been recognized as a major public health accomplishment by the US Centers for Disease Control. The presence of fluoride helps to strengthen teeth and prevent cavities.
The World Health Organization (WHO) has recommended a safe fluoride level of 1.5 mg/L in drinking water, which is higher than the federal health officials' recommended fluoridation level of 0.7 mg per liter of water.
The US Public Health Service recommends a fluoride concentration that is half the amount considered safe by the WHO. Several international epidemiological studies conducted in Canada, China, India, Iran, Pakistan, and Mexico on pregnant women, infants, and children exposed to fluoride levels over 1.5 mg per liter of drinking water revealed lower IQs. The authors propose additional research to better understand the potential risks linked to low levels of fluoride exposure.
The US has accumulated 50 years of data demonstrating the positive effects of fluoride. Often, the issue with these foreign research papers is that they exhibit significant bias. The sample sizes are yet another concern. The locations are different, as the foreign studies can't relate to American circumstances. Too much chlorine can represent a real problem, and it has in some cases. Nevertheless, there are numerous safeguards in the water systems to prevent excessive quantities of fluoride.