The pits.
Fluoride prevents cavities, but too much can damage teeth
SIN
WASHINGTON, DC -. Protecting the Environment Agency (EPA) should decrease the maximum amount of fluoride, it allows in drinking water, according to a National Academies report Sciences (NAS) released today. NAS group found compelling evidence of serious tooth decay in 10% of children exposed to the maximum legal limit - about 4 times higher than what is usually added to drinking water. Most of the group also found that adults exposed to these levels over a lifetime were likely to have a higher incidence of bone fractures.
Water suppliers have added fluoride to drinking water in the United States since the 1950s to fight against dental cavities. In 1962, the US Public Health Service has recommended a concentration of 0.7 to 1.2 parts per million (ppm), depending on the amount of water people in an area normally drink. Ironically, children who consume too much fluoride in their first 8 years of life may develop lasting problems with their teeth, including pitting of the enamel and tooth decay. Excess fluoride also weakens bones for decades. In addition, some studies have shown that fluoride causes cancer in laboratory animals.
In 1986, the EPA has set the maximum contaminant level for fluoride at 4 ppm. Seven years later, a NAS group agree with this standard, pending further research on uncertainties regarding exposure and toxicity. But the new panel, chaired by toxicologist John Doull of the University of Kansas Medical Center in Kansas City, came to a different conclusion.
Part of the reason is that the panelists a more refined look at the state of the tooth called enamel fluorosis. Previously, most researchers considered fluorosis an aesthetic problem rather than a health problem. But when the panel considered the most serious consequences - bites, bacterial contamination, and loss of the tooth - 10 of the 12 members decided that they were recorded as adverse health effects. And when panelist Charles Poole, an epidemiologist at the University of North Carolina, Chapel Hill, traced the prevalence of dental fluorosis in 94 studies, it was found that the prevalence dropped to near zero when fluoride levels in water were below 2 ppm. This and other evidence is sufficient to warrant a new standard, said Poole.
This is not to say that all questions concerning the health effects are set. The Panel found that the evidence of the effects of cancer is "tentative and mixed", but noted that a large enough study to be released this summer should help establish future research objectives. In addition, monitoring is required on preliminary results of endocrine effects in animals and IQ deficits in Chinese populations.
braces the report, which was 3 years in the making, is winning. "It is very comprehensive" says toxicologist Tim Kropp of the Environmental Working group, an advocacy group in Washington, DC
Related Sites
- CDC report on water fluoridation drinking
- review in 1991 of the public health Service of the benefits and risks of fluoridation
- fluoride Action Network, a group concerned about the toxicity and health impacts
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