High concentrations of fluoride that occur naturally in a small minority of the nation's drinking water supplies can damage teeth and bones, and federal regulators should reduce the level that is considered safe for human consumption, a National Academy of Sciences panel said Wednesday.
Source: www.NYTimes.com Panel Urges Lowering of Allowable Fluoride By WARREN E. LEARY
Published: March 23, 2006
WASHINGTON, March 22 — High concentrations of fluoride that occur naturally in a small minority of the nation's drinking water supplies can damage teeth and bones, and federal regulators should reduce the level that is considered safe for human consumption, a National Academy of Sciences panel said Wednesday.
The 12-member panel, which spent almost three years studying the issue at the request of the Environmental Protection Agency, did not address the health effects of the much smaller amounts of fluoride added to the drinking water of 160 million Americans to prevent tooth decay.
Instead, its report dealt with the 200,000 people whose water supplies have at least four parts per million of naturally occurring fluoride, the environmental agency's current maximum.
"Our committee concluded unanimously that E.P.A. should lower the maximum contaminant level goal for fluoride," said John Doull, the committee chairman, a retired professor of pharmacology and toxicology at the University of Kansas.
A majority of the committee, Mr. Doull said, concluded that water fluoride concentrations at or near the current standard caused adverse health effects.
In a statement, the environmental agency responded that it would seriously consider the conclusions of the study, but that any changes in the standard would have to await a complete review of all data.
The Environmental Working Group, a nonprofit watchdog organization that has long advocated limiting fluoride in drinking water, praised the report as raising health concerns. It said in a statement that the study "puts concerns about safety of fluoride in tap water squarely in the mainstream of scientific thought."
A vast majority of Americans consume water containing 0.7 to 1.2 parts of fluoride per million, well below the limits set by environmental and health authorities, the study said.
But about 10 million people live in areas where the drinking water contains naturally occurring fluoride. Besides the 200,000 whose levels are four parts per million or higher, 1.4 million more are drinking water with two parts per million, a so-called secondary limit set by the E.P.A. to protect against cosmetic dental discoloration and other effects.
The communities that have high levels of natural fluoride are widely scattered around the nation, the report said. Because the problem has been well reported over the years, many of the people affected are already drinking bottled water or using commercially available filters to reduce the fluoride to safer levels.
The study panel included experts in dental health, disease tracking, chemicals and risk assessment.
The report said that most exposure to fluoride came from consuming water and water-based beverages, but that dental products, food and other sources also contributed. Highly exposed populations include individuals who have high concentrations of fluoride in their drinking water or who drink more water than average because of exercise, outdoor work or a medical condition.
Relative to body weight, infants and young children are exposed to three to four times as much fluoride as adults. Fluoride also accumulates in bone over time, so groups likely to have increased bone fluoride concentrations include the elderly.
The study said overexposure to fluoride put children at risk of developing severe enamel fluorosis, characterized by enamel loss on teeth, pitting and discoloration, which occurs before teeth erupt in the mouth. About 10 percent of children in communities with water fluoride levels at or near the current limit develop this severe condition, which results in permanent tooth damage, it said.
While most panel members concluded that this severe enamel loss should be classified as an adverse health effect, Dr. Doull said 2 of the 12 members felt there was not enough evidence to classify it as more than a cosmetic problem. But he added that all concurred with the recommendation that the maximum allowable level of fluoride should be lowered to prevent the condition.
Several studies indicate an increased risk of bone fracture in populations exposed to fluoride concentrations in water at or near the limit, the committee said. Although fluoride increases bone density as it accumulates, there is evidence that under certain conditions it can weaken bones and increase the risk of fractures, it said.