In a remarkable turnabout, federal health officials say many Americans are getting too much fluoride, and it's causing splotches on children's teeth and perhaps other, more serious problems.
The U.S. Department of Health and Human Services announced plans Friday to lower the recommended level of fluoride in drinking water for the first time in nearly 50 years, based on a fresh review of the science.
The announcement is likely to renew the battle over fluoridation, even though the addition of fluoride to drinking water is considered one of the greatest public health successes of the 20th century. The U.S. prevalence of decay in at least one tooth among teens has declined from about 90 percent to 60 percent.
"Like anything else, you can have too much of a good thing," said Dr. Howard Pollick, a professor at the University of California, San Francisco's dental school and spokesman for the American Dental Association.
One reason behind the change: About 2 out of 5 adolescents have tooth streaking or spottiness because of too much fluoride, a government study found recently.
But there are also growing worries about more serious dangers from fluoride.
The Environmental Protection Agency released two new reviews of research on fluoride Friday. One of the studies found that prolonged, high intake of fluoride can increase the risk of brittle bones, fractures and crippling bone abnormalities.
Critics of fluoridated water seized on the proposed change Friday to renew their attacks on it -- a battle that dates back to at least the Cold War 1950s.
"Anybody who was anti-fluoride was considered crazy," said Deborah Catrow, who successfully fought a ballot proposal in 2005 that would have added fluoride to drinking water in Springfield, Ohio. The fluoridated water standard since 1962 has been a range of 0.7 parts per million for warmer climates where people used to drink more water to 1.2 parts per million in cooler regions. The new proposal from HHS would set the recommended level at just 0.7.