Yes, it keeps your smile healthy, but excess fluoride in your tap water may actually lead to tooth decay and even bone fractures, according to a new report from the National Academy of Sciences.
Researchers reviewed more than 1,200 studies and found that these effects can occur at the current maximum safety limit (4 milligrams of fluoride per liter of water) set by the EPA. There's no reason to panic, though. "The majority of Americans' tap water is safely within recommended levels [0.7-1.2mg per liter]," says committee chairman John Doull, M.D., Ph.D. of the University of Kansas Medical Center. Check out the fluoride count in your area with your local water treatment authority. The American Waterworks Association (awwa.org) has links to state water utilities.