Countries that do not fluoridate their water have also seen big drops in the rate of cavities.Since the mid-1940s, compounds containing the mineral fluoride have been added to community water supplies throughout the U.S. to prevent tooth decay. Health concerns expressed by opponents have largely been dismissed until recently. Now, evidence is mounting that in an era of fluoridated toothpastes and other consumer products that boost dental health, the potential risks from consuming fluoridated water may outweigh the benefits for some individuals. Last summer, for the first time in 53 years, the U.S. Public Health Service lowered its recommended levels of fluoride in drinking water.
Countries with fluoridated water
Source: OECD.Stat/Dental Health
Countries without fluoridated water
Perhaps most worrisome is preliminary research in laboratory animals suggesting that high levels of fluoride may be toxic to brain and nerve cells. And human epidemiological studies have identified possible links to learning, memory, and cognition deficits, though most of these studies have focused on populations with fluoride exposures higher than those typically provided by U.S. water supplies.
“First, since dental cavities have decreased in countries both with and without water fluoridation, we need to make sure we are dosing our water with the proper amount of fluoride for dental medicine purposes, but no more.
“Third, we need to find out if there are populations highly vulnerable to fluoride in drinking water—bottle-fed infants whose formula is made with tap water, for example, or patients undergoing dialysis. If these individuals are at risk, their water must come from a source that is lower in fluoride.”
*This description of the Cochrane Collaboration’s findings in relation to water fluoridation and adult cavities is a clarification of the text in the print edition of the Spring 2016 Harvard Public Health, where this article originally appeared.