US agency tightens recommended fluoride levels

The US Department of Health and Human Services’ (HHS) new recommendation on community water fluoridation lowers the optimal threshold of the mineral in drinking water to prevent tooth decay. The agency’s final recommendation endorses a single level of 0.7 milligrams of fluoride per litre of water, which updates and replaces the previous recommended range of 0.7 to 1.2 milligrams per litre that was issued in 1962.

The change is recommended because Americans now have access to more sources of fluoride, such as toothpaste and mouth rinses, than were available when water fluoridation was first introduced in the US, HHS explained. This increased exposure has caused a jump in fluorosis, which typically manifests as barely visible lacy white marking or spots on the tooth enamel, the agency said.

HHS expects that its new recommended level will maintain the protective decay prevention benefits of water fluoridation and also reduce the occurrence of dental fluorosis. Because the natural levels of fluoride in most water systems are often too low to prevent tooth decay, HHS says the practice of adding fluoride to a community’s water system has grown steadily. Nearly 75% of Americans who are served by public water systems receive fluoridated water, according to the agency.