President-elect Donald Trump's pick to run the nation's health agency, Robert F. Kennedy Jr., has railed against the practice of adding fluoride to drinking water, a measure that public health experts and dentists credit with reductions in tooth decay. Seven out of 10 Americans who get their drinking water from public water systems receive fluoridated water, according to data from the Centers for Disease Control and Prevention.

Shortly before the election, Kennedy wrote in a post on X that "the Trump White House will advise all U.S. water systems to remove fluoride from public water" on Inauguration Day. His post also repeated debunked claims that the mineral increases the risk of bone cancer.

Though Kennedy promised that the new administration would warn against fluoridation on its first day, realities of governance may slow any action.