Robert F Kennedy Jr says Donald Trump will push to remove fluoride from drinking water on his first day in office.

Fluoride strengthens teeth and reduces cavities by replacing minerals lost during normal wear and tear, according to the US Centers for Disease Control and Prevention.

The addition of low levels of fluoride to drinking water has long been considered one of the greatest public health achievements of the past century.

Mr Kennedy, a prominent supporter of the rejected public health claims, made the statement on social media platform X alongside a variety of claims about the health effects of fluoride.

“On January 20, the Trump White House will advise all US water systems to remove fluoride from public water,” Kennedy wrote.

Mr. Trump and his wife, Melania Trump, “want to make America healthy again,” he added, repeating a phrase Trump often uses and refers to Mr. Kennedy.

It was not immediately clear whether Mr. Kennedy discussed Saturday’s post with Mr. Trump or his aides.

Neither Mr. Trump’s campaign nor a spokesman for Mr. Kennedy responded to questions Saturday night.

But the sudden and unexpected social media post over the weekend evoked the chaotic policy-making process that has defined Trump’s tenure in the White House, when he will issue policy statements on social media at almost any hour.

It also underscored the concerns many experts have about Mr. Kennedy, who has long promoted debunked theories about vaccine safety that have implications for US public health.

In 1950, federal officials approved water fluoridation to prevent tooth decay and continued to promote it even after fluoride toothpaste brands hit the market a few years later. Although fluoride can come from many sources, drinking water is the main source for Americans, researchers say.

Officials lowered their recommendation for fluoride levels in drinking water in 2015 to address a dental condition called fluorosis, which can stain teeth and had become more common in U.S. children.

In August, a federal agency determined “with moderate confidence” that there is a link between higher levels of fluoride exposure and lower IQ in children.

The National Toxicology Program based its conclusion on studies involving fluoride levels at about twice the recommended limit for drinking water.

A federal judge later cited that study to order the US Environmental Protection Agency to continue regulating fluoride in drinking water.

U.S. District Judge Edward Chen cautioned that he was not certain that the amount of fluoride commonly added to water was causing lower IQs in children, but concluded that growing research indicated an unreasonable risk that it might be.

He ordered the EPA to take steps to reduce that risk, but did not say what those steps should be.

In his X post on Saturday, Mr Kennedy tagged Michael Connett, the lead lawyer representing the plaintiff in that suit, the environmental advocacy group Food & Water Watch.

Mr. Kennedy’s anti-vaccine organization has a lawsuit pending against news organizations including The Associated Press, accusing them of violating antitrust laws by taking steps to identify misinformation, including about Covid-19 and Covid-19 vaccines .

Mr Kennedy is on leave from the group but is listed as one of its lawyers in the suit.

What role Kennedy might have if Trump wins Tuesday remains unclear. Kennedy recently told NewsNation that Trump asked him to “reorganize” agencies, including the US Centers for Disease Control and Prevention, the National Institutes of Health, the Food and Drug Administration and some agencies within the Department of Agriculture.

But for now, the former independent presidential candidate has become one of Trump’s best surrogates.