The Centers for Disease Control and Prevention has long recommended putting fluoride in Americans’ drinking water, hailing it as one of the 10 great public health achievements of the 20th century and citing data that the practice reduces cavities by about 25 percent in children and adults.

“Decades of research and practical experience indicate that fluoride is safe and beneficial to oral health,” Linda Edgar, president of the American Dental Association, said in a statement in August.

The Trump campaign declined to comment on Kennedy’s pledge on fluoride.

“While President Trump has received a variety of policy ideas, he is focused on Tuesday’s election,” spokeswoman Danielle Alvarez said in a statement.

Vice President Kamala Harris’s campaign did not immediately respond to a request for comment.

The practice of putting fluoride in Americans’ water began in 1945 in Grand Rapids, Michigan. More than 200 million Americans are on fluoridated water systems, according to a 2022 CDC summary.

In 1962, the U.S. Public Health Service recommended adding small amounts of fluoride, a naturally occurring mineral, to drinking water to strengthen teeth and replace minerals lost to routine wear and tear — a decision that helped fuel wild, often baseless allegations about public health officials’ motivations. That resistance was lampooned in the 1964 satirical film, “Dr. Strangelove,” in which the film’s antagonist — a paranoid general — justifies his decision to spark nuclear war by blaming fluoridation, saying it is “the most monstrously conceived and dangerous Communist plot we have ever had to face.”

But it has long been a bipartisan priority on Capitol Hill and around the country.

Sens. Dick Durbin (D-Illinois) and Roger Marshall (R-Kansas) introduced legislation in January to further fund the CDC’s oral health agenda, including state fluoridation efforts.

Alabama Gov. Kay Ivey (R) endorsed fluoride in April as part of her declaration of a statewide “drinking water week.”

“When communities invest in community water fluoridation, there is an average estimated return on investment of $20 in dental treatment costs for every one dollar in most cities,” Ivey wrote in a proclamation.

Some researchers have raised concerns about fluoride’s effects, such as whether the mineral has a harmful effect on developing brains. A study led by researchers at the University of Southern California and published in JAMA Network Open in May suggested that fluoride exposure during pregnancy was linked to an increased risk of childhood neurobehavioral problems.

“[M]ore studies are urgently needed to understand and mitigate the impacts in the entire U.S. population,” Tracy Bastain, a USC associate professor and author of the study, said in a statement in May. Bastain did not immediately respond to a request for comment about Kennedy’s comments.

Other researchers have dismissed the USC study, and public health officials have frequently played down worries about fluoridation of water, saying that some Americans wrongly believe in myths and conspiracy theories about its risks.

Some local lawmakers and communities around the country continue to push back against the practice of putting fluoride in water, and anti-fluoride activists have turned to the courts. In September, a federal judge ordered the Environmental Protection Agency to further regulate fluoride in drinking water, saying there was potential risk to children’s developing brains. The judge noted that his finding “does not conclude with certainty that fluoridated water is injurious to public health.”

Kennedy, who is skeptical of vaccines, pledged to remove fluoride from drinking water as part of his long-shot independent campaign for president. Kennedy suspended his campaign in August and endorsed Trump, becoming one of his top surrogates on the campaign trail.

The Washington Post reported on Thursday that Kennedy is poised to take a major role overseeing food and health agencies in a possible Trump administration, potentially as a White House czar.

Trump has said he is committed to including Kennedy in his administration and will empower him on public health.

“I said focus on health, you can do whatever you want,” Trump told podcaster Joe Rogan last month, reiterating his pledge when speaking to supporters in New York City two days later.

“I’m gonna let him go wild on health. I’m gonna let him go wild on the food. I’m gonna let him go wild on medicines,” Trump said.