WASHINGTON — Robert F. Kennedy Jr. said Saturday that a Trump administration would, on its first day, “advise all U.S​. water systems to remove fluoride from public water.”

Kennedy linked fluoride to various illnesses, despite major medical associations supporting water fluoridation, which they say is safe anda benefit to public health.

“President ​@realDonaldTrump and First Lady @MELANIATRUMP want to Make America Healthy Again,” the former Democratic presidential hopeful wrote in a post to X, tagging Michael Connett, an attorney who has led litigation that opposes the fluoridation of public drinking water.

Kennedy, a vaccine skeptic who has a history of pushing conspiracy theories, is primed to play a key role in a future Trump administration’s health policy. Since dropping out of the presidential race and endorsing Trump, Kennedy has frequently appeared on the campaign stumping for the former president, and Trump said at a rally this week that if he is elected, Kennedy is “going to work on health and women’s health.”

Trump has embraced Kennedy. At an event in Arizona earlier this week, the former president said that Kennedy “can do anything he wants” in a potential Trump administration.

“He really wants to with the pesticides and the, you know, all the different things. I said, ‘He can do it. He can do anything he wants.’ He wants to look at the vaccines. He wants — everything. I think it’s great. I think it’s great,” Trump said.

In late October, Trump said that having Kennedy as an ally “is such a great honor.”

“I’m going to let him go wild on health. I’m going to let him go wild on the food. I’m going to let him go wild on medicines,” Trump said at that event.

Kennedy, a former independent presidential candidate, has touted widely debunked theories linking vaccines and autism. He also previously said that he would support a national ban on abortion after three months of pregnancy, before quickly walking back his comments.

When reached for comment on Kennedy’s proposal, Trump campaign senior adviser Danielle Alvarez did not commit to backing the plan.

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

Major public health groups such as the American Dental Association, the American Academy of Pediatrics and the Centers for Disease Control and Prevention support water fluoridation, citing studies showing that the mineral helps fight cavities. Health groups also emphasize that the practice is safe.

“Water fluoridation is an equitable and inexpensive way to ensure that prevention of dental disease reaches everyone in a community,” the American Academy of Pediatrics’ website says.

The academy’s Campaign for Dental Health also says on its website that “there is no scientifically valid evidence to show that fluoride causes cancer, kidney disease, or other disorders.”

Fluoride helps make teeth “stronger and more resistant to decay,” according to the CDC’s website, and drinking fluoridated water “reduces cavities by about 25% in children and adults.”

“Documented risks of community water fluoridation are limited to dental fluorosis, a change in dental enamel that is cosmetic in its most common form. Changes range from barely visible lacy white markings in milder cases to pitting of the teeth in the rare, severe form,” the CDC’s website says, noting that most dental fluorosis seen in the U.S. today is “of the mildest form.”

Similarly, the American Dental Association says on its website that water fluoridation is “safe and effective.”

“Throughout more than 70 years of research and practical experience, the overwhelming weight of credible scientific evidence has consistently indicated that fluoridation of community water supplies is safe,” says a fact sheet on the association’s website.

Water fluoridation is not ubiquitous, and the CDC does not mandate fluoridation programs. Some cities have worked to end public water fluoridation programs as groups argue that it should be up to them to decide whether they want fluoride in public water supplies.