Robert F. Kennedy Jr. speaks during a campaign rally for Republican presidential candidate former President Donald Trump at Macomb Community College on November 1, 2024 in Warren, Michigan. Kennedy has called for an end to fluoride in water supplies, a practice that saves billions each year on dental care.

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It is considered one of the greatest public health achievements of the 20th century: By adding a small amount of fluoride to the water supply, health officials prevented millions of tooth decay, saved tens of billions of dollars in dental costs and made children healthier.

But in a post he subsequently listed several false statements about the effects of fluoride and then linked to a video on a website founded by prominent anti-vaxxer and conspiracy theorist Del Bigtree.

Former President Donald Trump seemed open to the idea of ​​removing fluoride from the water supply. “Well, I haven't talked to him about it yet, but it sounds OK to me,” Trump said in a telephone interview with NBC on Sunday. “You know, it’s possible.”

Experts immediately condemned the promise to remove fluoride from water. “Fluoride has tested well. “It clearly and definitively reduces tooth decay and is not associated with clear evidence of the chronic diseases mentioned in this tweet,” says Dr. Paul Offit, researcher and physician at Children's Hospital of Philadelphia.

“Robert F. Kennedy Jr. is a science denier. He makes up his own scientific truths and ignores the actual truths,” Offit says.

Fluoride has clear benefits

The science is clear: adding fluoride to the water supply has been effective in reducing tooth decay in both children and adults. Fluoride is used to restore minerals in the teeth that are lost when bacteria multiply rapidly in the mouth, especially after eating sugary snacks.

According to the American Dental Association, more than a dozen recent studies from governments and academic institutions around the world have found that fluoride reduces tooth decay in children and adults by about 25%. This is particularly beneficial for lower-income families who may not have access to fluoride-containing products such as toothpastes and mouthwashes. A study from the Colorado School of Public Health found that adding fluoride to water alone saved about $6.8 billion in dental costs in one year.

In recent years, some studies have suggested that high levels of fluoride could lead to lower intelligence quotients in children. A recent government review found moderate evidence of effect, but not at the concentrations currently used in U.S. drinking water. The ADA says the benefits of fluoridation continue to outweigh any potential risks.

Strong contrasts

Dr. Amanda Stroud is a dentist who sees the impact of fluoride – and the lack of it – every day in her work as a dental director at a nonprofit healthcare organization in western North Carolina. AppHealth serves children who have fluoridated city water and others who have well water that does not contain fluoride. The differences are huge, she says.

The children who drink fluoride water often have good, strong teeth without cavities, she says. They may take smiling and pain-free eating for granted, “which is a joyful thing at this age,” says Stroud.

Things look different when children drink well water. “You could potentially have decay in any tooth,” she says. “When they smile, their teeth may erupt all the way to the gum line. Your teeth look brown or stained.”

And this is a painful condition that makes it difficult to brush your teeth and eat healthy foods like fruits and vegetables. “It’s heartbreaking,” she says.

The original public health conspiracy theory

Despite the clear benefits, conspiracy theories surrounding fluoride have been around for almost as long as water has been fluoridated, according to Matthew Dallek, a political historian at George Washington University.

“In some ways, the fluoride in drinking water conspiracy theory is one of the original public health conspiracy theories,” he says.

Fluoride was first introduced in 1945 in Grand Rapids, Michigan, which also happened to be the site of the Trump campaign's final rally before Election Day.

Adding fluoride to water quickly spread across the country when the benefits became apparent in Grand Rapids.

But wild theories about the chemical were circulating right from the start. “It served as a near-perfect conspiracy theory,” he explains. Fluoride was invisible, mandated by the government, and present in tap water, a substance that just about everyone consumed.

Dallek says the theories were promoted in the 1960s in particular by the John Birch Society, a far-right group that claimed communists had infiltrated much of the government. The group believed that “every step toward state intervention was essentially a step toward communist intervention,” he says. As a result, they “used fluoride as part of a communist conspiracy.”

Claims about fluoride were vague, but also included the idea that it was somehow used for mind control or that it was a chemical weapon designed to poison people. At least initially, the ideas seemed to resonate with the public.

“Movements emerged all over the country to stop fluoridation in drinking water,” says Dallek.

In 1966, the Honolulu government vetoed a measure that would add fluoride to water. Fluoride is still not used in Hawaii, and a 2015 report found that the state had the highest childhood tooth decay rate in the nation and continues to have one of the worst oral health outcomes of any state.

Mocked in films

But the movement never caught on more widely. The fluoride conspiracies have been featured in films such as Stanley Kubrick's “Dr. Strangelove,” in which General Jack Ripper starts a nuclear war partly because he believes fluoride is a communist conspiracy. The problem largely disappeared in the 1980s. “There have been occasional anti-fluoride campaigns across the country,” says Dallek.

But in the wake of the COVID-19 pandemic, fluoride conspiracy theories have resurfaced, often promoted by people like Kennedy who also believe childhood vaccinations cause autism and other diseases. Today, anti-vaxxers emphasize the harms of fluoride along with those of vaccines and chemtrails, alleged trails of chemicals left by commercial airliners to harm people and the environment.

Kennedy released a video Monday urging his supporters to vote for Trump so he can be elected with a strong mandate. “Then no one will be able to stop us if they authorize me to eliminate corruption in the federal authorities and especially in our health authorities,” he said.

But Offit says Kennedy's potential role in leading the country's public health could prove disastrous, particularly for young people who benefit from both fluoride and vaccinations. “Only the children will suffer from his ignorance,” Offit says.