Now it is being cited by Robert F. Kennedy Jr. – possibly on his way to becoming head of health initiatives for the next presidential administration – as a practice that should be stopped. He recently claimed that Donald Trump would push to remove fluoride from drinking water on his first day in office.

Over the weekend, Trump told NBC News that he had not discussed the issue with Kennedy, saying “but it sounds good to me. You know it’s possible.”

On Wednesday morning, Kennedy spoke to NPR and noted on Morning Edition: “We don’t need fluoride in our water. It is a very bad way to process it in our systems.”

Below is an introduction to fluoride in drinking water, the history of controversies and what the science says.

What is fluoride?

Fluoride is the chemical ion of the mineral fluorine. According to the CDC, it is naturally present in trace amounts in soil, water, plants and some food sources, including plants and animals. It can also be released from volcanic emissions or as a byproduct of aluminum, fertilizer and iron ore production.

Once in the body, according to the National Institutes of Health Office of Dietary Supplements, about 80% of what is ingested is absorbed in the gastrointestinal tract, with about 50% retained in the body of adults – all but 1% stored in bones and organs. teeth – and the remaining 50% is excreted through the urine. In young children, up to 80% of absorbed fluoride is retained, as more is absorbed by bones and teeth than in adults.

Why is fluoride in drinking water?

According to the NIH, fluoride serves to prevent or reverse tooth decay and stimulate new bone formation.

In 1945, Grand Rapids, Michigan became the first city in the world to fluoridate its drinking water. This came after a doctor’s research into fluoride and fluorosis – the discoloration of tooth enamel due to excess fluoride – and his suspicion that safe levels could serve to prevent tooth decay.

According to the National Institute of Dental and Craniofacial Research, fluoridation in Grand Rapids became a 15-year project during which researchers tracked the rate of tooth decay among 30,000 schoolchildren; after 11 years, it was found that the rate of cavities among children in Grand Rapids born after fluoride was added to the water supply had dropped by more than 60%. It was considered a scientific breakthrough that could revolutionize dental care.

According to the NIH, the U.S. Public Health Service has recommended the addition of fluoride to tap water since 1962 to reduce the risk and severity of tooth decay. Currently, the CDC notes that the recommended concentration – which is not enforceable and is a decision made at the local, not federal, level – is 0.7 mg/L. The CDC says drinking fluoridated water keeps teeth strong and reduces cavities in children and adults by about 25%. (Another common source of fluoride is toothpaste, which, according to the CDC, when you brush with it, sticks fluoride to the tooth surface and increases the amount of fluoride in saliva, which helps rebuild the outer layer of enamel.)

Today, fluoridated municipal drinking water – including tap water and foods and beverages made with municipal drinking water – accounts for approximately 60% of fluoride intake in the US. In 2022, the CDC notes, that will be more than 209 million people, or 72.3% of the US. population served by public water supplies had access to water with a fluoride content that prevents tooth decay.

The chemicals used to fluoridate drinking water in the United States, according to the NSF, are fluorosilicic acid, sodium fluorosilicate and sodium fluoride, which are byproducts of phosphate fertilizer production.

The CDC has a web page that lists fluoride levels in tap water by county.

Is fluoride in drinking water safe?

Yes, says the CDC, which published a statement earlier this year on the safety and efficacy of fluoridated water.

It noted: “The safety and benefits of fluoride have been well documented and extensively reviewed by several scientific and public health organizations. The US Public Health Service; the UK National Institute for Health Research, Center for Reviews and Dissemination, at the University of York; and the National Health and Medical Research Council, Australia, have all conducted scientific reviews by expert panels and concluded that water fluoridation in the community is a safe and effective way to promote good oral health and prevent decay. The U.S. Community Preventive Services Task Force, based on systematic reviews of scientific literature, issued a strong recommendation for community water fluoridation to prevent and control tooth decay in 2001 and again in 2013.”

Why is fluoride in tap water controversial?

In his comments to

While he may be right about the source, the CDC in its recent statement disputes the health risks raised by Kennedy, noting that the only potential risk is fluorosis from too much fluoride over a long period of time.

“Expert panels composed of scientists from the United States and other countries, with expertise in various health and scientific disciplines,” it noted, “considered the available evidence in peer-reviewed literature and found no convincing scientific evidence that water fluoridation in the community in associated with any possible adverse health effect or systemic condition such as an increased risk of cancer, Down syndrome, heart disease, osteoporosis and bone fractures, immune disorders, low intelligence, kidney disease, Alzheimer’s disease or allergic reactions.”

That doesn’t mean the addition of fluoride to water has been controversial all these years — starting in the late 1940s, when far-right activists in American politics alleged that fluoridation was part of a far-reaching plot to implement socialist policies. to lay. or communist regime.

More recently, in 2016, a Harvard Public Health article questioned the safety of fluoridated drinking water, raising the possibilities of brain toxicity, based on laboratory animal studies and other studies linking it to learning, memory and cognitive deficits.

That story prompted a flood of letters, some supportive, including from the dentist, researcher and former head of preventive dentistry at the University of Toronto, who spent years working on a comprehensive scientific study of fluoride toxicity. He noted: “I was trained in traditional dentistry and for many years have accepted the prevailing view of the dental/medical community in Canada and the US that water fluoridation is ‘safe and effective’… I was wrong.”

But many more comments were fiercely critical of the article, such as one from a group of dental professionals, including the dean of the Harvard School of Dental Medicine, who asked for it to be retracted and provided pages of evidence about where the article went wrong. .

According to the NIH, high doses of fluoride — usually the result of rare accidents involving excessive levels of fluoridated water or the accidental ingestion of fluoride dental products intended for topical use — can result in nausea, vomiting, abdominal pain, diarrhea, periostitis, and even , rarely, dead. But such an acute dose, the NIH notes, “would be virtually impossible to achieve with water or toothpaste containing standard levels of added fluoride.”

Another possible result of chronic, excessive fluoride ingestion is skeletal fluorosis, which can lead to symptoms from joint pain to osteoporosis and muscle wasting. But it is “extremely rare” in the US, the NIH notes, and there is no evidence that it is caused by the recommended fluoride levels in tap water.

Furthermore, the NIH adds, while one study found a link between higher fluoride concentrations in the mother’s urine during pregnancy and higher rates of neurobehavioral problems in a three-year-old child, another similar study found no such link .

Regarding the claim that higher fluoride intakes during early development are associated with lower IQ and other cognitive impairments, the NIH adds, researchers, including those behind a National Academies of Sciences, Engineering, and Medicine review, consider it evidence as weak and methodologically flawed.

Finally, regarding fluoride and bone cancer claims, the American Cancer Society (ACS) points out that many systematic reviews of the association have found “inadequate” conclusions and “no clear association.” It notes that some of the controversy over the possible link stems from an old (1990) study in laboratory animals, which found higher rates of osteosarcoma – a rare bone cancer – in male laboratory rats that drank fluoridated water.

Many population studies have now looked at the possible link between water fluoride levels and cancer and “have not found a strong link with cancer,” the ACS reports.

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