RFK Jr. wants Trump to remove fluoride from water despite health claims. That’s what the science says.

Fluoridated drinking water is considered one of the Top 10 Public Health Achievements 20th century by the Centers for Disease Control and Prevention (CDC).

Now he’s being called Robert F. Kennedy Jr.— may be on his way to becoming the head of health initiatives in the new presidential administration — a practice that should be stopped. He recently stated that Donald Trump will push to remove fluoride from drinking water on his first day in office.

Over the weekend Trump told NBC News he did not discuss the matter with Kennedy, saying, “But it seems acceptable to me. You know it’s possible.

Kennedy spoke with NPR Wednesday morning. celebrating morning edition“We don’t need fluoride in our water. This is a very bad way to implement it into our systems.”

Below is a brief description of fluoride in drinking water, the history of its controversy, and what the science says.

What is fluoride?

Fluoride is the chemical ion of the mineral fluoride. It is present in nature in trace amounts, according to CDCin soil, water, plants and some food sources, including plants and animals. It can also be released from volcanic emissions or as a byproduct of the production of aluminum, fertilizers and iron ore.

Once it enters the body, according to National Institutes of Health Office of Dietary Supplementsapproximately 80% of what enters the body is absorbed into gastrointestinal tract tract, with about 50% retained in the adult body (all but 1% is stored in bones and teeth), and the remaining 50% is excreted in the urine. In young children, up to 80% of the absorbed fluoride is retained, since more is absorbed into the bones and teeth than in adults.

Why is fluoride found in drinking water?

Fluoride is used to prevent or reverse tooth decay and stimulate new bone formation, according to the National Institutes of Health.

In 1945 Grand Rapids, Michigan. became the first city Drinking water is fluoridated around the world. This came after a doctor conducted research on fluoride and fluorosis (discoloration of tooth enamel due to excess fluoride) and suggested that safe levels could serve to prevent tooth decay.

Fluoridation of Grand Rapids was a 15-year project, according to National Institute of Dental and Craniofacial Researchwhile researchers track the rate of tooth decay among 30,000 schoolchildren; after 11 years, it was found that tooth decay rates among Grand Rapids children 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.

Since 1962, the U.S. Public Health Service has recommended adding fluoride to tap water to reduce the risk and severity of tooth decay, according to the National Institutes of Health. Currently CDC Notesthe recommended concentration, which is not enforceable and is a local rather than federal decision, is 0.7 mg/L. The Centers for Disease Control and Prevention says drinking fluoridated water keeps teeth strong and reduces tooth decay by about 25% in children and adults. (Another common source of fluoride is toothpaste, which, when you brush, attaches fluoride to the surface of your teeth, according to to the Centers for Disease Control and Preventionand increases the amount of fluoride in saliva, which helps restore the outer layer of enamel.)

Today, fluoridated municipal drinking water, including tap water and food and beverages prepared with municipal drinking water, accounts for approximately 60% of fluoride consumption in the United States. CDC notesMore than 209 million people, or 72.3% of the US population served by public water systems, had access to water containing fluoride, which prevents tooth decay.

Chemicals used to fluoridate drinking water in the US, according to NFSare fluorosilicic acid, sodium fluorosilicate and sodium fluoride, which are by-products of production phosphate fertilizer.

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

Is fluoride safe in drinking water?

Yes, says the Centers for Disease Control and Prevention (CDC), which released statement on the safety and effectiveness of fluoridated water earlier this year.

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

Why is fluoride content in tap water controversial?

I posted in my comment until X November 2Kennedy wrote: “Fluoride is an industrial waste linked to arthritis, broken bones, bone cancer, loss of IQ, neurodevelopmental disorders and thyroid disease.”

While he may be correct about the source, the CDC in a recent statement disputes the health risks Kennedy cites, noting that the only potential risk is fluorosis from excess fluoride over a long period of time.

“Teams of experts, consisting of scientists from the United States and other countries with expertise in a variety of medical and scientific disciplines,” it noted, “reviewed the available evidence in the peer-reviewed literature and found no convincing scientific evidence linking community water fluoridation to any potential adverse health effects or systemic disorders, 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’s not to say that adding fluoride to water hasn’t been controversial over the years, dating back to the late 1940s when far-right activists in American politics argued that fluoridation was part of a far-reaching conspiracy to establish a socialist or communist regime.

More recently, in 2016, Harvard Public Health Article has questioned the safety of fluoridated drinking water, which raises the possibility of brain toxicity, based on studies in laboratory animals and other studies linking it to learning, memory and cognitive impairment.

The story prompted a flurry of letters, some supportive, including from a dentist, researcher and former director of preventive dentistry at the University of Toronto who worked for years on comprehensive scientific review fluoride toxicity. He marked“I was trained in conventional dentistry and for many years adhered to the prevailing opinion of the Canadian and US dental/medical establishments that water fluoridation was ‘safe and effective’… I was wrong.”

But many more responses were sharply critical of the article. like one from a group of dental professionals, including the dean of the Harvard School of Dental Medicine, asking for the article to be retracted and providing pages and pages of evidence showing where the article went wrong.

According to downHigh doses of fluoride – usually as a result of rare accidents with excessively high levels of fluoridated water or accidental ingestion of topical fluoride dental products – can lead to nausea, vomiting, abdominal pain, diarrhea, periostitis and even, in rare cases, death. But such an acute dose, the NIH notes, “would be virtually impossible to obtain with water or toothpaste containing standard levels of added fluoride.”

Another possible result of chronic excess fluoride intake is skeletal fluorosis, which can lead to symptoms such as joint pain, osteoporosis and muscle wasting. But in the United States, the phenomenon is “extremely rare,” the National Institutes of Health notes, and there is no evidence that it is caused by recommended levels of fluoride in tap water.

Additionally, the National Institutes of Health adds, while one study found an association between higher maternal urinary fluoride concentrations during pregnancy and higher rates of child neurobehavioral problems at age 3, another similar study found no such association.

As for the claim that higher fluoride intake early in development is associated with lower IQ and other cognitive impairment, the National Institutes of Health adds, researchers, including those behind the National Academies of Sciences, Engineering and Medicine review, say the evidence is weak and methodologically flawed.

Finally, regarding the claims about fluoride and bone cancer, American Cancer Society (ACS) indicates that many systematic reviews of this association have found “inadequate” findings and “no clear association.” It notes that some of the controversy about the possible link stems from an old (1990) study of laboratory animals that found higher-than-expected rates of osteosarcoma – a rare bone cancer – in male laboratory rats drinking fluoridated water.

Meanwhile, many population-based studies have examined the potential link between water fluoride levels and cancer and “have not found a strong association with cancer,” the ACS reports.

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This story was originally published on Fortune.com