Claims suggesting NIH declared that fluoride in water 'reduces the IQ of children' are misleading

On Nov. 2, former independent presidential candidate Robert F. Kennedy Jr. claimed in an X post that Donald Trump would push to remove fluoride from drinking water on his first day in office if elected president.

“On January 20, the Trump White House will advise all U.S. water systems to remove fluoride from public water,” Kennedy wrote alongside a variety of claims about alleged negative health effects of fluoride, including “IQ loss” and “neurodevelopmental disorders.”

Fluoride strengthens teeth and reduces cavities by replacing minerals lost during normal wear and tear, according to the U.S. Centers for Disease Control and Prevention.

The addition of low levels of fluoride to drinking water has long been considered one of the greatest public health achievements of the last century, the CDC says. But some people believe adding fluoride to drinking water is “misguided, ineffective and risky,” Joe Schwarcz, Ph.D., explained in an article titled “The Fluoride Controversy” for McGill University’s Office for Science and Society.

In October, nearly a month before Kennedy’s announcement, viral posts on X claimed that the National Institutes of Health (NIH) “finally admitted” that fluoride in drinking water “reduces the IQ of children” in a recent report.

“The government put fluoride in our water and attacked anyone who questioned it. Now — the NIH (after major pressure) has declared it ‘reduces the IQ of children.’ This is under-covered news,” one post with roughly 3 million views said.

Multiple VERIFY readers, including Melanie and Mike, sent us messages asking if the viral claims are true.

THE QUESTION

Did NIH declare that fluoride in drinking water reduces the IQ of children?

THE SOURCES

• A report published by the National Toxicology Program, a part of the U.S. Department of Health and Human Services’ National Institutes of Health (NIH)
• U.S. Centers for Disease Control and Prevention
• U.S. Environmental Protection Agency
• American Dental Association
• California Dental Association
• American Academy of Pediatrics
• Donald L. Chi, DDS, Ph.D., board-certified pediatric dentist, health services researcher, professor of Oral Health Sciences and associate dean for research at the University of Washington School of Dentistry 
• Chelsea Fosse, D.M.D., director of the Research and Policy Center at the American Academy of Pediatric Dentistry (AAPD) 
• Ashley Malin, Ph.D., assistant professor in the Department of Epidemiology at the University of Florida

THE ANSWER

Claims suggesting NIH declared that fluoride in drinking water reduces the IQ of children are misleading and take a recent report’s findings out of context.

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WHAT WE FOUND

A recent report from the National Toxicology Program, a part of the National Institutes of Health, determined “with moderate confidence” that there is a link between higher levels of fluoride exposure and lower IQ in kids.

But the report does not say that the current recommended level of fluoride in drinking water in the United States, which is 0.7 milligrams per liter of water, “reduces the IQ of children,” like viral social media posts suggest.

The 324-page report, which was published in August, found that drinking water containing more than twice the recommended amount of fluoride in the U.S. is consistently associated with lower IQs in children in 10 countries, including Mexico and Canada. But the National Toxicology Program notes that none of the studies evaluating IQ in its report were conducted in the U.S.

In 1950, federal public health officials endorsed community water fluoridation to prevent tooth decay, and continued to promote it even after fluoride toothpaste brands hit the market several years later. Though fluoride can come from many sources, drinking water is the main source for Americans, researchers say.

Officials lowered their recommendation for drinking water fluoride levels in 2015 to 0.7 mg/L to address a tooth condition called fluorosis, which can cause splotches on teeth and was becoming more common in young children in the U.S.

“While dental fluorosis can be moderate or severe, causing extensive enamel changes, in the U.S., dental fluorosis is mostly mild and cosmetic meaning it does not affect tooth function and is not painful,” the CDC says.

In 2016, the National Toxicology Program started a systematic review of previously published research evaluating the extent and quality of the evidence linking fluoride exposure to neurodevelopmental and cognitive effects in humans. The report was designed to evaluate total fluoride exposure from all sources, but the agency says it was not conducted to evaluate the health effects of fluoridated drinking water alone.

The report evaluated 72 studies on the association between fluoride exposure and IQ in children. The determination about lower IQs in children was based primarily on studies conducted in 10 non-U.S. countries, such as Canada, China, India, Iran, Pakistan and Mexico, where some pregnant women, infants and children received total fluoride exposure amounts higher than 1.5 mg/L of drinking water. These fluoride exposures came from many sources, including drinking water, prepared beverages, foods and dental products.

The National Toxicology Program notes in its report that no studies evaluating IQ were conducted in the U.S. However, the report did find that about 0.6% of the U.S. population, or about 1.9 million people, are on water systems with naturally occurring fluoride levels of 1.5 mg/L or higher, according to the CDC.

The CDC says it does not have a comprehensive list of the natural or adjusted fluoridation levels of every state’s water systems because states voluntarily provide this information at varying frequencies. The agency recommends contacting your local utility provider to find out the exact fluoridated water level in your community.

The report did not try to quantify exactly how many IQ points might be lost at different levels of fluoride exposure. However, some of the studies that were reviewed suggested IQ was 2 to 5 points lower in children who had higher fluoride exposures. The report also did not reach a conclusion about the risks of lower levels of fluoride, saying more research is needed to determine this, nor did it answer what high levels of fluoride might do to adults.

“I think this (report) is crucial in our understanding” of this risk, Ashley Malin, a University of Florida researcher who has studied the effect of higher fluoride levels in pregnant women on their children, told the Associated Press in August. She called it the most rigorously conducted report of its kind.

A few days after the report was published, the American Dental Association (ADA), which had previously been critical of earlier versions of the report, said that it “continues to endorse community water fluoridation as safe and beneficial to oral health.”

“The bottom line is that the National Toxicology Program report and other recent systematic reviews indicate that the level of fluoride used in community water fluoridation is effective for preventing tooth decay and is not associated with any change in people’s IQ or neurological development,” said Scott Tomar, D.M.D., a member of the National Fluoridation Advisory Committee, the ADA’s standing panel of experts that provide ongoing advice about the safety and effectiveness of fluoride.

The American Academy of Pediatric Dentistry (AAPD) also “affirms that consuming fluoridated drinking water is both safe and effective in preventing and controlling dental caries [cavities],” according to Chelsea Fosse, D.M.D., director of the AAPD’s Research and Policy Center.

“More than 65 years of research makes water fluoridation one of the most widely studied public health measures in history. Sound scientific evidence proves fluoridation at the recommended levels to be safe and effective for reducing tooth decay in both children and adults, without any evidence of negatively impacting IQ levels,” Fosse said.

However, some critics of community water fluoridation, like the Fluoride Action Network, praised the report’s findings.

“This is a historic day for those who have warned about fluoridation’s obvious risks for more than 75 years,” Stuart Cooper, the director of the Fluoride Action Network, which works to end water fluoridation, said in a press release issued after the report came out.

“This report, along with the large body of published science, makes it abundantly clear that the question isn’t whether fluoridation is safe, but instead how many children have been needlessly harmed,” Cooper added.

When asked if parents should be worried about the report’s findings, Donald L. Chi, DDS, Ph.D., a pediatric dentist, researcher and professor at the University of Washington said, “No, I don’t think parents should be concerned.”

“As parents, our role is to be concerned on behalf of our kids. That being said, I think a lot of those concerns can be directed toward other things out there, and not fluoride,” Chi told VERIFY. “Fluoride is heavily regulated in the U.S. At point seven parts per million, which is the current recommendation, water fluoridation is safe for kids.”

Fosse says that pediatric dentists and their teams “regularly work with parents and caregivers to optimize total fluoride exposures for children in a way that maximizes remineralization (cavity prevention) and minimizes the potential for any negative effects.”

“Look to your child’s pediatric dentist for partnership in determining the best care approach for your child, whether that be in regard to water fluoridation, topical treatments, or other measures supporting optimal oral health,” Fosse said.

In late September, a federal judge cited the report’s findings in ordering the U.S. Environmental Protection Agency (EPA) to further regulate fluoride in drinking water.

U.S. District Judge Edward Chen cautioned that while it’s uncertain whether the amount of fluoride typically added to water is causing lower IQ in kids, he determined that mounting research suggests an unreasonable risk. He ordered the EPA to take steps to lower that risk but didn’t specify how the agency should go about doing so.

It’s the first time a federal judge has made a determination about the neurodevelopmental risks to children of the recommended U.S. water fluoride level, according to Malin, who called it “the most historic ruling in the U.S. fluoridation debate that we’ve ever seen.”

The Associated Press contributed to this report.