A government study linked high fluoride exposure to lower IQs in kids. Why was it kept hidden?

A government study that shows a link between childhood exposure to fluoride and lower intelligence was allegedly blocked from public release by federal officials for two years.

A lawsuit filed against the Environmental Protection Agency (EPA) by the Fluoride Action Network, a nonprofit dedicated to educating on the issues of fluoride and community water fluoridation, argues that Rachel Levine, assistant secretary for health for the U.S. Department of Health and Human Services (HHS), blocked the report from public release in 2022 following pressure from the Centers for Disease Control and Prevention (CDC) and the dental lobby.

A spokesperson for the EPA declined to comment. Fast Company also reached out to the HHS and CDC.

Last week, the HHS released that report from the HHS’s National Toxicology Program (NTP), called the Monograph on the State of the Science on Fluoride, which found that data from human studies provides evidence that high fluoride exposures are consistently associated with decreased IQ in children. The NTP review identified 72 epidemiologic studies on the effects of fluoride exposure on children’s IQ. It concluded that fluoride exposure, such as drinking water containing more than 1.5 milligrams of fluoride per liter, is associated with lower IQ in children.

The NTP report was released to the public because of a lawsuit filed by the Fluoride Action Network and other groups against the EPA over the classification of fluoride as a neurotoxin. U.S. District Court Judge Edward M. Chen could make a ruling on the case any day now.

Through a Freedom of Information Act request, the Fluoride Action Network discovered internal documents that showed Levine quashed the public release of the report, the group says. The Fluoride Action Network then subpoenaed the report as evidence in its court case, and Judge Chen subsequently forced the report’s release through a court order.

Is fluoride safe or not? Experts weigh in

Critics say the report largely discredits what the government and the dental industry has said for years: that fluoride is safe. In 1945, cities began putting fluoride in public tap water as a way to improve oral health and reduce cavities. Levels of fluorination vary by state, with the District of Columbia having the highest levels, and Hawaii and New Jersey the lowest.

“The report just flies in the face of what we’ve been told for 75 years,” says Stuart Cooper, the Fluoride Action Network’s executive director. “They’ve staked their medical credibility on it. It’s the lie that’s too big to fail.”

NTP’s director, Rick Woychik, says the NTP report may provide important information to regulatory agencies that set standards for the safe use of fluoride, but it does not, and was not intended to, assess the benefits of fluoride.

The American Dental Association (ADA) defends the practice of fluoridation in water and released a statement asserting that the organization does not believe the new report provides any new or conclusive evidence that should necessitate changes in current fluoridation practices. “Community water fluoridation has been hailed by the Centers for Disease Control as one of the 10 great public health achievements,” Dr. Linda Edgar, president of the ADA, commented in the statement.

Greg Kail, spokesman for the American Water Works Association, says he doesn’t believe that water systems will change course due the NTP review.

“The recommended concentration of fluoride in drinking water is [0.7] parts per million, which is less than half of the level of potential concern in the NTP review,” Kail wrote in an email to Fast Company. “The American Dental Association, Centers for Disease Control and other leading health organizations support community water fluoridation at the right level to achieve the desired public health benefits.”

Cooper says as many as 1,473 local communities have voluntarily ended water fluoridation programs since 2010, with at least 30 to 40 more in just the past few months.

The NTP study began in 2016, and the final study underwent two interagency peer reviews from the National Academies of Science, Engineering and Medicine and experts in several federal health agencies, as well as a third review by a panel of external experts.

“This is a landmark study,” says Ashley Malin, an assistant professor at the University of Florida who has been researching the impact of fluoride exposure for a decade. She says it’s the most rigorously conducted, comprehensive report of its kind, and the first time a government agency has made a determination about fluoride’s potential impact on child IQ.

Malin’s own 2015 research linked higher levels of fluoride to attention-deficit/hyperactivity disorder (ADHD) in children. Subsequent studies found the same. At least 7.1 million children and adolescents in the U.S. were diagnosed with ADHD in 2022, an increase of a million from 2016, according to the CDC.

Malin says the practice of community fluoridation, or adding fluoride to tap water, can also involve other metal exposures. The process typically involves adding sodium fluoride, fluorosilicic acid, or sodium fluorosilicate, which is often a byproduct of phosphate fertilizer production, and research shows that they can contain barium, arsenic and high levels of aluminum, and, when combined with disinfecting agents such as chlorine, they can leach lead from lead-bearing plumbing.

Cooper hopes the report will end controversy over fluoride as a neurotoxin. He says water treatment plants need not invest in major system changes to discontinue community fluoridation; they simply must turn off injection equipment.

“They will save money and stop harming people,” says Cooper. “A cavity can be filled, but damage to the brain is permanent.”