Can fluoride impact brain development?

Although previous reports suggest that high levels of fluoride may harm reproductive health and fertility, a 2022 Canadian study found that fluoride exposure during pregnancy was not associated with fertility issues or negative birth outcomes.

Moreover, studies examining the potential links between fluoride exposure and neurodevelopmental issues and low IQ in children have produced conflicting results.

For example, research published in 2016 found that IQ levels among children were negatively correlated with fluoride levels in drinking water. The study’s authors suggested a need to develop solutions for preventing the potentially harmful effects of excessive fluoride intake.

In addition, a 2019 study published in JAMA Pediatrics found that exposure to fluoride during pregnancy may negatively affect a child’s intellectual development. According to the study’s authors, the findings suggest reducing fluoride intake during pregnancy might be warranted.

However, Professor Oliver Jones, FRSC, FRACI, AFIChemE, an Associate Dean of the Biosciences and Food Technology Discipline at RMIT University in Australia, tells Healthnews that the JAMA Pediatrics study had several flaws and limitations.

“For a start, the claimed effect was only seen in boys and not girls, whose IQ apparently went up slightly with fluoride exposure,” Jones says. “But the average [IQ] change was not statistically significant in any case.”

Moreover, a 2023 meta-analysis showed that fluoride exposure related to community water fluoridation is not associated with lower IQ scores in children. However, the researchers suggest that higher fluoride levels occurring in some areas require further investigation.

Jones explains that the first rule in toxicology, or the study of poisons, is that the dose makes the poison.

“Everything is toxic at a specific level, even water,” Jones says. “Fluoride is a natural compound that is found in a wide range of waters and the environment. The levels added to drinking water are well below those needed to induce any toxicological effect.”

Unpublished fluoride data raises questions

Robert F. Kennedy Jr., environmental lawyer, activist, and 2024 presidential candidate, tells Healthnews the NTP’s unpublished report shows the data supports a consistent inverse association between fluoride exposure and children’s IQ.

“In the meta-analysis by NTP, 52 of 55 studies revealed a decrease in children’s IQ with an increase in fluoride,” Kennedy says. “Internal emails discovered through [the Freedom of Information Act] have shown that this extremely alarming report by NTP was hidden from the public by Assistant Health Sec. Rachel Levine.”

According to a Science report, the emails, which were released to the Fluoride Action Network (FAN), showed that in 2022, a senior official at the Department of Health and Human Services intervened to stop the publication of the NTP report days before it was scheduled to be released.

However, Healthnews cannot confirm allegations that Assistant Health Secretary Rachel Levine deliberately delayed the report’s release, as attempts to reach out to Levine for comment have been unsuccessful.

Moving forward, Kennedy says a review of the heads of regulatory agencies is needed, and those with a history of protecting corrupt corporations over the public good need to be replaced with top scientists in each field who have shown a dedication to scientific integrity throughout their careers.

Regardless of the court’s ruling on the health impacts of fluoride, Kennedy says, “Though I have spent my career using the court of law to draw attention to this type of corporate corruption, I will not rely on court decisions but rather on peer-reviewed science to make recommendations to the public.”

Jones says the idea that water companies or the government would add something to the water they knew was poisonous makes no logical sense.

“The CEOs, etc, and [their] families have to drink the water as well,” Jones explains. “So, why would they poison themselves, and even if the motivation was just profit, then it makes no economic sense to purposely poison your customer base.”

Known health effects of high fluoride levels

The EPA limits the amount of fluoride in drinking water to 4 milligrams per liter of water (mg/L). The agency imposes that limit to prevent health problems associated with high levels of the mineral, including skeletal fluorosis — a condition characterized by joint pain and tenderness — and tooth discoloration or pitting in children.

This standard differs from the recommended optimal level of 0.7 milligrams per liter set by the PHS. The agency established that level to help prevent tooth decay while minimizing the risk of dental fluorosis.

The EPA says that, based on the data, it is likely that some children 8 years and younger are exposed to too much fluoride while their teeth are forming due to their high fluid intake relative to their body weight and because of high levels of fluoride occurring naturally in their local drinking water.

“While I gather that there are cases of fluoride toxicity occurring in the U.S. annually, most of these are due to accidental ingestion of fluoridated toothpastes and/or mouthwashes (which you aren’t meant to swallow) not from water, and even most of these cases are non-symptomatic,” Jones adds. “I don’t think we need to be worried about fluoride added to drinking water.”