Divisive study finds link between fluoride and childhood IQ loss

New report in JAMA Pediatrics combines data from 74 studies on fluoride exposure and children’s IQ

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Adding fluoride to community drinking water is credited with reducing the average number of teeth with cavities. File photo: AFP

Published: 12:42pm, 7 Jan 2025

A controversial new study in a US medical journal could reignite debate over fluoride’s safety in water, linking higher exposure levels to lower IQ in children.

Published on Monday in the prestigious Journal of the American Medical Association (JAMA) Pediatrics, it has sparked pushback from some scientists who criticise the study’s methods, defend the mineral’s proven dental benefits, and warn the findings may not directly apply to typical US water fluoridation levels.

Its release comes as President-elect Donald Trump prepares to take office. His health secretary nominee, Robert F. Kennedy Jnr, is a vocal critic of fluoridated water, which currently serves over 200 million Americans, or nearly two-thirds of the population.

Researchers from the National Institute of Environmental Health Sciences (NIEHS) reviewed 74 studies on fluoride exposure and children’s IQ conducted in 10 countries including Canada, China, and India.

The same scientists helped formulate an official government recommendation in August that there is “moderate confidence” that higher levels of fluoride are linked to lower IQ scores.

Now, the team led by Kyla Taylor told Agence France-Presse the new analysis found a “statistically significant association” between fluoride exposure and reduced IQ scores.