Fluoride study triggers renewed debate on IQ scores

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

- 

Published in the prestigious Journal of the American Medical Association (Jama) Pediatrics, it has sparked pushback from some scientists who criticize 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 Jr, 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 reviewed 74 studies on fluoride exposure and children's IQ conducted in 10 countries, including Canada, China and India.