Skip to main content

According to NPR, a new study published in the Journal of American Medical Association found that drinking fluoridated water during pregnancy is linked to a lower IQ in their babies. Because fluoride naturally protects teeth and fights cavities, it is often put in water supplies.

Associate professor of psychology at York University in Toronto Christine Till said, "It's important that decisions about safety need to be based on evidence.” To find such evidence about pregnant women and their babies. Till and her fellow researchers focused on over 500 women and their babies in six cities in Canada.

"It turned out that about half of the sample were cities, like Toronto, where they add fluoride to drinking water," she says, "and the other half, like Montreal and Vancouver, were cities where they do not add fluoride to drinking water."

The researchers measured the amount of fluoride in women’s urine samples and calculated fluoride consumption.

The group found that higher levels of fluoride were correlated with lower IQs in kids.

"Only boys were affected when we looked at urinary fluoride," she says, "but both boys and girls were affected when we looked at maternal fluoride intake or water fluoride concentration."

"We would feel an impact of this magnitude at a population level," Till says, "because you would have millions of more children falling in the range of intellectual disability, or an IQ of under 70, and that many fewer kids in the gifted range."

The Canadian government and the U.S. National Institute of Environmental Health Science funded the study.

"It's actually very similar to the effect size that's seen with childhood exposure to lead," said David Bellinger, a neurology professor at Harvard Medical School and Boston Children's Hospital.

Still, Bellinger cautions not to put too much importance on a single study. He emphasizes that women get most of their fluoride from sources other than water even in cities where the water had fluoride in it. For example, food, tea, and toothpaste are larger sources.

"I think people are going to be shocked but I think people should realize that science is constantly evolving," study author Till says.

Read the full story here.