A study of young children in Canada suggests those whose mothers drank fluoridated tap water while pregnant had slightly lower IQ scores than children whose mothers lived in non-fluoridated cities. But don’t dash for the nearest bottled water yet. Health experts at the American Academy of Pediatrics and the American Dental Association cautioned that public policy and drinking water consumption should not change on the basis of this study.
The American Academy of Pediatrics, likewise, recommends fluoride in toothpastes and tooth varnishes for children because the mineral prevents tooth decay. In drinking water, “fluoridation has been incredibly protective,” said Aparna Bole, a pediatrician who chairs the Council on Environmental Health at the American Academy of Pediatrics. Fluoridation reduces the prevalence of cavities by about one-fourth, according to the Centers for Disease Control and Prevention. The CDC considers water fluoridation one of the 10 top health achievements of the past century, on par with vaccines and antismoking campaigns.
Dozens of cities in the United States and Canada, such as Portland, Ore., and Vancouver, do not add fluoride to city water. Elsewhere in the United States, fluoridation is the norm. As of 2014, per CDC data, two-thirds of people in the United States had fluoride in their drinking water. In 2015, to reduce the risk of mild fluorosis, the Department of Health and Human Services cut its fluoride recommendations almost in half, from 1.2 milligrams per liter to 0.7 milligrams per liter.
The researchers compared the fluoride intake of 400 women, some who lived in fluoridated cities and some who did not. They controlled for factors such as household income and the women’s education. A 1 milligram daily increase in fluoride intake was associated with a 3.7-point drop in children’s IQ, they found.