Fluoride at twice recommended limit linked to lower IQ in kids: U.S. report
"This report is crucial for our understanding of the risks," said Ashley Malin, a researcher at the University of Florida who has studied the impact of higher fluoride levels on pregnant women and their children. She described it as the most rigorously conducted study of its kind.
The long-awaited report, released Wednesday by the National Toxicology Program, part of the Department of Health and Human Services, reviews studies from Canada, China, India, Iran, Pakistan, and Mexico. The report concludes that drinking water with more than 1.5 milligrams of fluoride per liter is consistently associated with lower IQs in children.
While the report does not quantify the exact IQ loss at varying levels of fluoride exposure, some of the studies reviewed suggest a decrease of 2 to 5 IQ points in children with higher fluoride exposure.
Since 2015, federal health officials have recommended a fluoridation level of 0.7 milligrams per liter of water. For five decades before that, the recommended upper limit was 1.2 milligrams. The World Health Organization has set a safe limit for fluoride in drinking water at 1.5 milligrams per liter.
The report notes that approximately 0.6% of the U.S. population—around 1.9 million people—are on water systems with naturally occurring fluoride levels of 1.5 milligrams or higher.
"The findings from this report raise important questions about how to protect these people and what the best approach is," Malin said.
The 324-page report does not reach a conclusion about the risks associated with lower levels of fluoride, calling for further study. It also does not address the potential effects of high fluoride levels on adults.
The American Dental Association, a strong proponent of water fluoridation, had previously criticized earlier versions of the analysis and Malin's research. When asked for comment, a spokeswoman said the organization's experts were still reviewing the report.
