Nationwide Study Challenges Fears Of Fluoride's Cognitive Risks
New research is challenging previous hesitations about fluoride in drinking water. Adding fluoride to drinking water has been a longstanding practice in the U.S.
In May of 2025, Utah became the first state to ban fluoride in public drinking water, with legislators acknowledging the potential benefits but maintaining it is an issue of “personal choice.”
Researchers analyzed data from roughly 26,820 individuals in the national High School and Beyond cohort, matching participants’ childhood fluoride exposure (from conception through adolescence) with their high school test scores in math, reading, and vocabulary. The study found that those who drank water with recommended fluoride levels performed modestly better on these cognitive measures than peers without similar exposure.
“We find robust evidence that young people who are exposed to typical, recommended levels of fluoride in drinking water perform better on tests of mathematics, reading, and vocabulary achievement in secondary school than their peers who were never exposed to sufficient levels of fluoride,” said the authors of the study.
This research challenges earlier claims made by U.S. Secretary of Health Robert F. Kennedy, Jr., that fluoride in tap water would harm cognition.
While this is an observational study and cannot definitively establish causality, the findings run contrary to some earlier research suggesting neurodevelopmental harm.
Dental and public health experts welcomed the findings. The American Dental Association noted that the research supports longstanding community water fluoridation policies, describing fluoride at these levels as “safe and effective.”
Nevertheless, there is still a need for further research. While the improved test scores are encouraging, there could be other factors contributing to the differences. The debate around fluoride safety will continue, as some U.S. states move to ban or restrict fluoridation.