New study finds U.S. fluoride exposure linked to better adolescent cognitive performance 

ADA endorses community water fluoridation as safe, beneficial to oral health 

A newly published national study of U.S. adolescents reports that childhood exposure to fluoride at levels typical of community water fluoridation is associated with modestly better cognitive performance in secondary school, with no evidence of harm to cognitive functioning in later adulthood. Published Nov. 19, the findings position water fluoridation, a public health measure the ADA has long endorsed, as a safe and effective way to prevent tooth decay. 

The study, “Childhood fluoride exposure and cognition across the life course,” analyzed data from the nationally representative High School and Beyond cohort—26,820 students from more than 1,000 U.S. high schools—and examined fluoride exposure from conception through adolescence. The authors emphasized that most past research has focused on fluoride levels in countries such as China, India, and Iran which are far higher than those found in U.S. community water systems. 

The researchers noted that although their observational study cannot definitively establish causality, their results align with broader literature showing no adverse cognitive effects of community water fluoridation.  

“Our results provide strong evidence that exposure to fluoride—at levels ordinarily seen in the United States and of relevance to policy debates about municipal water fluoridation—has benefits for adolescent cognition and is, at worst, not harmful for later-life cognitive functioning,” the authors concluded.

In their summary of existing research, the authors said fluoride levels typical of community water fluoridation are not linked to lower IQ scores in children. The new study extends this work by directly examining long-term U.S. data and fluoride exposures “within the range typical in most places and of greatest relevance to policy debates about government water fluoridation.” 

"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,” the authors wrote.  

Children exposed to recommended levels of fluoride in drinking water exhibit “modestly better” cognition in secondary school, according to the study. While the cognitive advantage was not statistically significant at around age 60, the point estimates remained positive. 

This study follows a 2024 report from the National Toxicology Program that found fluoride in drinking water at more than twice the recommended concentration in the U.S. is associated with reduced IQ in children. The latest Science Advances study, in contrast, focuses on fluoride concentrations commonly encountered through U.S. community water fluoridation programs, which currently recommend 0.7 mg/L. 

“Our results cast doubt on the assertion that exposure to recommended levels of fluoride reduce academic achievement or cognitive functioning,” the authors wrote. 

The authors highlight several methodological strengths: the use of nationally representative data, exposure levels aligned with U.S. public health recommendations, adjustment for key confounders, and the assessment of cognition both in adolescence and in late adulthood. 

Community water fluoridation has long been recognized as a cornerstone of oral health prevention, with the Centers for Disease Control and Prevention naming it one of the 10 great public health interventions of the 20th century.  

David Savitz, Ph.D., professor of epidemiology, pediatrics, and obstetrics and gynecology at Brown University, said in an accompanying Science Advances editorial that researchers determined through statistical and attributional analyses that children experienced no negative effects—and slightly better cognition—from drinking fluoridated water.  

“Until clear evidence exists that water fluoridation lacks public health benefit or compelling evidence of harm at the level of fluoride exposure in fluoridated water, neither of which has occurred, it seems foolhardy to interfere with a long-established and well-recognized public health success,” he wrote.  

ADA News will continue to follow research developments related to community water fluoridation and public health.