USA: A new study published in Science Advances suggests that childhood exposure to fluoride at levels commonly recommended for public water supplies may be linked to slightly better cognitive performance during adolescence—although this advantage appears to fade by midlife.The research was led by John Robert Warren from the Institute for Social Research and Data Innovation at the University of Minnesota, along with colleagues.The study revisits the long-debated question of how everyday fluoride exposure influences brain development and cognition. Unlike earlier research that examined the effects of unusually high fluoride levels, this investigation focused on the typical concentrations used in U.S. municipal water systems—levels central to current debates on the safety and benefits of community water fluoridation.The team analyzed data from the High School and Beyond cohort, a nationally representative sample comprising 58,270 American high school sophomores and seniors surveyed in 1980. Researchers estimated each participant’s fluoride exposure from conception through adolescence by mapping municipal fluoridation records and naturally occurring fluoride concentrations in local water systems.To measure cognitive outcomes, the investigators relied on standardized assessments administered during the participants’ 12th-grade year, evaluating mathematics, reading comprehension, and vocabulary. The study led to the following findings:Follow-up cognitive assessments were conducted more than 40 years later, when participants were approximately 60 years old, to evaluate midlife cognitive functioning.The analysis adjusted for various potential confounders, including socioeconomic status, demographic factors, geographic region, and urbanicity.Adolescents who consumed drinking water with recommended fluoride levels showed modestly better performance across all cognitive tests compared with peers who had minimal or no fluoride exposure.The observed cognitive benefit in adolescence was estimated at around 7% of a standard deviation, indicating a small yet meaningful population-level effect.Both those exposed to fluoride throughout childhood and those exposed for only part of their childhood exhibited comparable cognitive advantages.By age 60, the earlier cognitive gains had largely faded, with only slight, non–statistically significant differences observed between fluoride-exposed and non-exposed groups.These findings suggest that while fluoride exposure in childhood may support better cognitive performance during adolescence, the advantage does not appear to be sustained into later adulthood.The study also addresses concerns arising from past research that reported lower intelligence scores among children exposed to unusually high fluoride concentrations. The authors emphasize that such elevated levels are rarely encountered in the United States and do not reflect the typical exposures assessed in this analysis.“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 researchers wrote.The findings add nuance to the ongoing debate about water fluoridation, suggesting that fluoride at standard public health levels may offer cognitive as well as dental benefits—at least during adolescence.Reference:Warren, J. R., Rumore, G., Kim, S., Grodsky, E., Muller, C., Manly, J. J., & Brickman, A. M. (2025). Childhood fluoride exposure and cognition across the life course. Science Advances. https://doi.org/adz0757