Mind and Mouth: The Hidden Brain Benefits of Fluoridated Drinking Water

Recent research challenges long-standing concerns that fluoride in drinking water adversely affects cognition. In a major longitudinal study titled “Childhood fluoride exposure and cognition across the life course”, investigators used data from the nationally representative U.S. “High School and Beyond” cohort, tracking participants from adolescence into their early 60s. Those children who grew up consuming water at recommended fluoride levels scored modestly higher on 12th-grade tests of mathematics, reading, and vocabulary than peers who had lower or no fluoride exposure.¹ The cognitive benefit, though small (about 7% of a standard deviation), was consistent across all tested domains.

At approximately age 60, analysis of global cognitive function — based on memory, attention, and fluency measures — showed no adverse effect linked to early-life fluoride exposure.

These findings reference a long history of water fluoridation for dental public health. The first deliberate community-water fluoridation effort began in 1945 in Grand Rapids, Michigan, where adding fluoride to the water supply led to substantial reductions in dental decay in children.² Over decades, fluoridation contributed to profound declines in cavity rates among both children and adults.³

The new study’s results counter claims often based on older research from areas with very high natural fluoride levels that fluoride impairs intelligence. A prominent meta-analysis incorporating 74 studies had found an overall inverse association between fluoride exposure and IQ scores in children.⁴ However, as noted by the authors of the new U.S. cohort study, the majority of those older studies involved fluoride concentrations well above those typical in U.S. water supplies (often > 1.5 mg/L), whereas current recommended levels in the U.S. are 0.7 mg/L.

Accordingly, fluoride exposure at standard community-water levels appears not only safe but modestly associated with better academic performance in adolescence and not linked to impaired cognition in later adulthood.⁵

Given this robust evidence supporting both oral health and cognitive safety, public health arguments for community water fluoridation, long recognized as one of the major public-health achievements of the 20^th century, are strengthened.

References:

1. Warren JR, Rumore G, Kim S, Grodsky E, Muller C, Manly JJ, Brickman AM. Childhood fluoride exposure and cognition across the life course. Sci Adv. 2025 Nov 21;11(47):eadz0757. doi: 10.1126/sciadv.adz0757. Epub 2025 Nov 19. PMID: 41259530; PMCID: PMC12629170.
   
   
2. www.nidcr.nih.gov/health-info/fluoride/the-story-of-fluoridation
   
   
3. Burt BA. Fifty years of water fluoridation. Br Dent J. 1995 Jan 21;178(2):49-50. doi: 10.1038/sj.bdj.4808645. PMID: 7848748.
   
   
4. Taylor KW, Eftim SE, Sibrizzi CA, et al. Fluoride Exposure and Children’s IQ Scores: A Systematic Review and Meta-Analysis. JAMA Pediatr. 2025;179(3):282–292. doi:10.1001/jamapediatrics.2024.5542
   
   
5. David A. Savitz Evidence-based water fluoridation policy.Sci. Adv.11,eaed4503(2025). DOI:10.1126/sciadv.aed4503