New Research Suggests Fluoride in Drinking Water May Boost Cognitive Performance:

The long-standing practice of adding fluoride to public drinking water is facing renewed scrutiny in the United States, with debates centering on whether its benefits outweigh potential risks. Recent research, however, is challenging claims that fluoride exposure harms children’s cognitive development and even suggests it could have positive effects. Concerns escalated earlier this year after a government study from the National Toxicology Program (NTP) linked high levels of fluoride exposure to lower IQ in children. Critics of water fluoridation, including U.S. Department of Health and Human Services Secretary Robert F. Kennedy Jr., have cited this research in calls to end the practice. Utah and Florida have already banned adding fluoride to public water systems. Yet, experts caution that the NTP study examined fluoride exposure at levels at least twice the federally recommended limits, leaving insufficient data to assess the effects of standard fluoridation. Responding to this gap, a new study published Wednesday in Science Advances looked at typical, recommended fluoride levels in drinking water. Researchers found “robust evidence” that children exposed to fluoride performed better on cognitive tests compared to peers without such exposure. Dr. Rob Warren, lead author and sociology professor at the University of Minnesota, said the findings surprised him. “I was shocked by the NTP results and motivated to provide research more relevant to public policy decisions,” he said. He emphasized that the earlier study’s high-dose comparisons were like testing a heart medication at a million milligrams instead of the recommended dose—results that aren’t applicable to real-world situations. Warren’s team followed a cohort of nearly 27,000 people tracked since their high school years in the 1980s. By combining historical data on community water fluoridation from the U.S. Department of Health and Human Services and the U.S. Geological Survey with participants’ performance on math, reading, and vocabulary tests, the researchers could evaluate the long-term cognitive impact of fluoride exposure. The study grouped participants based on childhood exposure: consistently exposed to recommended fluoride levels, never exposed, or partially exposed due to changes in local water policies. Results showed that students partially exposed to fluoride scored higher than those with no exposure, while lifelong exposure correlated with the highest test scores. Follow-up assessments into participants’ 60s suggested fluoride did not contribute to cognitive decline later in life. While cognitive tests do not measure IQ directly, Warren notes they strongly correlate with intelligence and reflect a combination of cognitive ability and educational opportunity. He is conducting further research to directly examine fluoride’s effect on IQ and track participants’ exact childhood residences. Fluoride, naturally found in some foods and groundwater, strengthens tooth enamel and helps prevent decay. Decades of research indicate that removing fluoride from public water could result in millions of additional cavities in children and billions in dental costs. Experts also note that dental pain from cavities can affect school attendance and focus, potentially influencing cognitive outcomes. The American Dental Association and the Centers for Disease Control and Prevention continue to support water fluoridation. The CDC recommends an optimal level of 0.7 milligrams of fluoride per liter of water, though communities are not required to implement it. Recently, the U.S. Food and Drug Administration restricted prescription fluoride supplements, citing safety concerns and effects on the gut microbiome. Dr. Bruce Lanphear, an epidemiologist at Simon Fraser University, emphasized the importance of strong evidence for population-wide interventions like fluoridation. “Population strategies can have enormous health impacts, but only if their safety and effectiveness are rigorously demonstrated,” he said. Dr. David Savitz of Brown University countered that, given the long-standing success of water fluoridation, the burden of proof lies with those seeking to end it. “Until clear evidence shows harm or lack of benefit at recommended levels, it seems foolhardy to interfere with a public health practice that works,” he wrote. For now, this new research adds nuance to the debate, suggesting that fluoride at recommended levels may support not only oral health but also cognitive performance, reinforcing the argument for continuing the decades-long public health practice.

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