Fluoride’s Surprising Benefits: New Research Challenges Claims About Drinking Water Risks

Recent research has cast a positive light on fluoride in drinking water, challenging previous concerns about its impact on cognitive function. This groundbreaking study, published in the journal Science Advances, presents evidence that exposure to low-level fluoride—at the US-recommended concentration of 0.7 milligrams per liter—may actually improve cognitive test performance in young people rather than harm it. The findings come as a direct response to a 2024 report from the National Toxicology Program which had determined with “moderate confidence” that higher fluoride levels were associated with lower IQ scores. That earlier report caused significant concern, despite primarily focusing on countries with fluoride levels far exceeding US safety standards. Dr. Rob Warren, lead author of the new study and sociology professor at the University of Minnesota, explained his motivation to CNN: “I wouldn’t have done this work had it not been an empirical question that I didn’t think we had an answer to, of great immediate policy interest.” He criticized the previous research as misleading, likening it to testing a drug at massively higher doses than recommended and drawing conclusions about normal usage.

The comprehensive new study examined nearly 27,000 people, tracking both their cognitive performance and exposure to fluoridated community drinking water. The results were striking: students exposed to fluoride for part of their childhood demonstrated higher high school test scores compared to those with no exposure. Even more impressive, those with consistent fluoride exposure throughout childhood showed the most significant cognitive benefits. The researchers didn’t stop there—they conducted follow-up testing through 2021 among participants aged 60 or older and found no association between fluoride exposure and cognitive decline in aging populations. While cognitive tests are not direct measures of IQ, Warren noted there is a strong correlation, as these assessments evaluate mental functioning, reasoning, problem-solving, and memory. Warren is now working on research that will directly evaluate the relationship between fluoride exposure and IQ specifically, to provide even more definitive evidence.

This research comes at a critical time, as more than 170 communities across the United States have removed fluoride from their drinking water since 2010. Public figures like Health and Human Services Secretary Robert F. Kennedy Jr. have criticized fluoride as “industrial waste,” claiming it harms brain development, bone health, and causes other health issues. Earlier this year, Utah and Florida became the first states to ban the addition of fluoride to public drinking water, with similar antifluoridation bills introduced in North Dakota, Tennessee, and Montana. These policy shifts stand in stark contrast to the science-based recommendation from public health experts, who have long supported community water fluoridation as one of the most effective public health measures for preventing tooth decay.

Fluoride has a long and successful history in American public health. The naturally occurring mineral, found in soil, water, plants, and many foods, was first added to US drinking water in Grand Rapids, Michigan, in 1945 specifically to combat tooth decay. The results were remarkable—after just ten years, local dentists reported a 60% reduction in cavities among children. This dramatic improvement in dental health led to the widespread adoption of community water fluoridation across the country, eventually becoming recognized as one of the ten greatest public health achievements of the 20th century by the Centers for Disease Control and Prevention. The practice has been endorsed by major health organizations worldwide, including the World Health Organization, the American Dental Association, and the American Academy of Pediatrics.

The potential consequences of removing fluoride from public water systems are substantial. Research published earlier this year estimated that eliminating fluoride from US public water would result in 25.4 million additional decayed teeth in children and adolescents within just five years. This increase in dental problems would bring an estimated $9.8 billion in additional healthcare costs. While the new study didn’t directly measure dental health outcomes, experts point out that tooth decay and dental pain often cause children to struggle with concentration and miss school, potentially affecting their cognitive test performance. The connection between oral health and overall wellbeing, including cognitive development, highlights the multifaceted benefits of community water fluoridation.

The debate over fluoride exemplifies the challenge of public health policy in an era of misinformation. Despite the overwhelming scientific consensus supporting water fluoridation at recommended levels, public skepticism persists, fueled by misinterpretation of research and concerns about government-mandated health interventions. Dr. Warren’s study provides timely evidence that not only is fluoride at recommended levels safe, but it may offer cognitive benefits beyond dental health. As communities and states consider their policies on water fluoridation, this research offers a crucial perspective: the practice that has been preventing cavities for generations might also be supporting brain development and cognitive function. The findings underscore the importance of evaluating public health measures based on comprehensive, relevant scientific evidence rather than fears or studies of irrelevant exposure levels. In the case of community water fluoridation, the science increasingly suggests we have more to gain than to lose.