Quick Summary
- Study Findings: A new study indicates no significant link between fluoridated water and cognitive performance in children.
- Research Scope: This comprehensive research included nearly 27,000 participants, examining various cognitive tests over time.
- Comparison Basis: Unlike previous studies, this research utilized a nationally representative sample, enhancing its validity.
- Expert Insight: Dr. Rob Warren highlighted the importance of studying recommended fluoride levels compared to toxic doses.
A new study reports no link between fluoridated water and cognitive performance on reading, vocabulary, and math tests. The authors summarized their key finding, writing, “We find that children exposed to recommended levels of fluoride in drinking water exhibit modestly better cognition in secondary school, an advantage that is smaller and no longer statistically significant at age ~60.”
What did the National Toxicology Program report about fluoride?
A 2024 report by the National Toxicology Program (NTP) raised questions about a possible association between fluoride in drinking water and cognitive effects in children. Unfortunately, the NTP report did not include any large-scale study from the United States on fluoride’s non-dental effects from water consumption. The robust new study by Warren et al fills that gap.
This report highlights the need for further research on the cognitive effects of fluoride, especially in contexts where the fluoride levels differ significantly from those in the U.S.
How does this study differ from previous research on fluoride?
The vast majority of studies examining fluoride and cognition have been conducted in China, India, and other nations where the natural levels of fluoride in water are typically much higher than those found in fluoridated water in the U.S. Additionally, many of these studies were based on the scores of only one cognitive/IQ test and analyzed cognitive test scores from fewer than 800 children.
By contrast, the new U.S. study published by Science Advances included nearly 27,000 people and examined multiple test scores at different times of their life, beginning with their high school years. The study also took into account whether or not the people in the study lived in a fluoridated community. Unlike “convenience samples” of most fluoride-cognition studies, the new study comprised a nationally representative sample of people.
What does Dr. Rob Warren say about fluoride research?
Dr. Rob Warren, the lead author of the new study, talked to CNN about the new paper and explained how it strengthens the overall body of evidence.
“Imagine testing some new drug for heart disease and the recommended dosage is 100 milligrams, and then your study compares people who get a million milligrams to people who get half a million milligrams,” Dr. Warren said. “Well, that doesn’t tell you anything about the effect of getting 100 milligrams versus getting nothing. That’s kind of the world we’re in with fluoride research. It’s important to know that if you get a toxic dose, really bad things happen to your body, but that’s not relevant for the public policy discussion.”
Who contributed to the study published in Science Advances?
The team of authors included six sociologists and one neurologist. Science Advances is a journal managed by the American Association for the Advancement of Science.