New US Study Reveals Fluoride’s Positive Impact on Cognition

Research conducted by the University of Minnesota has unveiled a surprising connection between fluoride levels in drinking water and cognitive function. The largest study of its kind in the United States examined the impact of fluoride on cognitive outcomes, revealing that recommended fluoride levels may actually enhance brain function rather than hinder it.

This comprehensive study analyzed data from a subset of **26,820 individuals** drawn from the **1980 High School and Beyond cohort study**, involving **58,270** sophomores and seniors from **1,020** American high schools. Participants were reinterviewed multiple times until 2021, providing a unique longitudinal perspective over **more than 40 years**. Researchers matched this academic data with student locations and fluoridation status, utilizing information from the **US Department of Health and Human Services’ Fluoridation Census** (1967-1993) and fluoride levels measured in untreated groundwater from **38,105** wells between **1988 and 2017**.

The findings indicate that children exposed to recommended fluoride levels in drinking water, which were set between **0.7 mg/liter and 1.2 mg/liter** from **1962 to 2015**, and maintained at **0.7 mg/L** since 2015, exhibited higher scores in vocabulary, reading, and mathematics by their final school year. While the advantages continued into middle age, the results were not statistically significant.

“This is a great example of understanding the data and scientific research used to draw conclusions,” stated Gina Rumore, one of the study’s authors at the Life Course Center. She emphasized that while extremely high fluoride levels can be toxic, fluoride at recommended levels is safe and beneficial. “Fluoridating drinking water is known to have massive oral health benefits, and now it appears that it also leads to better – not worse – cognitive test performance.”

Fluoride has long sparked debate, especially following the recent move by the US Health and Human Services to consider removing it from local water supplies. States such as **Utah** and **Florida** have already eliminated fluoride from their water systems, while a **2024 investigation** by **US News & World Report** found that ten states have less than half of their residents receiving fluoridated public water.

The controversy surrounding fluoride stems from its introduction in **Grand Rapids, Michigan**, in **January 1945**, where evidence suggested a significant reduction in tooth decay. Despite its health benefits, the practice faced strong opposition, leading to misinformation fueled by smaller studies from countries like **China**, **India**, and **Iran**, where high levels of fluoride exposure correlated with adverse health outcomes. Importantly, these studies involved fluoride concentrations many times greater than those found in the United States.

“It is vitally important for the public – and people who influence public policy – to know that there is absolutely no credible scientific evidence to support the claim that putting fluoride in municipal drinking water at recommended levels harms children’s IQ,” noted John Robert Warren, another author of the study. “In fact, the opposite appears to be true.”

The researchers also conducted supplementary analyses to account for community variables, confirming that children who remained in the same community throughout their schooling exhibited similar cognitive patterns. They aimed to distinguish the biological effects of fluoride from social, cultural, and economic factors that could influence cognitive outcomes.

“Municipalities that fluoridate their water may also be places that make other investments – in education, housing, healthcare, etc. – that lead to better cognitive outcomes,” the researchers explained.

Despite the study’s strengths, the authors acknowledged limitations. They expressed a desire for more comprehensive data on participants’ living situations from conception through late adolescence, as well as more precise information regarding fluoride consumption. They noted that estimating fluoride exposure based solely on water chemistry may not fully capture individual consumption patterns.

Nevertheless, the results strongly suggest that exposure to fluoride at levels typically found in the United States has positive implications for adolescent cognition and does not harm cognitive functioning later in life. The study also did not find any correlation between fluoride exposure and the prevalence of neurodevelopmental conditions in children and adolescents.

The implications of this research are significant. “This study provides important longer-term evidence that community water fluoridation is a safe and effective public health measure,” stated Matthew Hobbs, Associate Professor from the University of Canterbury in New Zealand. He emphasized that these findings align with decades of international research that discredits concerns about fluoride and cognition stemming from studies involving populations exposed to excessively high fluoride levels.

“From a public health perspective, this matters,” Hobbs continued. “Community water fluoridation remains one of the most equitable and cost-effective ways to prevent tooth decay, particularly for children and communities with limited access to dental care.”

The enduring benefits of fluoride for dental health have been confirmed over decades of research. “This research demonstrates that fluoridation is safe for all ages,” noted Justin Wall from Te Rōpū Niho Ora (Oral Health New Zealand). He remarked on the study’s comprehensive approach, emphasizing its significance in a country that often scrutinizes public health policies.

The study’s findings were published in the journal Science Advances, marking a pivotal contribution to the ongoing discourse surrounding fluoride in drinking water.