Since 1945, cities and municipalities in the United States have added fluoride to community water systems to prevent tooth decay. As of 2020, the U.S. Centers for Disease Control and Prevention reports that nearly 73 percent of Americans have fluoridated water; however, there is growing concern about the negative effects of fluoride exposure.

An article in Neurotoxicology and Teratology, a publication dedicated to the effects of chemical and physical agents on the nervous system, investigated the association between fluoride exposure in drinking water and cognitive deficits among children. The study involved 74 school-aged children living in rural Ethiopia. Researchers measured the participants’ exposure to fluoride through samples of community-based drinking water wells and urine samples.

Cognitive performance was measured using two assessments: the children’s ability to draw familiar objects and a standardized, memory and new-learning assessment. The results showed that fluoride levels in drinking water were negatively associated with cognitive function, and that cognitive deficits were particularly strong among children exposed to high levels of fluoride.

The study’s authors highlighted the need for additional studies involving children and adults to understand the potential neurotoxicity of low fluoride levels known to protect against dental cavities, as well as the effects of elevated fluoride levels in drinking water. Such research is essential to protect the cognitive health of children and to inform public health policymaking.