Study Links High Levels of Fluoride to Cognitive Impairment in Children

Long-term consumption of water with excessive levels of fluoride may be associated with cognitive impairment in children, according to a new pilot study by Tulane University.

The study, published in Neurotoxicology and Teratology, was conducted in rural Ethiopia, where farming communities use wells with varying levels of naturally occurring fluoride, many of which far exceed established drinking water standards. Fluoride plays a crucial role in the prevention of tooth decay, but there's growing concern about overconsumption and its potential effects on cognition. For the investigation, researchers compared the cognitive ability of children according to their region and level of fluoride exposure.

The researchers chose to study the Ethiopian Rift Valley due to its residents' consistent exposure to stable, naturally occurring fluoride levels. The World Health Organization (WHO) recommends fluoride levels below 1.5 mg/L; in the Ethiopian Rift Valley, naturally occurring fluoride levels ranged from 0.4 to 15.5 mg/L. This, coupled with similar lifestyles in neighboring villages, minimized potential confounding variables, the authors explained.

For the investigation, researchers enlisted 74 school-aged children to evaluate their cognitive abilities using two methods: a drawing test, where children sketched common objects like a house and were scored based on their level of detail, and a standardized computerized memory test, designed to be unbiased towards language or culture. The results showed that higher exposure to fluoride in drinking water was associated with more errors on the drawing and memory tests.

Tewodros Godebo, PhD, the study's lead author and Assistant Professor of Environmental Health Sciences at Tulane University's School of Public Health and Tropical Medicine, noted that while the direct causation between fluoride exposure and neurotoxicity remains ambiguous, he anticipates that these preliminary results will encourage further investigation into the possible cognitive effects of fluoride exposure.

"Though further epidemiological studies are needed to validate the findings, these results add to the growing concern about the potential neurotoxic effects of fluoride, especially during early brain development and childhood," Godebo said. "These tests affirmed a clear association between high fluoride and cognitive impairment."