A recent pilot study conducted by Tulane University has revealed a potential association between prolonged consumption of water with fluoride levels exceeding established drinking water standards and cognitive deficits in children.
Published in the journal Neurotoxicology and Teratology, the research was conducted in rural Ethiopia, where communities rely on wells containing naturally occurring fluoride levels ranging from 0.4 to 15.5 mg/L, well above the World Health Organization’s recommended threshold of less than 1.5 mg/L.
Seventy-four school-aged children participated in the study, and their ability to draw familiar objects, like a donkey or a house, was assessed. Scores were assigned based on the accuracy of their drawings. In addition, a standardized computerized memory test, designed to be language and culture-neutral, was employed to gauge cognitive abilities.
The study findings suggested a correlation between higher fluoride exposure in drinking water and increased errors on both the drawing and memory tests. Tewodros Godebo, the lead author and assistant professor of environmental health sciences at Tulane University School of Public Health and Tropical Medicine, acknowledged that the “causal relationship between fluoride exposure and neurotoxicity remains unclear.” Nevertheless, he hopes these initial findings will stimulate further investigations into the potential cognitive consequences of fluoride exposure.
While fluoride is vital for preventing dental decay, previous epidemiological studies in rural Chinese and Indian communities have associated excess fluoride intake with lower IQs. Additionally, animal research has indicated that fluoride can cross the placenta and blood-brain barriers, suggesting that excess fluoride exposure, particularly in regions lacking alternative water sources, may be a chronic concern beginning at conception.
More than 200 million people worldwide are estimated to be exposed to elevated fluoride levels in their drinking water. The Ethiopian Rift Valley, where the study took place, serves as an ideal research location due to the consistent, naturally occurring fluoride levels experienced by those raised in the region. These individuals also share similar lifestyles with neighboring communities, reducing the potential for confounding factors.
Godebo’s future research plans include replicating the findings in Ethiopia with a larger group of children and examining the cognitive abilities of children in low-fluoride Ethiopian communities for any signs of cognitive impact. He emphasized the importance of such studies for the public and government agencies in assessing the safety and risks associated with water fluoridation in drinking water systems.