February 29, 2024

Water Worries: Excess Fluoride Linked to Cognitive Impairment in Children

Water Worries: Excess Fluoride Linked To Cognitive Impairment In ChildrenChild Drinking Water Art Concept - Water Worries: Excess Fluoride Linked To Cognitive Impairment In Children

A study from Tulane University suggests that high fluoride levels in drinking water may impair children’s cognitive abilities, emphasizing the need for further research on its potential neurotoxic effects.

A study of 74 children in rural Ethiopian villages with a wide range of naturally occurring fluoride in drinking water found that children exposed to excess fluoride performed worse on cognition tests.

Long-term consumption of water with fluoride levels far above established drinking water standards may be linked to cognitive impairments in children, according to a new pilot study from Tulane University.

The study, published in the journal Neurotoxicology and Teratology, was conducted in rural Ethiopia where farming communities use wells with varying levels of naturally occurring fluoride ranging from 0.4 to 15.5 mg/L. The World Health Organization (WHO) recommends fluoride levels below 1.5 mg/L. The United States Environmental Protection Agency (EPA) sets 4.0 mg/L as the maximum amount of fluoride that is allowed in water from public water systems.

Research Methodology

Researchers recruited 74 school-aged children and rated their ability to draw familiar objects such as a donkey or a house, with scores reflecting any missing details. They used a standard computerized memory test which is language and culture neutral as another tool to measure cognitive ability.

The study found that higher exposure to fluoride in drinking water was linked to more errors on the drawing and memory tests. Lead author Tewodros Godebo, assistant professor of environmental health sciences at Tulane University School of Public Health and Tropical Medicine, said the “causal relationship between fluoride exposure and neurotoxicity remains unclear” but he hopes these preliminary findings will spur more research into the potential cognitive impacts of fluoride exposure.

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In rural Ethiopia, farming communities utilize wells with a wide range of naturally occurring fluoride levels – from 0.4 to 15.5 mg/L. Notably, the World Health Organization advises keeping fluoride concentrations under 1.5 mg/L in drinking water.

Implications and Previous Findings

“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.”

Fluoride is essential for preventing tooth decay. However, excess intake of fluoride has been linked to lower IQs in past epidemiological studies in rural communities in China and India.

Additionally, past animal research has shown that fluoride can cross the placenta and blood-brain barriers. In regions with no alternative water sources, this means excess fluoride exposure could be a chronic issue that begins at conception.

According to the US CDC, the Public Health Service recommendation for community water flurodation is 0.7 milligrams per liter, as this is the optimal level of fluoride in drinking water to provide enough fluoride to prevent tooth decay in children and adults while limiting the risk of dental fluorosis.

Global Impact and Further Research

Over 200 million people worldwide are estimated to be exposed to high fluoride levels in their drinking water. The Ethiopian Rift Valley, where this study was conducted, is an ideal research area for investigations of potential impacts because those raised in the area have consistent exposure to stable, naturally occurring fluoride levels and share similar lifestyles with surrounding villages, limiting the risk of confounding factors.

Godebo hopes to replicate the results in Ethiopia with a larger cohort of children and study the cognition of children in low-fluoride Ethiopian communities for potential signs of cognitive impact.

“We have a unique opportunity to study low fluoride communities in the same setting as high fluoride communities, so we can determine if fluoride is a neurotoxicant at low levels,” Godebo said. “Such studies are important to the public and government agencies to determine the safety and risk of water fluoridation in drinking water supply systems.”

Reference: “Association between fluoride exposure in drinking water and cognitive deficits in children: A pilot study” by Tewodros Rango Godebo, Marc Jeuland, Redda Tekle-Haimanot, Biniyam Alemayehu, Arti Shankar, Amy Wolfe and Nati Phan, 9 September 2023, Neurotoxicology and Teratology.
DOI: 10.1016/j.ntt.2023.107293

Co-authors for the study included Nati Pham and Arti Shankar of Tulane University, Marc Jeuland of Duke University, Amy Wolfe of University of Kentucky, and Redda Tekle-Haimanot and Biniyam Alemayehu of Addis Ababa University.

Funding: NIH/National Institute of Environmental Health Sciences