A new study by researchers at Karolinska Institutet sheds light on the potential cognitive risks associated with fluoride exposure during early development. Published in the journal Environmental Health Perspectives, the research raises concerns about fluoride in drinking water and its impact on public health.
Fluoride, which occurs naturally in drinking water or is added to municipal supplies in several countries—including the USA, Canada, Chile, Australia, and Ireland—is commonly used to combat dental caries. While the addition of fluoride is often seen as a public health measure, its long-term safety has sparked considerable debate.
“Given the concern about health risks, adding fluoride to drinking water is controversial and has been widely debated in the USA and Canada,” says Maria Kippler, Associate Professor at Karolinska Institutet.
The researchers tracked 500 mothers and children in rural Bangladesh, where naturally occurring fluoride levels in water are similar to those in many countries. Measuring fluoride exposure through urine samples found significant links between higher prenatal fluoride exposure and reduced cognitive abilities in children aged five and ten. These effects were most noticeable in verbal reasoning and sensory input processing.
Children with urine fluoride levels exceeding 0.72 mg/L showed the greatest developmental impairments. Importantly, the exposures tied to these impairments were below the World Health Organization and European Union’s threshold for fluoride in drinking water, set at 1.5 mg/L.
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Interestingly, no significant association was observed between fluoride levels in five-year-old children and their cognitive performance, which researchers attributed to shorter exposure duration and variability in fluoride absorption in younger bodies.
Given the study’s observational nature, the researchers stress the need for further investigation to establish causality and uncover molecular mechanisms.
“More research is needed to create a robust basis for reviewing fluoride health risks and thresholds,” Dr. Kippler emphasizes. The team aims to expand its research to other populations and experimental models.
Journal Reference
Taranbir Singh, Klara Gustin, Syed Moshfiqur Rahman, Shamima Shiraji, Fahmida Tofail, Marie Vahter, Mariza Kampouri, Maria Kippler et al. “Prenatal and childhood exposure to fluoride and cognitive development: findings from the longitudinal MINIMat cohort in rural Bangladesh”. Environmental Health Perspectives, DOI: 10.1289/EHP14534