A recent study conducted by Karolinska Institutet in Sweden reveals that exposure to fluoride during fetal development or early childhood may negatively impact children’s cognitive abilities. The research, published in Environmental Health Perspectives, supports earlier studies that suggested fluoride exposure could impair cognition, particularly affecting areas like spatial processing and visual motor skills.
Fluoride naturally occurs in drinking water, but its concentration is usually low in public water supplies. In countries like the USA, Canada, Chile, Australia, and Ireland, fluoride is added to the municipal water supply at a concentration of around 0.7 mg per liter to prevent dental caries. However, the practice has sparked debates regarding potential health risks, especially concerning children’s development.
Maria Kippler, an associate professor at the Institute of Environmental Medicine at Karolinska Institutet, emphasized the study’s significance. “Our results support the hypothesis that even relatively low fluoride concentrations can impact children’s early development,” Kippler said.
Study Design: Tracking 500 Mothers and Children in Bangladesh
The study tracked 500 mothers and their children in rural Bangladesh, a region where fluoride naturally occurs in drinking water at levels comparable to those found in other countries. Researchers assessed the children’s cognitive abilities at ages five and ten using established psychological tests. To measure fluoride exposure, they analyzed urine samples from both mothers and children, reflecting ongoing exposure from drinking water, food, and dental care products.
Although fluoride is commonly found in toothpaste, Kippler reassured that it does not typically contribute significantly to exposure. “Fluoride in toothpaste is important for preventing caries, but it’s essential to encourage young children not to swallow toothpaste during brushing,” she said.
Findings: Fluoride Linked to Decreased Cognitive Function
The study found that the median fluoride concentration in the urine of pregnant women in Bangladesh was 0.63 mg/L. Increased fluoride levels in pregnant women correlated with a decline in their children’s cognitive abilities at ages five and ten. Even though the fluoride levels in drinking water from private wells in Bangladesh were below World Health Organization (WHO) limits, they still appeared to affect cognitive function.
At age ten, children with urinary fluoride concentrations exceeding 0.72 mg/L showed lower cognitive abilities compared to those with less fluoride in their urine. The most notable cognitive impacts were observed in verbal reasoning and sensory processing skills.
Interestingly, fluoride exposure associated with impaired cognitive development was found to be below the WHO and EU threshold of 1.5 mg/L for fluoride in drinking water. No statistically significant link was found between urinary fluoride concentrations in five-year-olds and their cognitive abilities, likely due to shorter exposure duration and greater variability in fluoride uptake in younger children.
No Safe Threshold for Fluoride
The study revealed that prenatal fluoride exposure was inversely related to cognitive abilities at both five and ten years of age. Notably, there appeared to be no threshold below which fluoride exposure did not affect cognition. Kippler also noted that the impact of prenatal fluoride exposure was more pronounced in girls than boys at age ten, though the difference was not statistically significant.
Need for Further Research
While the study provides compelling evidence, it is observational, meaning no definitive conclusions about causality can be made. The use of single-spot urine samples may have introduced some inaccuracies in measuring fluoride exposure, and the researchers stressed the importance of additional longitudinal studies to confirm the results.
The research team plans to expand their investigation into other populations and develop experimental models to explore the underlying molecular mechanisms. “There is a need for more research to provide a solid foundation for reassessing fluoride health risks and determining safe thresholds for drinking water, food, and dental care products, particularly for children,” Kippler emphasized. “Even minor changes in cognition at the population level can have significant public health consequences.”
The study was primarily funded by national grants from the Swedish Research Council and the Swedish Research Council for Environment, Agricultural Sciences, and Spatial Planning. The researchers declared no conflicts of interest.
Related topic:
Menopausal Symptoms Linked to Increased Dementia Risk
Early Nutrition and Brain Development in Preterm Infants
Chronic Stress Linked to Higher Stroke Risk in Younger Women
