The researchers emphasized the importance of considering the overall findings from similar longitudinal studies to better understand the long-term effects of fluoride on brain development
A new study has raised concerns about the impact of fluoride exposure on childhood cognition, linking elevated fluoride levels in drinking water to impaired cognitive abilities in children. Published in the journal Environmental Health Perspectives, the research from Karolinska Institutet in Sweden supports earlier studies suggesting that exposure to fluoride during the foetal stage or early childhood could negatively affect cognitive development.
Fluoride naturally occurs in drinking water as fluoride ions, typically at low concentrations in public water supplies. However, in some countries, including the United States, Canada, Chile, Australia, and Ireland, fluoride is added to municipal water supplies at concentrations around 0.7 mg per litre to prevent dental caries (cavities). While fluoride’s dental benefits are well-documented, concerns have arisen regarding its potential health risks, particularly when exposure occurs during critical stages of brain development.
Maria Kippler, an associate professor at the Institute of Environmental Medicine at Karolinska Institutet, emphasized that the addition of fluoride to drinking water is controversial. “Our results support the hypothesis that even relatively low concentrations of fluoride can impact children’s early development,” she stated. “Given the concern about health risks, the addition of fluoride to drinking water is widely debated in countries like the USA and Canada.”
The study followed 500 mothers and their children in rural Bangladesh, a region where fluoride occurs naturally in drinking water. The concentrations of fluoride in the water in Bangladesh are similar to those found in many other countries worldwide. The researchers aimed to investigate the association between early fluoride exposure and cognitive abilities in children, with a particular focus on the effects during the foetal stage and early childhood.
To measure fluoride exposure, researchers analyzed urine samples from both the mothers and children. Urine fluoride concentrations reflect ongoing exposure to all sources of fluoride, including drinking water, food, and dental care products. However, the study noted that dental care products like toothpaste do not significantly contribute to fluoride exposure, as these products are not typically ingested.
The findings revealed that the median fluoride concentration in the urine of the pregnant Bangladeshi women was 0.63 mg/L. By the time the children reached the age of ten, those who had more than 0.72 mg/L of fluoride in their urine demonstrated lower cognitive abilities compared to those with less fluoride in their urine. The most pronounced effects were seen in verbal reasoning skills and the ability to process sensory information.
While the study focuses on fluoride exposure in rural Bangladesh, researchers noted that the concentrations of fluoride found in the urine of the participants are similar to levels found in other countries that add fluoride to their water supplies. This highlights the global relevance of the study and its potential implications for public health policy, particularly in countries that fluoridate drinking water.
The researchers emphasized the importance of considering the overall findings from similar longitudinal studies to better understand the long-term effects of fluoride on brain development. Although fluoride continues to be recommended for cavity prevention, the study calls for further examination of its potential impact on child health, especially at vulnerable stages of development.
As the debate over fluoride in drinking water continues, this study adds to the growing body of research that urges caution and further investigation into the possible cognitive risks associated with fluoride exposure during early childhood.
