Although more research is needed to know for sure, it appears that excessive fluoride exposure is linked to poorer cognition in children; it’s important to note that community fluoridation in the United States and Canada is far below this level. A meta-analysis of 8 cross-sectional and cohort studies did not find that fluoride exposure via community water fluoridation affects IQ scores in children. However, high fluoride exposure (3.7 mg/L) from natural groundwater in certain geographical areas (e.g., parts of China and India) was associated with lower IQ when compared with lower fluoride exposure (0.7 mg/L). There was no difference in IQ between mean exposure to 0.9 mg/L fluoride when compared to 0.3 mg/L fluoride.[1] Another meta-analysis of 26 observational studies mostly conducted in China found that high fluoride exposure from water is associated with lower intelligence compared to normal fluoride exposure.[2] This data is limited by its observational nature and the presence of various confounding factors. For example, the impact of socio-economic status or exposure to environmental toxins was not able to be controlled.
Does fluoride impact neurological development in children?
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•Last Updated: May 16, 2025
Excessive fluoride exposure may be associated with poorer cognition in children, particularly in areas with naturally high fluoride levels, whereas community fluoridation in the U.S. and Canada occurs at levels that are not concerning. However, studies show no significant effect on IQ from typical community fluoride levels, and findings are limited by confounding factors.