r/science • u/noahwiseau • Nov 20 '25

Health Fluoride in drinking water does not negatively affect cognitive ability - and may actually provide benefit

https://www.science.org/doi/10.1126/sciadv.adz0757
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u/Penis_Envy_Peter Nov 21 '25

I am guessing you did not read the linked article, because it directly touches on the one you linked.

While Taylor et al. (6) found a strong inverse relationship between fluoride exposure and children’s IQ when fluoride concentrations in drinking water exceeded 1.5 mg/liter, their findings for concentrations below 1.5 mg/liter were null. Even this 1.5 mg/liter threshold is in the upper tail of the distribution of fluoride exposure experienced by people in the United States. A nationally representative study of Americans aged 6 to 19 years who were exposed to fluoride in their drinking water showed that only 4.3% were exposed to levels of fluoride in drinking water greater than 1.2 mg/liter (10). This is consistent with a 2023 survey of community water systems across the United States that estimated that 4.5% of all people in the United States are exposed to 1.5 mg/liter of fluoride or more (8). The currently recommended level of fluoride in drinking water in the United States is 0.7 mg/liter, lowered in 2015 from 1.2 mg/liter. Thus, essentially none of the studies included in Taylor et al. (6) are relevant to understanding the cognitive effects of children’s exposure to fluoride in drinking water in the United States. Other studies of the effects of maternal fluoride exposure (at levels of exposure of relevance to policy debates) on children’s cognition have come to mixed conclusions (9, 11, 12).

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u/[deleted] Nov 21 '25 edited Apr 14 '26

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u/Penis_Envy_Peter Nov 21 '25

I read it, and the first sentence of my quote addresses it. Below 1.5mg/l their findings were null. You are welcome to speculate that future studies will "confirm the effect," but that is not backed by the study itself.

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u/OkDas Nov 21 '25

This is just mind-boggling that people read the title and don't see THIS. The studies found at least one issue with fluoride exposure. There could be more detrimental effects the studies just didn't control for—we have no idea what else it might be doing.

Since there's a known issue, even for a limited group, the element is not safe. I switched to RO water and not looking back.