• The National Toxicology Program (NTP) has found a link between higher levels of fluoride exposure and lower IQ in children.
• This conclusion is based on a systematic review of the published scientific literature on the association between fluoride exposure and neurodevelopment and cognition.
• The review focused on studies where total fluoride exposure exceeded 1.5 milligrams per liter, mainly from non-U.S. countries.
• The U.S. Public Health Service currently recommends a fluoride level of 0.7 mg/L in community water supplies.
• More research is needed to understand the potential health risks of low fluoride exposure.

August 23, 2024 — The National Toxicology Program (NTP) released a report in August 2024 titled “NTP Monograph on the State of the Science Concerning Fluoride Exposure and Neurodevelopment and Cognition: A Systematic Review.” The report concludes that there is “moderate confidence” in the scientific evidence that shows an association between higher levels of fluoride exposure and lower IQ in children.

The NTP conducted this systematic review to evaluate the extent and quality of evidence linking fluoride exposure to neurodevelopmental and cognitive effects in humans. The review included studies on humans, experimental animals, and mechanistic data. The most common exposure assessment measures were drinking water concentrations and estimates of total fluoride exposure.

The review showed that 18 out of 19 good-quality studies found that children exposed to more fluoride tended to have lower IQs. These studies were conducted in five countries, including Canada, China, India, Iran, and Mexico, where some pregnant women, infants, and children received total fluoride exposure amounts higher than 1.5 mg fluoride/L of drinking water.  NTP’s review, which focused on total fluoride exposure from all sources, was not designed to evaluate the health effects of fluoridated drinking water alone. The U.S. Public Health Service recommends 0.7 mg/L of fluoride in community water supplies, which is lower than the levels associated with lower IQ in the NTP review.  

The NTP emphasizes that its investigation is still ongoing and that more research is needed to determine whether low levels of fluoride could be harmful. This report is part of their ongoing work and might help government agencies make rules about the safe use of fluoride.

Citation; Download the Full Report.

National Toxicology Program (NTP). 2024. NTP monograph on the state of the science concerning fluoride exposure and neurodevelopment and cognition: a systematic review. Research Triangle Park, NC: National Toxicology Program. NTP Monograph 08. https://doi.org/10.22427/NTP-MGRAPH-8

Full Report PDF.

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