Fluoride: Potential Developmental Neurotoxicity
Fluoride is added to municipal water supplies and dental products, such as toothpaste, to prevent or reduce tooth decay. People are primarily exposed to fluoride from drinking water and use of fluoridated dental products, with water fluoridation representing 30% to 70% of a typical individual’s total exposure. Fluoride is also used in consumer products, such as cleaning supplies, and industrial applications. Workers in some occupations may be exposed to fluoride by inhaling fluoride compounds at their place of employment.
Systematic Reviews on Potential Health Effects of Fluoride
Completed systematic review
In 2016, NTP completed a systematic review of the published animal literature looking at neurobehavioral effects of exposure to fluoride during development and adulthood in rats and mice. The assessment found a low to moderate level of evidence that support adverse effects on learning and memory in animals exposed to fluoride in the diet or drinking water. The evidence was strongest in animals exposed as adults and weaker in animals exposed during development.
The animal studies typically evaluated developmental exposure to fluoride at levels higher than 0.7 parts per million, the recommended level for community water fluoridation in the United States. Additional research is underway to attempt to replicate these findings at water concentrations closer to the levels used in community water fluoridation.
Ongoing systematic review
NTP is currently conducting a systematic review to evaluate potential neurobehavioral effects from exposure to fluoride during development that includes consideration of human epidemiology, additional experimental animal studies, and mechanistic data.
- Protocol for ongoing systematic review (July 2017)
- NTP Board of Scientific Counselors Meeting (December 1-2, 2015)
- Request for Information on Nomination (Federal Register notice for nomination – October 7, 2015 PDF HTML)
- Public Comments (November 2015)
- Completed Systematic Review: Preferred citation: NTP (National Toxicology Program). 2016. Systematic Literature Review on the Effects of Fluoride on Learning and Memory in Animal Studies. NTP Research Report 1. Research Triangle Park, NC: National Toxicology Program.