Context Check: Is Water Fluoridation Safe?

Meta studies

At this time, the current evidence does not allow us to state that fluoride is associated with neurological damage.

For reductions in children’s IQ, the authors acknowledge a biological mechanism of action has not been elucidated, and the dose response curve is not clear at lower concentrations

The Community Preventive Services Task Force recommends community water fluoridation based on strong evidence of effectiveness in reducing tooth decay.

PDF of Preventing Dental Caries: Community Water Fluoridation (2000 Archived Review)

Collective evidence from the recent CADTH reports and the current review indicates there is insufficient evidence to conclusively conclude that fluoride exposure at the Canadian water fluoride levels (optimum at 0.7 mg/L) affects neurological development in children and adolescents in Canada.

Community Water Fluoridation Exposure: A Review of Neurological and Cognitive Effects – A 2020 Update

Scientists

https://www.ada.org/resources/community-initiatives/fluoride-in-water

Journalism

A report released in August by the U.S. Department of Health and Human Services found that drinking water containing more than 1.5 milligrams per liter was "consistently associated with lower IQ in children."

But the report, which evaluated studies conducted in Canada, China, India, Iran, Pakistan and Mexico, noted that the fluoride levels found to cause such risks were more than twice as high as the amount U.S. officials recommend be added to public water systems. Fluoride levels that high are mostly found in other countries and a tiny minority of U.S. communities.

The report also did not specify how much IQ levels dipped or whether adults could also be affected.

The NTP defines “high levels” as 1.5 milligrams per liter of water or higher. This is more than twice the fluoride concentration typically found in U.S. tap water: The Centers for Disease Control and Prevention recommends that U.S. community water systems contain about 0.7 milligrams per liter.

According to the NTP report, about 0.6% of the U.S. population — approximately 1.9 million people — are on water systems with naturally occurring fluoride levels of 1.5 milligrams per liter or higher. It’s important enough that I’ll repeat it: These high levels are naturally occurring and not the result of artificial water fluoridation programs. So let’s make this crystal clear: This study does not provide evidence against current community water fluoridation practices.

Politics

Government Statements

U.S. Public Health Service Recommendation for Fluoride Concentration in Drinking Water for the Prevention of Dental Caries

PDF of Fluoride in Drinking-water Background document for development of WHO Guidelines for Drinking-water Quality