The benefit-risk trade-off for community water fluoridation has changed.
Robert F. Kennedy Jr.’s announcement last week that he will direct the Centers for Disease Control and Prevention to stop recommending fluoridation of drinking water prompted prominent medical and dental groups to denounce the decision as an affront to decades of public health doctrine. But neither they, nor the health secretary, are providing the full picture.
Though fluoride has been instrumental in preventing tooth decay, emerging research supports the need for a revised fluoridation policy. Even an outright ban — though extreme and unnecessary — would not be a public health catastrophe.
I know this will not be a popular view among those incensed by the Trump administration. Kennedy has already done great damage as head of Health and Human Services: He has overseen unprecedented cuts to biomedical research and decimated entire divisions within the CDC and other agencies. He has hired a discredited skeptic to lead vaccine research and continues to play down the seriousness of a worsening measles outbreak. So, it is understandable for people to harbor hostility toward his actions.
But the case for community water fluoridation — long hailed as one of the greatest public health achievements of the last century — is not as clear as it once was. Two evolving factors have altered the benefit-risk trade-off.
First, Americans are now being exposed to fluoride in new ways. Drinking water used to be the primary vehicle to deliver the mineral, which strengthens tooth enamel and helps reverse early decay. But widespread adoption of fluoride toothpaste and other fluoride-containing oral products changed that. Plus, some communities have naturally occurring fluoride in their water supply and do not need more added.
A 2024 Cochrane review of 157 studies found that research conducted in 1975 or earlier demonstrated a marked association between water fluoridation and reduction in dental caries. But those done after 1975 showed that fluoridation may lead to slightly less decay in children’s baby teeth, and were inconclusive regarding effects on their permanent teeth. Indeed, many Western countries, including Germany, Israel, Denmark and Sweden, have stopped fluoridation.
Second, growing evidence shows that fluoride is not harmless. Research published in respected journals such as JAMA Pediatrics and JAMA Network Open have suggested associations between pregnant women drinking fluoridated water and cognitive and neurobehavioral problems in their children. During the Biden administration, HHS’s National Toxicology Program published a report that found “moderate confidence” linking consumption of fluoridated water with lower IQ in children.
Critics of those findings have argued that most studies uncovered associations at water fluoride concentrations at or above 1.5 milligrams per liter, which is more than double the CDC’s recommended level of 0.7 milligrams per liter. They are right: At 0.7 milligrams, the benefit of fluoridation probably outweighs its risks.
The problem is that the Environmental Protection Agency’s limit for fluoride is set at 4 milligrams per liter, meaning state and local governments can decide to add fluoride to their water supply so long as it stays below 4 milligrams — even though this is more than three times the level associated with harm from the federal government’s own studies.
A reexamination of this limit is long overdue. The EPA announced last week that it would “expeditiously review” the science on fluoride levels. The agency’s administrator, Lee Zeldin, is right to heed Kennedy’s call.
Similarly, I think it is appropriate for Kennedy to ask the CDC to revise its recommendations. As many as 3 million Americans live in areas that have levels of fluoride in their tap water that exceed 1.5 milligrams per liter. The CDC could alert these communities and issue guidance for pregnant women to filter their water. For regions where water is naturally fluoridated, the CDC could advise policymakers against adding more. It could also urge everyone, especially those in communities with low levels of water fluoride, to use fluoride-containing toothpaste.
These would be reasonable recommendations that consider the complexities of the fluoride debate. Just as Kennedy would be wrong to say no level of fluoride is safe, those who speak only of fluoride’s benefits would be at risk of ignoring science.
Reestablishing trust in public health requires a nuanced approach. The medical establishment — and the public — should evaluate policies on their scientific merits and resist knee-jerk reactions based on the person proposing the change.
Dr. Leana Wen is a trusted voice in public health, known for her ability to cut through political noise with science-based clarity and nuance. As a physician, former public health commissioner, and prominent media contributor, Dr. Wen brings a rare combination of medical expertise, policy insight, and clear communication—making her an outstanding keynote speaker for any event focused on health, leadership, or science advocacy. To host this WWSG thought leader at your event, contact us.
