Research findings

New findings published in JAMA Pediatrics (January 2025) have reignited the debate over fluoride’s safety. A meta-analysis of 74 studies from 10 countries found a strong link between fluoride exposure and lower IQ scores in children. Key highlights include:

• IQ Reduction: A 1 mg/L increase in urinary fluoride corresponds to a 1.63-point drop in IQ (95% CI: -2.33 to -0.93; P < .001).
• Robust Results: Among high-quality studies, the reduction was 1.14 points per 1 mg/L increase (95% CI: -1.68 to -0.61; P < .001).
• Consistent Trends: Across 59 studies measuring fluoride exposure, a pooled analysis showed a significant inverse relationship with IQ (pooled SMD: -0.45; 95% CI: -0.57 to -0.33; P < .001).

Most studies were conducted outside the U.S., where fluoride levels are often higher, but the findings have sparked concern about cumulative exposure from various sources.

New fluoride guidelines

• Current Recommendations: The U.S. Public Health Service (PHS) advises an optimal fluoride level of 0.7 mg/L to prevent cavities while minimizing risks of dental fluorosis.
• EPA Standards: The Environmental Protection Agency (EPA) sets a maximum contaminant level goal of 4 mg/L, though many states impose stricter limits.

These guidelines reflect efforts to balance public health benefits with safety concerns—a balance now under intense scrutiny.

Tap water above the limit

In the United States, the U.S. Public Health Service (PHS) recommends a fluoride concentration of 0.7 milligrams per liter (mg/L) and the Environmental Protection Agency (EPA) has established a maximum contaminant level (MCL) of 4.0 mg/L however some utilities have fluoride levels detected above these levels.

Remember, the study found fluoride levels above 1.5 mg/L (parts per million) of fluoride in drinking water were linked to lower IQ scores in children.

Despite these limits estimates predict between 100,000 and 2 million americans are exposed to tap water with fluoride above levels of 1.5 mg/L.

Policy Shifts and Public Debate

The Trump administration has announced plans to advise all U.S. water systems to eliminate fluoride. Robert F. Kennedy Jr. underscored this decision, citing links between fluoride and conditions like IQ loss, arthritis, neurodevelopmental disorders, and thyroid disease. He called it a step toward “Making America Healthy Again.”

This policy shift follows a September 2024 federal court ruling, which concluded that fluoride poses an unreasonable risk to children’s cognitive development. The court directed the EPA to take action—a directive that has now gained significant traction.

Some experts are divided

The debate has divided public health experts:

• Support for Fluoridation: Organizations like the American Dental Association (ADA) defend water fluoridation, emphasizing its proven role in preventing tooth decay.
• Voices of Concern: Experts like Dr. Philippe Grandjean warn of broader societal impacts, noting that even small IQ reductions can double rates of intellectual disability within communities.
• National Toxicology Program (NTP): The NTP found moderate evidence linking higher fluoride exposure to lower IQ, though data on current U.S. standards (0.7 mg/L) remains inconclusive.

The narrative is changing

Globally, skepticism about fluoridation is growing:

• European Action: Countries such as Austria, Belgium, and Italy have abandoned water fluoridation, citing safety concerns and alternative dental health strategies.
• Broader Trends: These decisions align with increasing caution around fluoride use in public health.

What this means

Water fluoridation—once hailed as a landmark public health achievement—is now under the microscope. While its role in reducing tooth decay remains undisputed, emerging evidence of cognitive risks cannot be ignored.

As policymakers weigh benefits against risks, rigorous, high-quality research will be essential to guide future decisions. In the meantime, the U.S. prepares for a potential policy overhaul—one that could reshape public health strategies nationwide. The conversation is far from over, and public engagement will be critical in determining the path forward.