Fluoride in Drinking Water: Safe at Low Levels, But the Debate Continues

The debate around fluoride in public water supplies has resurfaced after Health and Human Services Secretary Robert F. Kennedy Jr. proposed a nationwide ban on fluoridation. Citing concerns about potential neurotoxic effects in children, Kennedy’s proposal comes amidst growing global scrutiny over fluoride exposure. While his stance has raised questions and reignited concerns, most health experts continue to support fluoridated water at current U.S. levels, pointing to decades of evidence demonstrating its role in promoting dental health.

Fluoride, a naturally occurring mineral, has been added to public water systems in the United States since the mid-1940s to reduce tooth decay, especially in communities with limited access to dental care. Currently, the recommended level of fluoride in drinking water stands at 0.7 milligrams per litre, according to the Centres for Disease Control and Prevention (CDC). This level, experts say, balances the dental benefits of fluoride with the risk of side effects like dental fluorosis.

Kennedy’s call for a ban follows Utah’s recent decision to become the first U.S. state to prohibit fluoride in public water supplies. In parallel, the Environmental Protection Agency (EPA) has committed to reviewing new scientific findings related to fluoride safety, signalling potential shifts in future policy.

Though Kennedy cannot enforce a federal ban on fluoride in water, he can influence public health guidelines through agencies like the CDC or push for the EPA to adjust the maximum allowed levels. His position is partly fuelled by recent studies suggesting that high fluoride exposure may be linked to lower IQ levels in children, particularly in non-U.S. countries with elevated fluoride levels.

A recent study published in JAMA Paediatrics found an association between high fluoride levels and diminished IQ scores in children from countries like China and India, where water fluoride levels often exceed international guidelines. However, experts caution against extrapolating those findings to the U.S. context.

Dr. Danelle Fisher, a paediatrician based in California, emphasised the importance of keeping public reaction grounded in facts. “We need to reassure people that the current fluoride levels in U.S. water are safe,” she said. “Children benefit from correctly fluoridated water, especially when combined with fluoridated toothpaste.”

Other experts agree, underscoring the distinction between systemic exposure (like drinking fluoridated water) and localised use (like brushing with fluoride toothpaste). Dr. Inderpal Randhawa, a paediatric pulmonologist, acknowledged potential health concerns tied to long-term fluoride exposure, including effects on the thyroid, bones, and other organs. However, he noted that fluoridation might still be beneficial in areas with limited access to dental services.

Despite these reassurances, the body of research on fluoride is far from conclusive. Critics like Dr. Bruce Lanphear of Simon Fraser University argue that the evidence supporting the safety and effectiveness of fluoridated water isn’t as robust as once believed. Lanphear co-authored an editorial accompanying the JAMA Paediatrics study and advocates for removing fluoride from drinking water, citing possible neurodevelopmental risks and insufficient modern research supporting systemic fluoridation.

He points to a 2024 Cochrane Review that found only modest benefits of water fluoridation on reducing cavities—suggesting a potential reduction of only a few percent. “The evidence about the effectiveness of water fluoridation has never been particularly rigorous,” Lanphear said. “And now we’re seeing potential harms.”

Dental fluorosis—white or brown staining on teeth caused by excessive fluoride—has become more common in U.S. children over recent decades, prompting health agencies to lower the recommended fluoride level in water from 1.2 mg/L to the current 0.7 mg/L. While fluorosis is largely cosmetic, its increasing prevalence has added to concerns about overexposure.

Yet, the potential risks must be weighed against the historical benefits. Before fluoridation became widespread, dental decay was rampant in children, often leading to serious infections and complications. “We’ve seen what happens without fluoride,” Dr. Fisher said. “Dental problems don’t just stop at the mouth. They can affect the whole body and even cause life-threatening infections.”

Dr. Randhawa echoed the need for context, advocating for a more nuanced approach. In areas with high-quality dental infrastructure and regular access to fluoride-based products, water fluoridation might be unnecessary. In underserved communities, however, fluoridated water remains a vital public health tool.

Ultimately, both sides of the fluoride debate agree on one thing: more research is needed. Experts are calling for long-term studies conducted in the U.S. that evaluate fluoride exposure levels and their potential impacts on children’s health—including cognitive development. Dr. Fisher urged for future research that’s specific to American populations and not based solely on international data.

“If we find out that the current fluoride levels are too high or too low, we can make adjustments,” she said. “But right now, the existing levels are considered safe and beneficial.”

As public health officials, researchers, and concerned citizens continue to examine fluoride’s role in water systems, it’s clear that a balanced, science-driven approach is essential. Panic or misinformation, experts warn, could undermine decades of progress in public dental health.

“Fluoride is not something to be feared when used appropriately,” Dr. Fisher concluded. “We need to stay informed, support high-quality research, and do what’s best for our children—both for their teeth and their overall well-being.”