The Real Science on Fluoride in Your Water

You Should Know: A new study in the Proceedings of the National Academy of Sciences found no link between fluoridated drinking water and negative impacts on brain health in 10,000 people tracked from adolescence to age 80. This addresses one of many concerns about fluoride, but is there a right amount to consume?

Going Deeper: The U.S. Public Health Service recommends 0.7 mg/L in community water, which is around average across U.S. municipal supplies (though natural groundwater can vary). The WHO’s upper guideline is 1.5 mg/L, above which dental fluorosis (cosmetic enamel changes) is common. Skeletal issues from long-term over-exposure usually appear above 3 mg/L. But cut back too much, and you won’t get the cavity protection. After all, that’s the reason there’s fluoride in your toothpaste.

Takeaway: Too much fluoride affects bone health, too little increases your chances of dental decay. Most people find the right balance in fluoridated tap water plus fluoride toothpaste. Additional supplementation could edge you over that balanced sweet spot. On well water? Test your supply.

Bottom Line: The goal should be to have enough fluoride to protect your teeth without stacking up too many sources.