Since fluoride’s introduction into the water supply, dental care has advanced significantly and oral care products that contain fluoride (like toothpaste and mouth rinses) have emerged, so the benefits are less pronounced, according to Dr. Deziel. But that doesn’t mean they’re not still present. Here in the US, “fluoridated products and good dental care are not affordable and accessible to everyone,” Dr. Deziel says, so water fluoridation “really is an important public health measure to address disparities in dental insurance, access to dental care, and regular dental hygiene.”
On average, US communities that have access to fluoridated water experience 25% fewer cavities, according to the CDC. To put that in perspective, providing “optimally fluoridated water” for one year saves $6.5 billion in dental treatment costs.
“Fluoridating our public water supply is really cheap to do, and it is extremely helpful for these lower income-communities to maintain good oral hygiene,” Dr. Sullivan says.
So what’s the controversy over fluoride in our drinking water?
In RFK Jr.’s post on X, he called fluoride “an industrial waste associated with arthritis, bone fractures, bone cancer, IQ loss, neurodevelopmental disorders, and thyroid disease.”
Let’s dig into some of these claims. Overall, “these statements have an element of truth, but can be misunderstood without the appropriate context or nuance,” Dr. Deziel says. First, keep in mind that the dose matters. In other words, anything can be toxic in a large enough quantity. “Water’s obviously an essential ingredient to life, but you can drink so much water that it can actually be lethal,” Dr. Sullivan points out. Similarly, “both too much and too little fluoride can create health problems,” Dr. Deziel says. Too little fluoride can cause dental issues like cavities, as we’ve already established. On the other hand, “prolonged exposure to very high levels of fluoride can actually be harmful to teeth and bones,” causing issues like bone fractures and osteoarthritis, Dr. Deziel says.
As for some of RFK Jr.’s other claims? “While studies looking at other endpoints such as bone cancer and thyroid issues exist, the current evidence base is weak and limited,” Dr. Deziel says. Besides, she adds, “Many of the health risks listed require prolonged exposure to levels much higher than those typically found in drinking water.”
What’s more, many of the studies showing a link are highly preliminary—for instance, performed in test tubes or mouse models—and suggest correlation rather than causation, according to Dr. Sullivan. Even the human studies have issues that may call their conclusions into question, like a small sample size, a very high fluoride level, or a failure to take into account factors like diet or fluorinated product use, too, Dr. Sullivan says. Others “show very modest effects, are contradicted by other studies, or have yet to be repeated by an independent group.”
Take, for instance, this 2024 meta-analysis published in Plos One. While its review of seven studies did suggest a potential link between chronic high levels of fluoride exposure and thyroid damage, the authors also caution that “every study was found to have major or minor methodological issues and significant risk of bias,” and in general, “the overall confidence in the evidence was deemed low for all outcomes.” As for the link between fluoride and children’s cognition? According to the National Toxicity Program, while high levels were associated with lower IQ in kids, there were “insufficient data” to determine if that relationship still persisted at the lower fluoride levels recommended by the CDC. While this evidence is emerging rather than conclusive—meaning we can’t yet say for certain there is any cause and effect there—it does raise questions that are worth looking into further, according to Dr. Deziel. That way, “we could still achieve the dental benefits and public health benefits, but also minimize these potential other consequences related to neurological effects.”
But on balance, the available research simply doesn’t support purging fluoride from public drinking water. Far from it, in fact. Water fluoridation “serves an important public health role,” Dr. Deziel says. “We shouldn’t eliminate fluoridation entirely, but rather examine the scientific evidence to ensure we’re targeting the correct concentrations and limits.”
The bottom line
Overall, water fluoridation has been a massive boon to public health in the US. Given its proven benefits, taking a scorched-earth approach like eliminating fluoride entirely would do far more harm than good, according to Dr. Sullivan. “We know for a fact that it is going to cause suffering and cost people a lot of money,” he says. “This is a cost-benefit ratio, and the cost of removing fluoride from the water is going to be catastrophic for dental health.”
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