An article published in early 2014 in the medical journal Lancet Neurology generated a lot of attention when it concluded that fluoride—used in toothpaste and added to the public water supply in most of the U.S. to help prevent dental cavities—may impair brain development in children. But is this the case? And is there any merit to other scary claims made online about fluoride contributing to cancer and other problems? Before you swear off fluoride toothpaste and tap water, read our answers to four key questions about this misunderstood chemical.
How good is the research on the risks of fluoride and kids?
Not good. In fact, the new Lancet article presented no new data: It simply reiterated the findings of a systematic review published in 2012 that caused a stir on social media. That review was predominantly based on old data collected in China, where some rural areas have high concentrations of naturally occurring fluoride in their drinking water. (Those levels are substantially higher than the ones added to public water supplies in the U.S.) The data showed that children living in areas with the highest fluoride levels tended to have lower IQs than children who may have received less exposure—that is, they lived in areas where the drinking water had lower concentrations of fluoride.
But such a study can’t establish cause and effect; it can only show an association. So it’s not clear whether it was fluoride that contributed to the children’s neurodevelopmental problems, or other factors (for example, other chemicals in the water supply, or poor nutrition). And other studies have shown no neurodevelopmental delay in children who have fluoride in their drinking water when compared with those who do not.
In contrast, there’s a strong body of well-designed studies that show fluoride improves dental health in kids as well as adults. That’s why a small amount of fluoride has been added to many communities’ public water supplies since the 1940s, during which time the incidence of tooth decay has dropped significantly.
Do I need to limit my kids' exposure to fluoride—for example, by buying fluoride-free toothpaste?
We don’t think so. In fact, it might backfire: Your kids need a small amount of fluoride in order to avoid tooth decay and cavities. As long as you ensure your children don’t swallow large amounts of toothpaste or mouth rinses, fluoride toxicity is very unlikely. Have them swish and spit. For best results, adults and children alike should brush twice a day, using a soft-bristled toothbrush and employing proper toothbrushing technique.
Can fluoride cause cancer, as some websites claim?
Good science does not support this claim. Some anti-fluoride groups have cited a few studies that seemed to show a link between fluoride exposure and osteosarcoma, a type of bone cancer, and certain other cancers. But those studies were either poorly designed or refer to animal data.
Medical and scientific organizations including the National Institutes of Health, the American Academy of Pediatrics, the National Academy of Sciences, and the American Council of Science and Health all have concluded (based on a thorough literature review and on large population-based studies) that there is no sound basis for the claim that fluoride causes cancer. The U.S. Centers for Disease Control and Prevention has included fluoridation of drinking water among the 10 great public health achievements of the twentieth century.
What about fluorosis—those white spots you can get on your teeth from too much fluoride? Are they dangerous?
No, and the condition is uncommon. Fewer than 3 percent of children develop fluorosis that’s significant enough to cause white spots on the teeth. Even then, it’s solely a cosmetic problem. You can help prevent it by making sure your children don’t eat, swallow, or otherwise overuse toothpaste and mouth rinses. There is also no need to take supplemental fluoride tablets or drops unless your dentist recommends them.
Bottom line: Fluoride is an inexpensive, safe and easy way to protect your oral health. So brush your teeth and stay well!