Fluoridating the public water supply has been common practice for nearly 80 years in the U.S. It's an acclaimed public health intervention that helps prevent cavities. For just as long, some have raised concerns about the practice that can veer from evidence-based to unsubstantiated conspiracy. An analysis by government researchers, published Monday in JAMA Pediatrics, is adding to the debate. The research found that exposing babies and kids to high levels of fluoride might be associated with neurodevelopmental harm. Frankly, it's a lot to digest — so we invited health correspondent Pien Huang onto the show to wade through the debate.Questions, story ideas or want us to dig into another public health debate? Email us at [email protected] — we'd love to hear from you! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy
What is fluoride and why is it added to drinking water?
It also naturally occurs in all kinds of foods like spinach and seafood and tea and fruit. You'll find fluoride there.
The science is clear, Emily. Fluoridating water lowers the numbers of cavities in people, which it does by restoring minerals to teeth that are lost when bacteria grow inside the mouth, especially after, like, say, drinking sugary drinks. And this is especially useful for lower-income families who might not have access to fluoride products like toothpastes and mouth rinses.
There's a study by the Colorado School of Public Health which found that adding fluoride to the water saved around $6.8 billion in dental expenses in one year alone.
So this has been the story of fluoride for most of our lifetimes. It's a very rosy public health story. But it sounds like there's always been a little bit of pushback. Tell me about that.
Yeah. So ever since it started, there's been this debate over fluoridating water. Our colleagues Jeff Brumfield and Selena Simmons-Duffin have reported about conspiracy theories surrounding fluoride in drinking water. There was this time in the 1960s when the John Birch Society, this far-right group, alleged that it was part of a communist plot.
And there are lots of other theories around it as well, different versions that reflected the concerns of their times. But meanwhile, the scientific understanding is also evolving, which brings us to this latest research in JAMA Pediatrics. It was done by government scientists at the National Toxicology Program. That's the part of the NIH that you mentioned earlier. Uh-huh, with that August report.
That's the one. And like we were saying, they just published a study in JAMA Pediatrics that looks at a few dozen studies that other people have conducted. And it finds this link between high levels of fluoride and a small decrease in children's IQ. Now, it's not totally definitive. This is something that they're saying with moderate confidence.
Okay. We could have a whole aside about IQ tests and what they measure. Sticking with the study, what does moderate confidence mean?
So moderate confidence is basically like a grade that they put on the quality of evidence that's available to them. It's not low quality. It's not high quality. It's enough to say something with moderate confidence. Does that make sense?
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