Anisa Khalifa: When most Americans turn on their faucets, out comes water that contains a very small amount of fluoride. The naturally-occurring mineral has been added to the water supply in many places for decades, because of its connection to certain dental benefits. But skepticism, conspiracy theories, and outright fear of fluoridated water have been around for just about as long.
Sara Israelsen-Hartley: 鈥奿f it's really doing things to our teeth and helping them improve, like. couldn't it be doing other things to other parts of our body that we're not aware of? And maybe we haven't asked the right questions in order to identify.
Anisa Khalifa: In recent years that debate has gotten more intense as prominent skeptics have gained attention. Like recently-appointed Secretary of Health and Human Services, Robert F. Kennedy, Jr.
Robert F. Kennedy, Jr: I'm gonna give them good information about the science, I think, and fluoride will disappear.
Anisa Khalifa: So why all the confusion? Well, fluoride has continued to be controversial in part because something big has been missing 鈥�
Sara Israelsen-Hartley: We haven't had a randomized control trial, 鈥妛hich would be like a very conclusive way to show the benefits of fluoride.
Anisa Khalifa: Now, a hunt is underway for that gold standard. A study currently happening in Eastern North Carolina hopes to battle health misinformation and answer some of the longstanding questions about fluoride. All while navigating a minefield.
Sara Israelsen-Hartley: What's interesting is that a lot of the time folks that bring up concerns with fluoride are sort of labeled fringe or conspiracy theorists. And you definitely have people that fit that description who may not like fluoride. And that's where it gets a little tricky because you have people who are reputable scientists who are studying this, who are asking valid questions and trying to do valid research.
Anisa Khalifa: I鈥檓 Anisa Khalifa. This is the Broadside, where we tell stories from our home at the crossroads of the South. This week, the fight over fluoride and how challenging what we think we know might actually cool the conversation.
Okay, the first question is easy. Can you just introduce yourself?
Sara Israelsen-Hartley: Sure, my name is Sara Israelsen-Hartley, and I'm a freelance reporter working for the Assembly.
Anisa Khalifa: Sara recently dug into the science and murky politics of fluoride in a deeply reported feature for The Assembly, an online news outlet based in North Carolina. And what she found was a topic defined by contradiction.
Sara Israelsen-Hartley: What I had heard was that it seemed pretty settled. But at the same time, there鈥檚 these two very different sides. There's a definite pro side and there's a definite con side.
Anisa Khalifa: Within this fluoride debate, there鈥檚 those in favor, led by the dental health community. And those who have serious doubts.
Sara Israelsen-Hartley: That are saying, hey wait, you're going a little bit fast, like why are we adding this to the water and blanket covering an entire community.
Anisa Khalifa: And we鈥檙e talking about a lot of folks here. According to the CDC, 73 percent of people on community water systems in the United States have fluoridated water. A community water system is the public water source for a town or city鈥檚 population. In North Carolina, that percentage is even higher. About 88 percent of community water in the state contains fluoride. But why is it there in the first place?
Sara Israelsen-Hartley: Fluoride is really effective at preventing tooth decay, and so it's been added to our water because it was this very cost effective way to address cavities and reduce the amount of time that, you know, people were spending at the dentist.
Anisa Khalifa: That may sound great. But too much of a good thing can be a problem. Very high levels of fluoride can cause some pretty bad physical side effects鈥�
Sara Israelsen-Hartley: Researchers know that too much fluoride can cause staining on your teeth. If you have it at supremely high levels, it can even make your teeth turn brown, almost look like there's chocolate on your teeth. Very disconcerting. The staining of our teeth is called dental fluorosis. And they also know that if you ingest too much, like very, very high levels, it can affect your bones and joints. And so you can have skeletal fluorosis. So it'll make it sort of hard for you to have mobility.
Anisa Khalifa: And what are the recommended levels of fluoride in water?
Sara Israelsen-Hartley: So for the United States, the recommended level is 0.7 parts per million in water. So it's like a very small amount, you know, when you think about like drops in a bucket, like just a very, very small amount, but that amount is what they believe leads to this sort of protection of your teeth.
Anisa Khalifa: Once again, the recommended level in the US is nowhere near those that put people at risk for things like dental and skeletal fluorosis. But these assurances have done very little to end the debate around fluoride. And Sara says questions about its general safety have lingered for so long, in part, because research into its consumption has lacked something crucial.
Sara Israelsen-Hartley: 鈥奣he dental community for years has claimed that fluoride is safe and effective... We've seen that it's effective in stopping tooth decay. But the safe question has been sort of a little bit less unpacked, because again, we haven't had a randomized control trial of fluoride.
Anisa Khalifa: In the world of research, a randomized controlled trial is considered a gold standard. It鈥檚 setup is simple 鈥�
Sara Israelsen-Hartley: You assign two groups, you know, one of them gets an intervention and one of them doesn't.
Anisa Khalifa: And that鈥檚 exactly what鈥檚 happening right now in Kinston, a small city in eastern North Carolina.
Sara Israelsen-Hartley: So, in Kinston, Dr. Gary Slade, who's a dentist and a professor at UNC, is conducting a randomized trial of fluoride in drinking water. And he's looking at whether fluoride, in this case, bottled drinking water is going to be more effective than non fluoridated water at preventing cavities in children.
Gary Slade: 鈥妏eople just think, well we know it works. You don't do randomized trials on things that you know work, some people say. But, against that, um, it is obviously the very best evidence, and fluoridation, its where it's been criticized, for its dental health benefits because there's never been randomized study evidence to support that.
Sara Israelsen-Hartley: So there's this sort of assumption that we've already established that fluoride works. Look, it's helped our teeth. The case is closed. We don't need to do anything else. And um, that's why he's wanting to do this. He isn't quite satisfied with what, you know, evidence shows. He would like to have that extra data.
Anisa Khalifa: And what makes Kinston an ideal place to do this kind of study? Why Kinston?
Sara Israelsen-Hartley: 鈥奧ell, Kinston's unique because it's a fairly large area that doesn't already have fluoride in the drinking water. Um, the way they get their water is just from the local aquifer and it doesn't have fluoride in it or if it does, it's very, very low amounts. And so that makes it a pretty good location where you can use that as your study location and compare it to other areas that may already have fluoride.
Anisa Khalifa: Who are the participants in this study?
Sara Israelsen-Hartley: Dr. Slade is working with 200 families and children in Kinston. And these are children that are between the ages of 2 to 6 months when they were recruited, and then are going to be involved in the study until they're about four years old.
Anisa Khalifa: How long will it take for the study to be complete?
Sara Israelsen-Hartley: Many years. Probably four or five years before they have initial reports. 鈥奡o, not anything that's going to be quick, and in today's environment where people want snippets, that's just not going to happen.
Anisa Khalifa: To be clear, Dr. Slade鈥檚 study is focusing only on the dental benefits of fluoride. Nevertheless, Sara says the aim is to offer a piece of solid evidence to the fluoride debate. Something that could help reset the conversation 鈥� and encourage more rigorous and valid research.
Sara Israelsen-Hartley: I think we as humans don't always like to change our mind or maybe admit that we still have things to learn or, 鈥妕hat science changes and it requires that we shift. And we saw this in the pandemic as scientific recommendations evolved as we learned more and it was sort of hard for some people to acknowledge. That was part of the process, and instead they saw it as, I can't trust the government because the message is changing. But really, raising new questions is not a reason to panic, and it's not a reason to, like, embrace conspiracy theories. It's just an acknowledgement that science evolves. It's this process, and that as we learn more, we have to do things differently, and we may need to adjust what we've done in the past.
Anisa Khalifa: And that鈥檚 healthy. Science changes as we learn more. This new study about the dental benefits of fluoride is one step in establishing what fluoride actually does to the body. But there鈥檚 a more concerning question about fluoride 鈥� is it hurting us? That鈥檚 coming up after a quick break.
So Sara, we鈥檝e been talking about the pros and cons of fluoridated water 鈥� and this ongoing study in eastern North Carolina. But let鈥檚 go back in time for a minute. When did we first get fluoride added to our water supply?
Sara Israelsen-Hartley: 鈥奡o, the United States started putting fluoride in drinking water when they realized that it was really effective at stopping tooth decay and preventing cavities. This was back around the 1940s when they realized that a lot of tooth problems were preventing, particularly men from serving in the military.
(SOUNDBITE FROM ARCHIVAL ARMY RECRUITMENT TAPE)
Unidentified Recruiter: The job of swelling the United States Army goes full speed ahead. Recruiting offices are being set up everywhere, and there's a fine list of vacancies.
Sara Israelsen-Hartley: And that was a big problem, you know, as the US was facing war, they needed men to recruit. And if you were missing teeth, you were not eligible.
Unidentified Recruiter: The medical center is at Fort Meade, Maryland, and here the versatile soldier turns dentist, learning to extract and fill teeth, and make artificial ones. That's the only time he looks down in the mouth...
Sara Israelsen-Hartley: And so as they learned about fluoride and realized, like, this could stop all of these teeth problems and allow us to have more soldiers, they were really excited about that.
Anisa Khalifa: Fascinating that it goes back to the army. I did not expect that.
Sara Israelsen-Hartley: No and that was such an interesting tidbit to learn that that was such a key thing for the dental community to sort of latch onto is here's this really powerful solution that we think we've found. And it addresses this overwhelming problem in our community of having all of this tooth decay.
Anisa Khalifa: So when was fluoride first put into a city鈥檚 water supply?
Sara Israelsen-Hartley: So in 1945, Grand Rapids, Michigan was the first city to introduce fluoride into the community water supply. It was this big deal. They still have a monument in Grand Rapids to like celebrate this achievement. And it just just continued from there, they continued to have other cities and states join. And then, you know, they did a city in New York, Newburgh, New York, and it was really effective. Children had fewer cavities. They had like a 60 percent reduction in cavities. And, um, and so that was really exciting for the dental community to see like, okay, adding this to our water supply is really effective.
Anisa Khalifa: By the 1950s, fluoride鈥檚 popularity had extended beyond just water. It became a selling point for a new item taking dental hygiene by storm.
(SOUNDBITE FROM ARCHIVAL CREST COMMERCIAL)
Unidentified Narrator: Now after years of fluoride research, Proctor & Gamble proudly announces 鈥渢riumph over tooth decay.鈥� Available to everyone, everywhere as it brings you crest toothpaste with fluoristan.
Sara Israelsen-Hartley: You had, you know, Crest toothpaste come out in 1955. And so this is fluoride that's now, you know, topically right for your teeth, like going right on your teeth.
Unidentified Narrator: So avoid between meal treats. Visit the dentist regularly. And brush often with Crest with fluoristan. The only toothpaste recognized as effective against cavities.
Sara Israelsen-Hartley: So there was a realization that, yeah, like fluoride is really effective. And so that became sort of the mantra that fluoride is effective. This works, this is safe, this is great. 鈥夿ut there was still researchers that were along the side sort of wanting to know more and not embrace it wholeheartedly.
Anisa Khalifa: Sara says that skepticism from some researchers persisted throughout the 20th century.
Sara Israelsen-Hartley: Thinking, hey, we still should keep studying this. We might not know everything鈥�. like, what about other cells in the body? Like, is this affecting other things?
Anisa Khalifa: And in many ways, those questions have gained steam over time. Recently, a report from a federal program based in North Carolina raised alarms on another longstanding concern. Potential neurological effects on children.
Sara Israelsen-Hartley: 鈥奡o, the National Toxicology Program, which is actually based here in the Research Triangle, and they had been looking at 鈥奻luoride for a long time to try to identify this potential neurotoxic link. They did a huge review where they looked at all of the sort of studies they could find that address this topic. They reviewed a hundred studies and found with moderate confidence, and that's sort of the scientific phrase, with moderate confidence that when children were exposed to fluoride above 1.5 milligrams, or parts per million, it was linked to lower IQ.
So that as fluoride ingestion increases, IQ level drops, and this is, you know, potentially 1 point, 2 points, 3 points, 4 points, not something that you would notice on an individual level, but at a population level that's concerning for scientists. That's still an open question. We're still learning more about that.
Anisa Khalifa: And just to say it again 鈥� the recommended level in the US is 0.7 milligrams.
Sara Israelsen-Hartley: So they found that there's a correlation that as your fluoride intake goes up, your IQ goes down. 鈥夾nd they could not comment specifically on whether that was happening at the level in our current water. And that's sort of what this all hinges around, is people want to really fixate on, well, what's happening now? Like, in the water I'm drinking, is this affecting my brain, my children's brain? The tricky question right now is that the research doesn't say cannot conclude that the fluoridated water we're drinking now has this impact. It's for water that has higher levels of fluoride.
Anisa Khalifa: Yeah. I mean, so the levels they're talking about are more than twice the amount that we have in our water currently, or that is recommended for our water currently. But then there's also the question of we're getting fluoride in other ways too, right? So do the studies address that as well?
Sara Israelsen-Hartley: 鈥奣he studies point that out that we're not just getting fluoride from our water, we're getting it from our toothpaste, mouth rinses, from the foods we eat. Black tea in particular has very high levels of fluoride just because the plant absorbs it from the soil as it grows. You know, things like grapes are getting, you know, often pesticides have fluoride in them. 鈥奡o their concern is that if the dental community fixates on this sort of 0.7 number, as you haven't proven this is a problem yet, they're saying, but wait, that's just one part of the equation. What about fluoride coming from all of these other sources? We're getting too much.
Anisa Khalifa: These ongoing questions about fluoride bring us back to Kinston, North Carolina, where Dr. Slade is conducting his multi-year study on the dental benefits of the mineral. Sara says that Dr. Slade knew there would be some concerns over his research. So he spent the first year building trust 鈥� talking with people in the area, giving tours of their bottling facility, and hosting community forums.
Sara Israelsen-Hartley: In this community forum, you know, he spoke and answered questions. There was also Stuart Cooper, who's the executive director of the Fluoride Action Network, which is opposed to fluoride being added to community water supplies.
Stuart Cooper: 鈥奧hat the Fluoride Action Network does not oppose is the use of fluoride toothpaste or fluoride in mouthwashes or other dental products.
Anisa Khalifa: This is Stuart Cooper, FAN鈥檚 executive director, during a recent conversation with Sara.
Stuart Cooper: We simply oppose ingestion fluoride and especially water fluoridation. 鈥奧e try to alert the public to fluoride toxicity or situations where they'll be overexposed.
Sara Israelsen-Hartley: He expressed his concerns and told community members that he believed they weren't getting the full information, that they weren't being told about these neurotoxic effects on their children. 鈥夾nd in speaking with the health director, that was sort of upsetting to her because she felt like it was coming from a place of fear mongering and trying to be really frightening to parents who were being recruited to the study.
Anisa Khalifa: 鈥奡o is this randomized control trial going to be the silver bullet that, you know, fixes the fluoride controversy and answers everyone's questions for good?
Sara Israelsen-Hartley: You know, you want to say yes, but no, it won't be, because as we said before, this is an emotional issue. This is really contentious. And unfortunately, facts are not always the way that people change their mind, as ironic as that sounds. I think this will be effective in offering a piece of evidence that fluoride is effective in this way. But this study is limited in what it can say. This study can only comment on the effectiveness at reducing cavities for children. This study can't say anything about IQ. It can't say anything about neurotoxic effects. That's not how it was designed. That's not the data they're collecting. So in terms of it, like, settling the debate? No. It won't settle the debate. It will add a layer to the scientific knowledge.
Anisa Khalifa: Dr. Slade's research will continue for a few years before he can draw any conclusions. In the meantime, Sara says the debate about fluoride isn't going anywhere 鈥� but what's gonna matter most is how we choose to hash it out.
Sara Israelsen-Hartley: I have come away from this story, um, with just an additional layer of nuance that very, very few things are binary where this is good and bad. This is sort of a yes and both things sort of exist together. Fluoride is really good for our teeth. Fluoride may also be problematic for our brains. We don't know enough to fully embrace or fully exclude. What's interesting is that a lot of the time folks that bring up concerns with fluoride are sort of labeled fringe or conspiracy theorists. And you definitely have people that fit that description who may not like fluoride.
And that's where it gets a little tricky because you have people who are reputable scientists who are studying this, who are asking valid questions and trying to do valid research. And then you also have groups that are maybe leaning a little bit more heavily on like the public liberty or my freedom and justice angle and don't like it added for those reasons. And so there's people that, they come from different places, but they often all get lumped together. It's just, you're, you're opposed to fluoride, therefore you must be a conspiracy theorist or you must believe all these other false public health things. And I don't think that's entirely fair or true.
Anisa Khalifa: Thank you so much for talking with me.
Sara Israelsen-Hartley: So glad to be here.
Anisa Khalifa: This episode of The Broadside was a co-production with The Assembly. If you鈥檇 like to read Sara Israelsen-Hartley鈥檚 article about fluoride at their website, we鈥檝e dropped a link in the show notes. Charlie Shelton-Ormond is our producer. Jerad Walker is our editor. Our executive producer is Wilson Sayre. The Broadside is a production of 瓜神app鈥揘orth Carolina Public Radio and is part of the NPR Network. If you have feedback or a story idea, you can email us at broadside@wunc.org. If you enjoyed the show, leave us a rating, a review, or share it with a friend! I鈥檓 Anisa Khalifa. Thanks for listening y'all. We'll be back next week.