The Current - What the science says about fluoride in drinking water

Episode Date: January 30, 2025

Montreal is removing fluoride from drinking water, while Calgary is putting it back after a pause of more than a decade. We look at what the science says — and the direct influence of Robert F. Kennedy Jr., who got into heated exchanges at his confirmation hearing to become U.S. health secretary on Wednesday.

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This is a CBC Podcast. Hello, I'm Matt Galloway and this is The Current Podcast. I think fluoride is a poison and it causes cancers. Of course, it causes your bones to deteriorate. That's Robert F. Kennedy Jr. U S president Donald Trump's nominee for health secretary. Today is day two of his confirmation hearing.

Day one got off to a fiery start in a moment. We will hear more about RFK Jr.'s plans to, in his words, make America healthy again and the pushback to those plans. But first among his many areas of focus is his position on fluoride. It goes against the scientific consensus on the issue here in Canada. The Canadian dental association says that

adding fluoride to the public water system in order to prevent tooth decay is quote safe, effective and economical. And yet some cities are taking that mineral out of drinking water. In Montreal, a recent petition from Ray Coelho says that the, uh, he has support of RFK Jr. and it ended with city officials deciding to end fluoridation in the West Island in Montreal.

The people have spoken through the petition and I think the city of Montreal did a responsible act in ending fluoridation. I think it's on its way out. It's an archaic practice. That's in Montreal. Meanwhile, in Calgary, fluoride is on the way back. Officials there took it out of the water supply in 2011. Now that city says it will be back in the water by the end of March. Lindsay McLaren studied what happened to the dental health in Calgary in the years without fluoride. She's professor of community health sciences at the University of Calgary. Lindsay, good morning. Good morning.

Tell me about your research. How did you look into what happened when fluoride was removed from the water in Calgary? So it all started back in 2011, as you noted, when Calgary City Council voted unilaterally to stop adding fluoride to our drinking water here when Calgary City Council voted unilaterally to stop adding fluoride to our drinking water here in Calgary. And that provided an opportunity to build a study

around that policy decision. And I just want to fit in here that it's important to kind of note that this is what this kind of research looks like in public health. So we're not talking about clinical or lab-based research in public health. We're talking about large-scale population level policy. So we designed a study that was built around this decision to stop adding fluoride to the water. What were the results and how conclusive were those results? Yeah, sure. So the study involved collecting data on dental health or dental caries or tooth decay

from a large sample of children in both Calgary where fluoridation had been of children in both Calgary where fluoridation had been stopped and in Edmonton where fluoridation remained in place. And so we compared those two samples of children and over the course of two follow-up studies, one about three years after fluoride had been removed and the other about eight years after fluoride had been removed, we saw significantly higher levels of cavities in the Calgary kids compared to the Edmonton kids. How do we know that it's fluoride in the water that was making the difference when it comes to what you saw in Edmonton versus Calgary?

Yeah, that's a really important question. So again, going back to my comment about the nature of this kind of research, it's not the type of this kind of what else could be explaining the different rates of cavities and try to account for those factors or to measure them. And so we took a number of steps to try to do that. So in addition to ascertaining the different levels of fluoride in the water in the two cities from the municipal water reports, we also had a questionnaire that the kids' parents completed

and that questionnaire gathered data on many different factors that are known to be related to dental caries. So socioeconomic factors, behavioral factors, dietary factors like sugary drink consumption, as well as things like other sources of fluoride, so use of fluoride toothpaste, fluoride at the dentist, whether they usually drink tap water at home versus some other source, their residential history, etc. So we were able to to to examine those factors between the two cities and take those into account in in the analysis. And then the third component was for a small random subsample in each city, we took fingernail clippings, which are a biomarker of fluoride intake.

And this is important because kids in Calgary should have less fluoride based on those biomarkers than kids in Edmonton. And if that was not the case, then the whole question would become moot. So we were able to ascertain using... So for example, sometimes, you know, some people, knowing that there's no more fluoride in the water, might make changes to sort of compensate for that. Like they might try to get fluoride from other sources or dental health professionals might kind of adjust for that situation, but the biomarkers allowed us to see that that wasn't happening to any significant extent.

I mean, in part, that's important because in Montreal, the executive committee member who's responsible for water says that there's widespread use of fluoridated toothpaste now, so you don't need fluoride in the water. What do you make of that? Yeah, so that's an important point as well. And indeed, fluoride toothpaste is an important source of fluoride for many people. In fact, you really have to go out of your way to buy toothpaste without fluoride now. So fluoride toothpaste has been widespread since about the 1970s.

And, uh, and we still see an effect of fluoridated water on dental caries, even in this sort of fluoride toothpaste era. So above and beyond, it's less, it's less, but it's still there. Can I ask you about the safety issues? We heard earlier that clip from RFK Jr. He's talking about fluoride causing cancer and causing your bones to deteriorate. How safe is fluoride? Yeah, so fluoride at the levels that are considered optimal for drinking water are safe. So I'm aware of studies that have concluded otherwise, but I think the really important issue

here is the level of fluoride that's being discussed. And at the levels that are recommended optimal for community water fluoridation, I don't believe there's robust evidence that there are water fluoridation, I don't believe there's robust evidence that there are harms. That's in fact built into what is the optimal recommended concentration in drinking water. That's not a willy-nilly arbitrary level. A great deal of work goes into identifying a level that is that balances effectiveness and safety and it errs on the conservative side. He also talked about this, what he believes is a link between fluoridation and lower IQ and referenced a recent study that linked the two.

What does the science say about that? And what did the broader scientific community think of that study? Mm-hmm. So that's really the health concern that I was referring to in my comments just now is this recent work around neurodevelopment and cognition. And as I say, I don't believe that there's robust indication that there are harms at the level recommended for water fluoridation. When you've talked about this, you yourself have been targeted by anti-fluoride activists

as a result of your research. You've been called a fraud, you've been called a fanatic. What do you make of the aggression, and this is your word, the aggression that has been directed your way? Mm-hmm, mm-hmm. Well, it certainly, I hadn't experienced that before in other areas of health, so it certainly, yeah, was something to experience. I mean, you know, people, some people feel strongly about this issue. To some extent, I about this issue.

To some extent, I think this comes with the territory in public health because of our focus at the population level, we're frequently talking about policies or interventions that apply to a large number of people. And inevitably there are going to be some individuals that disagree with it. But we have to have that aspect of health in order to ensure our societal wellbeing.

We simply can't ensure health and wellbeing of the population as a whole through individualized clinical intervention. That's only one part of the story. Lindsay, we'll leave it there. It's good to speak with you. Thank you very much about this. Thanks for having me. Lindsay McLaren is a professor of community health sciences at the University of Calgary talking about the reintroduction of fluoride to the drinking water in that city. Hey there, I'm David Common. If you're like me, there are things you love

about living in the GTA and things that drive you absolutely crazy. Every day on This Is Toronto, we connect you to what matters most about life in the GTA, the news you gotta know, and the conversations your friends will be talking about. Whether you listen on a run through your neighbourhood or while sitting in the parking lot that is the 401

Check out this is Toronto wherever you get your podcasts I Support the measles vaccine I support the polio vaccine. I will do nothing as HHS secretary And makes it difficult or discourages people from taking either of those. Anybody who believes that ought to look at the measles book you wrote saying parents have been misled into believing that measles is a deadly disease. That's not true. It's just one of the many contentious back and forths between senators and Robert F.

Kennedy Jr. at his confirmation hearing yesterday. Democratic senators pushed Kennedy on his statements on health issues including vaccines, many of which scientists say are false or misleading. Laura Helmuth is a freelance science writer, former editor-in-chief of Scientific American. She's a contributor to Slate. She's in a studio in Washington, D.C. this morning. Laura, good morning to you. Good morning, thanks for having me.

Thanks for being here. That was just one of the heated exchanges that we saw yesterday. That was between Democratic Senator Ron Wyden and RFK Jr. We'll get to his specific beliefs in a moment, but how broadly, if you take a look at the bigger picture, how did his confirmation go yesterday? Yeah, it was very dramatic. A lot of spicy exchanges.

I think it's clear that throughout the hearing, which lasted three and a half hours, he repeatedly said things, as in the clip that you just shared, that directly and dramatically contradict 20 to 30 years worth of writings, podcasts, book publishing. It's clear he was lying throughout the hearing. He would be in control of what? A department that has a 1.8 trillion dollar budget? Yes, it's a huge department and it oversees 80,000 employees. So they're in charge of federal insurance programs, food safety, disease tracking, and basically all biomedical research that's supported by the US government. Let's talk about some of his specific beliefs. He said in that clip that we heard that he

supports the measles and polio vaccines. He wouldn't do anything to discourage people from taking those vaccines. What has he said in the past about vaccines? Yeah, completely the opposite. So he has a history of comparing vaccine research and vaccine distribution to the Holocaust, to Nazi things. He's compared the Centers for Disease Control and Prevention to Nazi death camps.

Yesterday he was asked about that and he denied it until a transcript was produced saying that he had said just that. Yeah, which it's interesting. He's willing to lie about what he said in the past even though everything is easily demonstrable based on things that has been recorded saying. So it just shows his whole campaign against vaccines

and for what he calls alternative health. It's just based on lies and whatever he'll say in the moment and he'll make up data and show charts and be very, very passionate and very confident. And so it sounds like he knows what he's talking about, but it just doesn't fit any of the facts or any of the past evidence based on what he said in the past.

Let me understand that. What do you make of what he was trying to do yesterday in walking back some of the vaccine skepticism, if you want to call it that, despite the fact that in the room, I mean, there are supporters of the things that he has said in past. Yeah, it's really fascinating.

And he's made some very dramatic pivots, even just in the past few months. When he was running for president himself, of course, he said, even before then, said very negative things about President Trump. But now that he's been nominated to be part of Trump's administration, he's claimed that he was brainwashed and he's gone full MAGA, full Make America Great Again, and has completely just changed his tune on all the things that he's really devoted his career to.

So it's fascinating to see just how flexible he is in what he's willing to say on the record. We were just talking about fluoride in this petition in the city of Montreal to remove fluoride from the water and the belief that that petition in many ways was influenced by Robert F. Kennedy Jr. What sort of influence has he had on that issue of fluoride? Yeah, I think with fluoride and of course with every bit of influence he's had, it all starts with his name because he's so famous and his name has such respect in the United States and around the world. And so he's used that to sort of amplify older conspiracy theorists or conspiracy theories.

And the campaign against fluoride started with like the John Bircher Society. It's been around for decades. And it's kind of part of this idea that the government is conspiring to control people's minds to put microchips in them. It's all part of kind of an anti-government, anti-health, anti-establishment, really dramatic set of conspiracies that there's obviously no basis for whatsoever, but it makes a very dramatic story. What do you make of the constituency that follows him, that believes him, the people who think that he's right, that he's speaking truth to power

Yeah, it's interesting. He had a fairly small constituency starting out Which was again basically just because of his name people thought he must know what he's talking about because he's a Kennedy When it when it started I think some of the first people who supported him and were very nervous about vaccines Kind of come from a more of a left-wing, kind of a natural back to nature, not trusting modern medicine, being more interested in kind of alternative health. I think his, some of his claims resonated with that audience. But now he's gone fully in the other direction. And the people who are more interested in him now and that we saw in the hearings yesterday are very libertarian

people who think the government shouldn't have anything to do with children with how people run their families with any directives about what kind of vaccines people should have or or how we should handle pandemics or interact with the rest of the world about public health. I want to talk about one more thing that he was pressed on yesterday and this is the issue of antidepressants. Here's a back and forth he had with the Democratic Senator Tina Smith. So do you believe as you've said that antidepressants cause school shootings? This should be a simple question. I don't think anybody can answer that question and I didn't answer that question. I said it should be studied along with other potential culprits because there's no science

on that. I said it should be studied along with other potential culprits because there's no science on that. The science shows that there is no link between school shootings and antidepressants. And in fact, most school shooters were not even treated with antidepressants. And of those that were, there was no evidence of association. What do we know about his thoughts on antidepressants? Yeah, this is kind of part of his whole kind of anti-medicine, anti-science, making up facts to fit his worldview approach to things.

Yeah, he's been very against antidepressants. He's cast doubt on whether HIV causes AIDS. He's claimed that various health interventions cause cancer. He really is just willing to say anything negative about any sort of modern medicine that you know and this all kind of fits into his idea that you know natural is better and that humans shouldn't be treated by modern science. He's also expressed views and has broader support perhaps for the way that he has proposed tackling the issue of processed foods, reducing the power of big pharma, looking at

chronic disease. Even someone like Bernie Sanders has said, in Bernie Sanders' words, RFK Jr. is exactly correct on the food issues. What do you make of that? I mean, is there the possibility that he's right on these things? Yeah, I think he's not as wrong on these things.

There definitely is a lot of kind of new evidence and new awareness of the danger of processed foods, meaning foods that have very little fiber, very little nutrition relative to the fat and calories that are in them. So he's not necessarily wrong about that. But the problem is that he's saying that food can cure illnesses that can be prevented or cured by actual medicine. So he's claimed that chicken soup can cure measles and of course chicken soup is lovely. If you're sick, it does make you feel better. Chicken soup is a perfectly good food. It's very nutritious, but it's not a substitute

for vaccines. It's not a substitute for chemotherapy for people who have cancer. And so by kind of directing everybody's attention and claiming that food can cure all ills, it basically draws people away from actual medicine and actual treatments and preventions. We're out of time, but just very briefly, it has been said that if he were confirmed, he would be the first skeptic of science to be responsible for safeguarding public health.

What's at stake here? You mentioned the idea of pandemics. There is concern about bird flu that could be spreading. Yeah, there's never been a more important time to have people who are in charge of public health, who understand science, who recognize that pandemics are global, that what happens on a chicken farm in California can spread throughout the world very quickly. And we need people who can trust the experts, trust data, share meaningful information,

and help people understand what the risks are and to protect themselves. And it's just incredibly dangerous to have someone who's a demagogue, who's sharing misinformation, propaganda, disinformation, at a time when public health has never been more crucial. Laura, we'll leave it there. Thank you very much.

Thank you. Laura Helmuth is a freelance science writer, contributor to Slate Magazine. She was in our studio in Washington, D.C.