Fluoridation nation
Ever since fluoridation became widespread in the 1950s, cavities in kids have fallen drastically. The effort is considered one of the ten greatest public health achievements of the 20th century. But it’s also one of the most controversial.
At really high doses, fluoride is toxic – it can calcify your ligaments and joints and even fuse your spine. It also potentially has impacts on our brains. There’s a small but growing body of research suggesting that fluoride can inhibit intelligence in children.
This is still unsettled and hotly debated science but, as host Nate Hegyi finds out, in our polarized and increasingly digital world… unsettled science can quickly become doctrine.
Featuring Rene Najera, Philippe Grandjean and Mark Hartzler
ADDITIONAL MATERIALS
The CDC has a website that tells you how much fluoride is in your drinking water.
Here’s the reasoning behind the U.S. Public Health Service’s recommended limit for artificially fluoridating water.
The National Toxicology Program suggests that a child’s IQ could be impacted if they or their pregnant mother ingests more than 1.5 ppm of fluoride in their water.
Philippe Grandjean’s peer-reviewed study suggests that the safe level of fluoride in water for pregnant women is much lower than what the U.S. Public Health Service recommends.
The American Academy of Pediatrics and the American Dental Association have cast doubt on the National Toxicology Program’s conclusions and say that the fluoride levels in U.S. waters are safe.
A U.S. district court judge ordered the Environmental Protection Agency to take a second look at its limits for fluoride in the water, citing the National Toxicology Program’s monograph.
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CREDITS
Host: Nate Hegyi
Reported, produced and mixed by Nate Hegyi
Editing by Taylor Quimby, with help from Rebecca Lavoie
Our staff includes Justine Paradis, Felix Poon, Kate Dario and Marina Henke
Executive producer: Taylor Quimby
Rebecca Lavoie is NHPR’s Director of On-Demand Audio
Music by Blue Dot Sessions.
Our theme music is by Breakmaster Cylinder.
Outside/In is a production of New Hampshire Public Radio
Audio Transcript
Note: Episodes of Outside/In are made as pieces of audio, and some context and nuance may be lost on the page. Transcripts are generated using a combination of speech recognition software and human transcribers, and may contain errors.
Nate Hegyi: You’re listening to Outside/In… I’m Nate Hegyi. Let’s go back in time to the year 1901. The man? A young dentist named Frederick McKay… He had just arrived in a small frontier town called Colorado Springs. As soon as he got there… he noticed something strange.
MUX: Sneak in Desjardins - The Maison
Nate Hegyi: The townspeople who became his dental patients had dark brown spots all over their teeth. We’re talking the color of chocolate.
Rene Najera: But interestingly he noticed that they didn't have cavities.
Nate Hegyi: Brown teeth. Few cavities. That by the way is Rene Najara. He’s an epidemiologist and director of public health at the College of Physicians of Philadelphia. He says Frederick McKay noticed this was a regional thing.
Rene Najera: In other towns kids had teeth that were normal for the time, with plenty of cavities but they were nice and white teeth.
Nate Hegyi: The condition was nicknamed Colorado Brown Stain. Locals blamed the phenomenon on a number of things. Eating too much pork… drinking funky milk. Or maybe… there was something in the water.
MUX: Desjardins - The Maison peak and fade
Nate Hegyi: That last theory had legs. There was another town in Idaho that also had Colorado Brown Stain. But when they switched to a different water source… it went away. Then there was this mining town in Arkansas. They also had cases of Colorado Brown Stain. Yet a town five miles away… didn’t. So an employee for the mine collected water samples from the town and sent them to the company lab.
Rene Najera: and the guy at the lab is like, you contaminated the sample. It has way too much fluoride in it. And send me another one. And so they sent another one. And they they come to the conclusion that the water in, in some towns had a lot of fluoride in it and the water and others did not. And that correlated with the staining of the teeth.
MUX: The Maison (Toplight)
Nate Hegyi: Fluoride. You may be under the impression that fluoride is a chemical we ADD to water. And that’s true. But it’s also found in nature. The people in these towns weren’t putting fluoride in the water. It was already there.
Rene Najera: You're going to find it in groundwater, specifically in places that have a lot of volcanic or used to have a lot of volcanic activity.
Nate Hegyi: But this discovery led to the birth of one of the largest public health initiatives in American history. An effort to save our children’s teeth by tinkering with community water supplies all across the country. It’s a move that’s been as successful as it is controversial.
Montage: “Fluoride is safe and effective.”
Joe Rogan: ‘Fluoride is a neurotoxin’
YouTube clip: “It’s good in small doses.”
RFK Jr: I think fluoride is a poison
MUX: The Maison BUMP
Nate Hegyi: Today on the show… What is the deal with fluoride? Sure, it has saved millions of mouths, and billions of dollars in dental bills. But… as they say in Marathon Man:
Lawrence Oliver: Is it safe? Is it safe? Is it Safe?
Nate Hegyi: Stay tuned.
MUX: The Maison BUMP and fade
Nate Hegyi: [in tape] North country dental… there it is…
Nate Hegyi: I figure any good story involving teeth should begin with a dentist.
Dental Assistant: C’mon in, Dr. Hartzler is waiting for you
Nate Hegyi: [in tape] okay, great, awesome
Nate Hegyi: In this case… Dr. Mark Hartzler. He has a practice in the small town of Gorham, New Hampshire.
Nate Hegyi: [in tape] Nice to meet you, sorry about the cold hands!
Nate Hegyi: A big part of Mark’s day is spent finding and fixing cavities.
Nate Hegyi: [in tape] we've all had cavities, or most of us at least have had cavities. Have you had a cavity, actually?
Mark Hartzler: Oh, yeah. You can come from a dental family and still get them. It it happens.
Nate Hegyi: These are essentially holes in the enamel of your tooth. For thousands of years - people were convinced they were caused by worms, burrowing into our teeth the way they might burrow into an apple. The truth is not as gross.
Mark Hartzler: think of a tooth like an M&M. You've got the outer, the thinner outer layer. That's a little harder than the bulk of the M&M inside which is chocolate right. So in a tooth the outer layer is called enamel. The inner layer is called dentin. And there is more dentin than there is enamel. But the enamel the outer layer is typically more more hardened and calcified. So that provides a little bit more protection in the oral cavity. Um, as we eat various foods, um, things with sugars, sucrose, glucose, anything like that. The bacteria that are normally in our mouths will break those sugars down themselves and secrete acid. Acid then starts to, um, eat away at the outer enamel of teeth. Eventually that process continues for a while and and you end up with a cavity or a hole that's now formed there.
Nate Hegyi: Cavities aren’t just a pain. If left untreated… they become an open door for bacterial infections:
Mark Hartzler: So bacteria can spread down into the jawbone itself and into the blood supply from there. And So a common concern for people with, say, artificial heart valves is that oral bacteria can get into the bloodstream and have and cause issues with their artificial heart valves.
Nate Hegyi: There have been multiple studies that show the more teeth you lose because of decay…. The shorter your lifespan is. This is why keeping your mouth healthy and cavity free is so important. And we have lots of ways to do that. We get cleanings every six months or maybe fillings when we need them. But these are all relatively new treatments. Dentistry as we know it has only been around for a hundred, 150 years.
MUX - Crumbtown BUMP
Nate Hegyi: For a lot of human history, the solution to a tooth ache was… just get rid of the tooth. You’d go down to your local barber or blacksmith and they would yank it out. Seriously. And after the industrial revolution, when sugary and processed foods got really popular, this happened a lot. Fun fact: the failure to meet a minimum standard of having six opposing teeth was the leading cause of rejection of people who signed up for military service in both world wars. So for many decades, our mouths weren’t great.
MUX: Crumbtown Pop and Fade
Nate Hegyi: This is why, in the early 1900s, dentists were so intrigued with the discovery that ingesting fluoride was sure - turning teeth brown - but also making those teeth resistant to cavities. But how? For the answer, we’re going to need a little chemistry lesson.
MUX: Beignet Interlude
Nate Hegyi: The enamel in our teeth, so the hard outer stuff, is made of a mineral called Hydroxyapatite.
Mark Hartzler: Hydroxyapatite is made up of calcium phosphate and a hydroxyl group. Hydroxyl group is oxygen hydrogen. That group is replaced by a fluoride ion.
Nate Hegyi: Kind of the same way that you can swap out a shingled roof for a metal roof…the fluoride replaces parts of your enamel and makes it more durable.
Mark Hartzler: fluoride being part of that compound reduces the solubility a little bit, makes it less susceptible to breakdown. It will still eventually break down. You make it acidic enough for long enough. But it it is it is harder to get to that point than than if it didn't have the fluoride there.
MUX: Beignet Interlude out
Nate Hegyi: But those benefits come with an unpleasant side effect. Ingest too much fluoride… especially when you’re a kid… and that added armor will start to turn your teeth a mottled patchwork of white and brown. That’s what that dentist called “Colorado Brown Stain” back in the 1900s. Today, doctors call it “dental fluorosis.”
Mark Hartzler: The area is still pretty hard - not more prone to decay - but aesthetically looks different.
Nate Hegyi: After the discovery of fluorosis back in the early 20th century, the federal government tasked a special group – the Dental Hygiene Unit – to tinker with the levels of fluoride in water. It took them until the late 1930’s, but they eventually found the perfect ratio. One that would keep your teeth strong, but wouldn’t turn them brown. Here’s Rene Najera, the epidemiologist.
Rene Najera: They said that the sweet spot back then was one part per million or 1mg/l of water.
Nate Hegyi: For some places, like Colorado Springs, that’s a lot less than the amount that was naturally in their drinking water. But for most people, it was more. So, few years later, a town in America voted to try boosting their levels of fluoride artificially… by adding a small amount to the public drinking water.
USPHS video: Grand Rapids’ fight against tooth decay started in January 1945 when fluoride was added to the water supply
Rene Najera: and a few years later, about ten, 11 years later, they saw that. Yeah, the the level of cavities had dropped and specifically in children And the oral health had improved and there were no apparent side effects from from the fluoridation of the water at the time.
USPHS video: Now our children can have better health through fluoridated water.
MUX - Mercurial Vision
Nate Hegyi: Other towns – from New York to Texas to Idaho – tried fluoridating their water and had similar results. Cavities in children who were born in the years after fluoridation dropped by more than half. It also leveled the playing field – kids whose parents couldn’t afford to go to a dentist now had stronger teeth… without their families paying a dime. In 1962, the U.S. Public Health Service began recommending that towns add fluoride to their water. It wasn’t mandated. But many towns chose to do so. And today, about 210 million people across the country are drinking and using fluoridated water.
USPHS video: They can drink away tomorrow’s tooth decay!
Nate Hegyi: It was considered a revolutionary scientific breakthrough. The CDC has named it one of the top ten biggest public health achievements of the 20th century – right up there with mass vaccinations. And just like vaccinations… Fluoridation was also controversial. Right from the beginning.
MUX: Murcurial Vision OUT
Nate Hegyi: In the McCarthy era, there were Americans who thought that fluoride in the water was communism in a glass. In the 1950’s, you could find flyers warning of the “unholy three.” The polio vaccine… classroom instructional videos… and fluoridation. All ways for secret communists in the government to control our health and tell us what to do. They warned that fluoride was nothing but a rat poison.
Rene Najera: that it was trying to control your mind, that it was trying to make you sick so that the russians could come over and invade and our young people would not be ready to fight.
Nate Hegyi: This idea was satirized in the movie Dr. Strangelove in 1964.
Dr. Strangelove clip: Do you realize that fluoridation is the mostorously conceived and dangerous communist plot we have ever had to face?
MUX: Soda Baron
Nate Hegyi: It was all part of a bigger worry that some folks had about the role of government in their life. Big public health measures like mass vaccinations and fluoridation, they didn’t start happening in this country until the mid 20th century. It was new and kind of scary. Rene says this is par for the course.
Rene Najera: In public health, there has not been an intervention that has gone without some sort of a controversy from people who don't know the science, they don't understand the science, or they're just plainly afraid of these interventions. And this was no different. You know, you're adding something to the water. Um, we all need water. You know, we all need water to survive. And we like it to be nice and clean as possible. We don't like to have anything in it. And when you're adding something to it, then, yeah, people are going to be skeptical of that and they're going to be worried about that.
Nate Hegyi: Even now, worries about fluoride have survived - outliving the Soviet Union. RFK jr., President Trump’s pick to run the Department of Health and Human Services, called fluoride a poison. He wants to reverse recommendations to municipalities adding the mineral to water. And complicating all this… when it comes to the perceived dangers of fluoride… there is actually a grain of truth - or should I say tooth? That’s after the break. Hey this is O/I, I’m Nate Hegyi here with another medical mystery. I’ll call it the curious case of the Copenhagen cryolite workers.
MUX: Ivory Pillow
Nate Hegyi: Cryolite is a rare mineral used to make aluminum back in the early and mid 20th century. It was mined in Greenland and then some of it was shipped to Copenhagen for processing at a mill there.
Philippe Grandjean: And so they crushed it. And the dust that that created was inhaled by the workers.
Nate Hegyi: This is Philippe Grandjean. He’s a professor of environmental medicine at the University of Southern Denmark. And he says these workers were coming down with very strange ailments.
Philippe Grandjean: if they dropped something on the floor, they couldn't pick it up. And if they wanted to look to the side, they had to move the whole body to the side. It was like, um, the spine was, uh, it was stuck.
Nate Hegyi: Later one of the workers died and there was an autopsy. His joints had calcified.
Philippe Grandjean: the spine actually came out in one piece simply because the calcification had ensured that the vertebrae could not move independently.
MUX: Ivory Pillow OUT
Nate Hegyi: Cryolite is also known as sodium aluminum fluoride. And when scientists tested the urine of these workers, they found really high levels of fluoride.
Philippe Grandjean: the workers were exposed to something like 20mg per work day.
Nate Hegyi: That’s 28 times higher than what the U.S. recommends when fluoridating water supplies. We are talking so high that it causes a condition called skeletal fluorosis. It’s where your bones fuse together, causing arthritis, joint pain, and in severe cases – spinal fusion.
Philippe Grandjean: which is very painful. And it affects, um, the movement of the joints. And so it certainly is something that we want to prevent.
Nate Hegyi: The workers were breathing in the fluoride… but this can also happen when you ingest way too much in other ways.
MUX: The crisper
Nate Hegyi: There was a woman in Michigan, 47 years old, she loved tea - and she loved it STRONG. Every day for almost two decades, she drank a pitcher of tea made from over 100 tea bags. Problem is, teas are often grown in fluoride-rich soil in places like China and east Africa.
Philippe Grandjean: and the tea plant will suck up the fluoride. And when you then pick the leaves and dry them, ferment them. Then the fluoride gets concentrated. And when you pour boiling water on them, you dissolve the fluoride.
Nate Hegyi: Again, this woman was drinking an ungodly amount of tea. And sure enough, she developed skeletal fluorosis.
MUX: The crisper
Nate Hegyi: This condition is very rare in the United States because the government has set limits on how much fluoride can be in our water supplies. The absolute maximum amount of fluoride you’re legally allowed to have in a community drinking supply is 4 parts per million.That’s the standard set by the Environmental Protection Agency and it’s for water that’s already naturally fluoridated – like the water they were drinking back in 1901 in Colorado Springs. Here’s Rene Najera, the epidemiologist, again.
Rene Najera: The EPA does a wonderful job of accessing the toxicity of all sorts of things in our environments and telling us the safe limits.
Nate Hegyi: At that level you might have mottling of the teeth, but no severe spinal fluorosis. If you’re artificially adding fluoride to the water… the U.S. Public Health Service has a much lower recommended limit. 0.7 parts per million. This number takes into account that people might be getting more fluoride from other sources… from swallowing fluoride toothpaste (don’t do that) to drinking black tea with that water. Or that people are drinking more than two liters of water a day – which is considered an average amount. Because the more fluoridated water you drink, the more fluoride you ingest. But with all that in mind, nowadays, 0.7 is considered a good threshold to keep your teeth white and more protected from cavities.
Rene Najera: the dose makes the poison. So if I take a little bit of aspirin for a headache I'm going to be okay. But if I take a lot of aspirin, I'll bleed to death. If I take Tylenol as recommended, I'm going to be fine. If I take way too much, I'm going to hurt my liver. Same thing with fluoride. If you if you have a little bit of fluoride with your water at the level that we have now evidence for, you know, 70 plus years, then you're going to be fine. But if you know, if you have a lot of fluoride and we're talking extreme levels, you know, eight parts per million, ten parts per million, 12 parts per million, then you're going to have an issue.
Nate Hegyi: There’s a long list of acronym institutions that say our fluoridated water is safe. The EPA, the CDC, the ADA (american dental association) the AAP (American Academy of Pediatrics). They all agree. BUT there’s a small yet growing body of research that suggests it isn’t. This is where it gets complicated.
MUX Inspector D
Nate Hegyi: Since the 2000’s, there have been 30 peer-reviewed studies looking into how drinking fluoridated water – both by pregnant women and children – affects the IQs of kids. These were limited studies – a little more than 13,000 people in all, spread across Mexico, China, Canada, Denmark, Taiwan, India and Iran. Philippe Grandjean, the Danish epidemiologist, was a co-author on one of those studies.
Philippe Grandjean: And almost all of them showed a negative association. That is, the more fluoride, the lesser the IQ
Nate Hegyi: The U.S. National Toxicology program reviewed these studies this summer. They concluded – with moderate confidence – that exposure to fluoridated water at higher than 1.5 parts per million consistently correlated with lower IQ in kids. That’s just twice the limit of fluoride the U.S. Public Health Service recommends towns put in the water. But when I poked around on the CDC’s website, I found that there are many communities in the U.S. – like Waterville Valley, New Hampshire or Alpine, Texas – that have naturally fluoridated water that’s actually higher than 1.5 parts per million.
MUX Inspector D
Nate Hegyi: Phillipe’s research has gone a step further than the National Toxicology report. He’s an expert on what happens when fetus’ are exposed to stuff like lead, mercury, and fluoride. A peer-reviewed study he wrote suggests that even if pregnant women are receiving the recommended amount of artificial fluoride in their drinking water… their children are still losing a couple of IQ points.
Philippe Grandjean: two generations of Americans over the last 60 or 70 years have gotten fluoride into their fetal brains. And we have probably lost millions of IQ points.
Nate Hegyi: But while a 2 point IQ drop may sound scary… to put it in perspective… Studies have shown smoking a couple of packs a day can lead to a nearly seven point drop in IQ. Same with being exposed to the chemicals in dryer sheets, hairspray and pesticides. And Philippe recognizes his study may have limitations.
Philippe Grandjean: It's hard to be 100% certain, um, particularly because we we study people who are all different, and there could be some factors that we haven't controlled sufficiently.
Nate Hegyi: Still, from what he’s seen… Philippe tells pregnant women to avoid drinking fluoridated water.
Philippe Grandjean: You can take a shower in the fluoridated water, but I wouldn't prepare soup or gravy from your kitchen supply of water. Or drink it in your coffee or tea. And if you are a tea drinker, make sure that you get something, let’s say, organic tea from Nepal that is low in fluoride or green tea which is also lower than black tea.
Nate Hegyi: This is a hotly debated conclusion and one that has gotten Philippe a lot of flack.
Philippe Grandjean: I've certainly received messages by email from people who are very much in favor of adding fluoride to the drinking water. And so so they think I'm lying or something. And, and and it's very clear that there are differences of opinion. But I'm trying to rely on what I observe.
MUX: Tarte Titan
Nate Hegyi: I need to be very clear here. Philippe’s conclusions put him in the minority. The National Toxicology program says there needs to be way more research to reach the same conclusion. The CDC, the World Health Organization and a host of other medical bodies say that our current fluoridation limits are safe. Rene Najera - the epidemiologist - he pours some cold fluoridated water over this idea that American kids are slightly stupider because of what we drink.
Rene Najera: I've seen those studies. I've looked at the at the data and they're, they're wanting.
Nate Hegyi: He thinks these studies are making some big leaps correlating fluoride and intelligence – Especially considering that IQ tests can be flawed.
Rene Najera: we know that the IQ test is highly unreliable even in adults. It depends on how the questions are framed. It depends on the population that is being given this test, and in children it is even more unreliable. You know, children develop at different rates just naturally. They have different developmental milestones that they meet at different times. And that's why we give ranges to things like walking or learning to read or learning to hop on one leg. We don't say that by a certain age. They have to be have met those milestones. And so what the IQ test and given in some of these kids was doing was trying to do just that, to say at this age, you must have this IQ to be considered normal and then tying it into fluoride.
MUX OUT: Tarte Titan
Nate Hegyi: The American Academy of Pediatrics and the American Dental Association have also come out forcefully against these studies, arguing that they are flawed. But that is the nature of new science. It’s constantly getting reviewed, confirmed, challenged… it is far from settled. Which is why we have traditionally relied on big government agencies like the World Health Organization, the U.S. Public Health Service or the EPA to sift through all this data, take it in stride, and make their recommendations. But the public’s trust in those institutions has eroded. Especially in the wake of the COVID-19 pandemic. We live in a world where unsettled science - or even bad science - can quickly become doctrine.
MUX: Coulis Coulis
Nate Hegyi: This past fall, a federal judge ruled that the EPA needs to take a second look at its maximum legal limits for fluoride in American water. Remember, those limits are 4 parts per million. Philippe Grandjean was an expert witness in that trial… arguing that same point. The judge also said that the U.S. Public Health Service’s much lower limit for artificially fluoridated water poses QUOTE “an unreasonable risk of reduced IQ in children.” And since then, cities in Florida, Washington, Texas and other states have stopped fluoridating their water. That’s the direction that Robert F. Kennedy Jr. wants the entire country to go. On the night of the election, he sat down with Tucker Carlson for an interview and he doubled down on fluoride.
RFK jr: The easiest thing you can do to start restoring American health is just get the fluoride out of the water. You’re going to have higher IQ children, you’re going to have less bone cancer… less…
Tucker Carlson: This is crazy!
Nate Hegyi: I’m not going to touch on all the things that RFK has claimed. A lot of them have been debunked or are based on dubious or unsettled science. But the fact is… if RFK Jr is confirmed, the Department of Health and Human Services will probably reverse their recommendations on fluoridating water. Now, he can’t tell tell towns to NOT put fluoride in their water, but he can reverse official recommendations that say it’s a good idea. This is part of his bigger agenda focusing on personal choice. One that’s pushing back against big public health initiatives. You can still get vaccines… but we won’t mandate them. And if you want fluoride… you can still get it. By taking supplements. Or brushing your teeth with fluoride toothpaste. Or getting that peppermint-flavored topical fluoride treatment at the dentist every six months. It’s your choice.
MUX: Coulis Coulis
Nate Hegyi: This kind of clawback has happened before, by the way. Rene Najera, the epidemiologist, says Windsor Ontario, in Canada, voted away fluoridation.
Rene Najera: And after ten years or so, they saw a dramatic rise in the number of cavities in kids. They came roaring back and they they decided to go back into fluoridating the water.
Nate Hegyi: He says that’s the rub with personal choice driving public policy. Not everyone has access to a choice.
Rene Najera: fluoridation in the water would not be an issue, if we all had universal access to dental care and to brushing our teeth, and we all did it on time, and we all went to the dentist every six months and and brush your teeth at least twice. You know those public health recommendations? If we brush our teeth at least twice with fluoridated toothpaste, it would not be an issue. Unfortunately it's not. We have an equitable system of public health and medicine. And this this is the best thing that we can do to kind of counter that. So you balance the risk of oral health, with the, um, the very unlikely, very unlikely risk of a lowered IQ or developmental delays based on fluoride. Um, especially with the levels of fluoride that we use in our water. And my money is on oral health.
MUX: The Cornice
Nate Hegyi: We would love to hear your thoughts about fluoride. You can send a voice memo to our email - it’s outsidein@nhpr.org. Or leave a message on our voicemail 1-844-GO-OTTER. We have a lot of show notes for this story because it is a tricky one. We’ll have a link to all the studies we mentioned and the pushback they’ve gotten from the American Pediatric Association. We also have a link to a CDC website that tells you how much fluoride is in your town’s drinking water. I’m your host, Nate Hegyi. My mom did drink fluoridated water when she was pregnant, so you can tell me if I lost a couple IQ points in the process. It was edited by Rebecca Lavoie and Taylor Quimby. Taylor is the executive producer of Outside/In… Rebecca is head of on-demand audio at NHPR. Our team also includes Justine Paradis, Felix Poon, Marina Hanke and Kate Dario. Music in this episode from Blue Dot Sessions. Our theme music is by Breakmaster Cylinder. Outside/In is a production of New Hampshire Public Radio.