Fluoride: Is Your Water Safe?

Hi, I'm Wendy Zuckerman and you're listening to Science Versus. Today on the show, we are pitting facts against fluoride. Should we put it in the water? To tell us all about it, senior producer Meryl Horn. Hello. Hi. Okay, there's so much controversy right now around water fluoridation. I know. Which we'll get to. Okay. First, I have to tell you the like wild and surprising story about why we started putting fluoride in the water in the first place. Because it is kind of weird that we do this, right? I guess so. How did it all start? Well, it's actually a detective story. It starts in 1901. So picture a young dentist. Frederick McKay moves to Colorado Springs. He starts seeing patients and immediately notices that there's something weird going on. A lot of his patients have dark brown stains on their teeth. He writes that the color was sometimes dirty or an almost ebony black. Do you want to see pictures? Of course I do. All right. Oh, it's a real black line. A thick line across their teeth. That is unsightly. Yeah. So McKay starts to obsess over this, searching for an explanation. He writes to a friend at one point who responded, quote, I have never seen a stain that penetrated the enamel so deeply before. And this guy guessed that maybe the stains came from dead organisms. They had no idea at first what was going on here. You could say it looks like mold on their teeth. I can understand why they went for the dead organisms. Yeah. It must have been pretty startling, right? Yes. So McKay starts traveling around the US looking at other places, which also have this staining. And he starts suspecting that it's coming from, quote, something in the drinking water. But he doesn't really know for sure. But then he goes to this town in Arkansas, where people only started getting stains in their teeth if they were born after 1909. And apparently that's when the town switched water supplies. So now they just have to see what is in the new water supply. Yes. What's different? And so someone does this analysis and McKay finally gets an answer after three decades of searching. It was the fluoride. Right. This new water in Arkansas had higher fluoride levels. Yeah. Yeah. It had really high fluoride in that water. They weren't adding it, but these places just happen to naturally have a lot of fluoride seeping into the water from the Earth's crust. And now we know that when you drink water with high levels of fluoride, it can mess with the crystal structure of your teeth and that can lead to staining. But then McKay also noticed something else that was weird about these people with the stained teeth. They basically weren't getting cavities. So even though the fluoride was turning teeth brown, it was also protecting them. That's cool. What a Dr. Jekyll Mr. Hyde moment. Yeah. And so they figured, okay, what if we could add fluoride to the water in places that don't already have it? Just a little bit so that we can get this protection from cavities, but not so much that it turns the teeth brown. So this was the beginning. Yeah. And this was the birth story of water fluoridation. So in 1945, Grand Rapids, Michigan was the first city in the U.S. to add fluoride to the water and people were really excited. The government released a PSA about it. The children in Grand Rapids have less tooth decay than they did six years ago. It's working. Yeah. They found that it slashed rates of tooth decay by as much as 70%. Wow. Now our children can have better health through fluoridated water. They can drink away tomorrow's tooth decay. And after that, we started fluoridating water in most of the U.S., Australia, Ireland, and a lot of places in Brazil and Canada. And the CDC lists this as one of our greatest public health achievements of the past century along with vaccines and figuring out that tobacco is bad. Yeah. Wow. That's big. That's biggies. But then fast forward to 2025 and people are not excited about drinking away tomorrow's tooth decay. Well, there's actually been some opposition to this from the start, but recently things are really heating up even at the highest levels. So Robert F. Kennedy Jr., who leads the Department of Health and Human Services, he thinks that fluoride is dangerous. I think fluoride is a poison. But he's not alone. There's a whole kind of chorus of people saying that adding fluoride to the water has been a huge mistake because fluoride is actually really bad for us. Fluoride. It's a neurotoxin and it's found in rat poison. It literally drops IQ in children. It helps cause ADHD. It makes our bones brittle and increases hip fractures. Fluoride in drinking water absolutely increases the risk of thyroid disease. And on top of all the dangers of fluoride, people are also saying now that it doesn't even work to prevent cavities anymore, not that we have better dental care. Not only ineffectual but harmful because of all the science that's emerging. Water fluoridation scientifically proven not to work. Fluoride really the hero that we once thought it was. And so now fluoride is being taken out of the water in some places in Australia and now Utah in the US. So who's right? Is fluoride the hero that we thought it was? Or is it the nemesis that people now say it is? Yeah, that's the question. And just to say that the research on this was not at all what I was expecting it to be. All right. The science of fluoride is coming up just after the break. Welcome back today. We're looking at whether fluoride should be in our water or not. Is it safe or not? Merrill Hahn, PhD, is here with us. Hi, Wendy. Merrill, where do we begin? Is fluoride a poison now? Well, I mean, like a lot of stuff at really high levels, fluoride can kill you. The most dramatic example that I found of this was in the 90s, there was a town in Alaska that accidentally dumped way too much fluoride into the water supply. And dozens of people got really sick. Someone even died. The case study said that, quote, after 24 hours of intractable vomiting, a 41-year-old man was found dead at home. Oh, God. How much fluoride did they dump in the water in that case? It was way more than we normally put in. So like that water that that guy drank had roughly like 350 times more than what we aim for when we fluoridate water. Wow. Ryan. And at really high levels, it can stop your heart. Okay, right. But there's a lot of things that if you have too much of them can kill you, including water that is not fluoridated. The question obviously becomes, are the levels of fluoride that we're putting in the water safe? Yeah, that's the thing that everybody's fighting about with some people saying that it's not safe, some people saying that it is. But there is one downside that kind of everyone agrees is happening, even at these low levels of fluoride that we're putting in the water. And that's the thing that we mentioned at the top of the show where fluoride can stain your teeth. And that can happen even at lower levels too. And at that case, it's not like the photos that I showed you of like these brown teeth. It's just kind of like a whitish stain. But like 10 years ago, we checked to see how many kids in the US have this and it was 70%. And so the government took that seriously enough that they changed the recommendation for how much fluoride should go into the water. It was lowered 10 years ago. Okay. The big thing I hear about now and I've seen headlines saying this and that and the other is around fluoride affecting our brains, some saying it's damaging others saying it's not. What's going on here? Yeah, let's dive into that one since people are really worried about that and it's also where a lot of the research has been. So to walk us through this, I called up epidemiologist Ashley Malin, an assistant professor at the University of Florida. Fluoride. Got it. Yeah. So Ashley, first to remember is when she heard about this idea that fluoride might be bad for us. She was with a family member. I was drinking a bottled water and they said, don't drink that. There's fluoride in it. And I said, yeah, well, it's good for my teeth. And they said, no, fluoride lowers IQ. And I said, there's no way that something would be added to the drinking water that could potentially lower IQ. And what about it felt kind of implausible? Yeah, I was skeptical because this is a widely used public health intervention that's supposed to be protecting our teeth and it's supposed to be something that's good for us. So I just said they wouldn't add that to the drinking water if it was harmful in any way. Like I couldn't even fathom that that was a possibility. Yeah, I hate that. But like she was intrigued enough that Ashley started looking into the research. And at the time there was a little bit there. Like there was a study in the 90s that looked at over 500 rats and found that giving them fluoride could change their behavior. Like it made some of them hyperactive. And then she also found some studies in people like in China, there are a lot of places with these really high levels of fluoride in the water. Naturally. And some of those studies had been finding that people who lived in these areas had lower IQs. So at high doses, yes. But the question is, what about the low doses? Yeah, so that's what Ashley started looking into herself. But there were no studies on lower exposures really at that time. It's like, huh? And so she decided to do her own research on this. She wanted to find out if being exposed to fluoride in the womb could affect brain development. So she got involved in this big study in California. Here's how it works. So they started following a couple hundred pregnant people and they're taking P samples from them. And this way they could look at how much fluoride was in their P. And that kind of roughly maps out to how much fluoride you're taking in. But by the way, this isn't just looking at like fluoride from the water because we actually do get fluoride from a bunch of different sources. Something like 60% of it comes from the water, but we also get it from stuff like black tea. Apparently has a lot of fluoride in it. Pesticides can have it. Or if we swallow little bits of fluoridated toothpaste. So yeah, the researchers here are looking at kind of like overall fluoride exposure. And then they followed up with these moms three years later. So by now their kids are three and they had them fill out a survey about their kids where they asked them about all sorts of stuff. It'll ask symptoms of autism, anxiety, depression, attention deficit, hyperactivity disorder, physical symptoms, so stomach aches, headaches, temper tantrums. Like people will say like, oh my kid has temper tantrums like all the time or like, oh that's really rare, like that kind of a thing. Yeah, so it's rated from zero to two and it'll capture whether the behavior is either typical or kind of over and above what would be considered typical for that developmental stage. Okay. So yeah, they're like casting a wide net here to see if people who had more fluoride in their bodies when they were pregnant went on to have kids with more of any kind of like neural behavioral issue when they were three. Uh-huh. And so what did they find? So Ashley was working from home looking at her data on her laptop when she saw the results. I'm like, oh my gosh, someone, I want someone to check this to make sure this is real. Yeah. Because what did you see? We found that higher levels of fluoride in pregnant women's urine was associated with more neural behavioral problems in their children by age three. Mm-hmm. What kinds of problems? They did have more temper tantrums. They had more anxiety and symptoms linked to autism. Uh-huh. And can you put some numbers around this? I mean, when you say more tantrums, more anxiety, I mean, by how much? Well, it wasn't like, you know, every kid who had some fluoride in the water got anxiety. Right. But what she did is she kind of took the kids who were kind of near the bottom end of getting exposed to fluoride and compared them to the kids who were more towards the higher end of fluoride exposure. And here's what she saw. Their children had nearly double the odds of exhibiting clinically relevant neurobehavioral problems by age three. Whoa. Double the odds. Nearly double. It was almost double. Yeah. Okay. And it's intriguing. I'm not... It's not a huge study. 200 people. Yeah. That's funny. I thought that you would be way more, like, surprised and alarmed at this study. Like, that's how I felt when I saw this. There is like a turning point for me where I was like, what? Like, fluoride might actually be doing something bad here? Yeah. I guess if I'm going to be honest about my biases here, I sort of where Ashley was before she did the study and she was drinking the water and her family member said, this causes brain damage and she's like, absolutely not. And because I know the scientific status quo for so long has said, no, it's safe. So I can see myself looking for holes in this paper. It's not a randomized control trial. So we can't say that the fluoride caused these differences. There might have been other differences between the groups. So what do other studies show here? OK, so I found eight studies altogether that basically did what Ashley did. So they looked at prenatal fluoride exposure. Right, like pregnant women, following pregnant women. Mm-hmm. Yeah. Yeah, and looking at places with like not huge amounts of fluoride in the water, but kind of relatively low levels. The amount you'd find in the city and Australia or the US that fluoridates the water. Yeah. Yeah. And then they followed their kids and looked for behavioral issues or sometimes lower IQ. So OK, so out of those eight studies, right, six of them found bad stuff. And two of them didn't find anything bad. So six out of eight studies did find some sort of like negative effect on the brain from prenatal exposure to fluoride. Yeah. Huh. But the thing is that's all just one group of studies. So other scientists tackle this in a completely different way. And they'll zoom in on water fluoridation specifically and ask if you grew up with fluoridated water, do you have a lower IQ later in life? Right. And a lot of those studies don't find any differences. Oh, that's so confusing. Suggesting what that in Ashley's studies in those prenatal studies, it's not from drinking the water that's the problem, but from swallowing toothpaste. I mean, it could be these other sources. Yeah, it could be like that maybe it's not the fluoride in the water. It could be they're all drinking a lot of black tea or something. Right. It could also be the difference in when the kids are getting exposed because a lot of the studies finding effects, they're looking at kids who are exposed in utero and their fetuses. And a lot of the ones that aren't are looking after they were born. Another thing that we haven't talked about yet here is that we don't really know what the mechanism would be yet. Like there are some ideas, but researchers are only coalescing around one thing that is happening. OK, interesting. I mean, it's because it's such a huge call to say so basically that in all of the places that have added fluoride to the water in the US, Australia, Canada, Ireland, is there any evidence that on a population wide level that those populations are dumber than places that have not fluoridated the water? No. And in general, accused have been going up like in places like the US. Hard to say that now. But and like even one researcher who thinks that there is something here estimated that the difference between like growing up in a community with fluoridated water and not is only the difference of like two and a half IQ points. So that feels like not that big a deal. And so where are you at with this now? Well, I live in New York City and we do have fluoridated water here. But like I haven't stopped drinking it. Like I'm not worried about it for my brain or or my kids' brains. Like I just don't think the evidence is there yet. But I do think that if I were pregnant, like if I had known all this when I was pregnant, then I would have avoided drinking fluoridated water then. Really? I don't know. I've talked to enough researchers on this pregnancy thing specifically that say, you know, they would not do it. They would not drink fluoridated water that it freaks me out now. Yeah. So then what are you supposed to do if you're pregnant? Get a new water supply? I mean, it's really hard, right? Because in theory, like you could try bottled water, but we don't actually know a lot of the time how much fluoride is in bottled water. Some of it might have fluoride in it too. Yeah. And then you got to worry about the bloody microplastics with the hormone disruptors. So we talked about last season. I know. Like I think it's not perfect, but like I would would probably look into a filter. There's some filters that get fluoride out of the water or honestly, if it was just for a limited period of time, like if I were pregnant, maybe I would just buy distilled water that didn't have any fluoride in it and like try to drink that. But like this is all probably being super cautious since tons of kids are exposed to fluoride in the uterus and don't have these behavioral issues. And there are just still some big unknowns. OK. So where we're at with the brain stuff and fluoride is that there is some emerging evidence that if you're pregnant, this could be doing something to the fetus. The science is still unclear, but based on where it's at, you think it's worth thinking about. Yeah. For us big kids, come out of the vagina, make in podcasts, is there other stuff that we need to worry about? Well, it's not just about the brain here. Like some people are worrying that fluoride might be making our bones weaker or increasing our risk of thyroid disease, like hypothyroidism. Yeah. And there is some evidence that that stuff is real, too, even at relatively low levels. Really? Yeah. Yeah. So like for the thyroid, like we know that the thyroid needs iodine, right? If you don't get enough iodine, then you can get a goiter. Yes. So fluoride can sort of outcompete iodine. So in the past, we've actually given fluoride as a treatment for people who have overactive thyroids. And there was a study that found that people who lived in an area with fluoridated water were twice as likely to have hypothyroidism than people who didn't. But like other studies haven't found those associations or like one found that it was only significant if you also had an iodine deficiency to begin with. So what do we make of that as well? What do you make of it? Yeah. I mean, it's not like I looked at the evidence and was like, oh, this is real for sure. Like fluoride is giving us all hypothyroidism. And then for other stuff, it's even less convincing. Like for bone health, there were some studies that say that drinking fluoridated water can increase your risk for bone factors. But there was a meta-analysis that looked at everything together and said that there was no increased risk. Uh-huh. Reassuring. But then like, I don't know, for me, even if there are just a few studies saying that some of these risks could be real, it doesn't make me feel great because like, I mean, the stakes are so high. We're doing this at such a big scale that ideally you'd want to see like a mountain of rock solid evidence of studies all saying this is totally safe. Like this is okay to be basically forcing this many people to be having this chemical. Right. And we don't have that. I talked to Ashley about why we don't have a more definitive consensus on this. I mean, why has it taken so long? Is this kind of a failure of science? I think a big part of it is that it wasn't acceptable to ask these questions up until recently. Do you even ask the question you'd be considered a tinfoil hat wearing conspiracy theorist probably up until 10 years ago? Wow. Yeah. That recent. Yeah. All right. Well, this this episode has taken quite the turn. Yeah. I mean, clearly fluoride is not the devil or poison as some people are claiming at the, you know, levels we put in our water. But it really is frustrating that we don't have more science on this and the science that we have is muddy. I guess that's why you see these big fights online with people, some saying it's safe, some saying it's not because you really can cherry pick the data on all these fronts. You can pick your it's bad for the thyroid study and you can pick it's you're bad for the brain study or you can pick a study that's saying the opposite. I guess this. But what it does tell us, though, the fact that for a for a lot of this stuff, it is muddy and that you do see studies showing both sides tells us that whatever fluoride is doing in the water, it's not super dramatic because then you would see the same results in, you know, basically all studies. Yeah, that seems true. OK, so we've talked a lot about the potential risks. Now we need to talk about the potential benefits. The reason that we have been doing this for the first place is to protect our teeth. So is fluoride still doing that? That's after the break. Welcome back. Today we're talking about fluoride, Merrill. Any benefits to putting it in the water? Well, scientists all agree that back in the 1940s, when we first started doing this, there is this huge benefit. But lots of people today are saying that things are different now. And like I think it does kind of make sense because when we first started doing this, our team was very much in the process of doing this. And it makes sense because when we first started doing this, our teeth were way worse. Like we didn't go to the dentist as often. We didn't get sealants or brush our teeth with fluoridated toothpaste. Right. So something like putting fluoride in the water had this big potential to make a huge difference because our teeth were so crappy. Right. Were now people say that like, well, we don't really need to be doing that anymore because we have all these other like, you know, tools in the toolbox to help our teeth. So are they right? Or are they just adding fluoride to the water? Is it still preventing cavities or not? Well, now we actually have like kind of a perfect opportunity to look at this because as cities are taking fluoride out of the water today, we can see like, okay, how much like do the teeth actually get worse in places that do that. Right. And so that's what I wanted to talk about with Lindsay McLaren. She's a professor in community health sciences at the University of Calgary in and this all first got on her radar back in 2011 when her city decided to stop putting fluoride in the water. When it when that all came out, I just it was just fascinating to me. Like, oh, we're not going to have fluoride in the water anymore. Isn't isn't that interesting? And Lindsay and some of her public health like nerd friends saw this and they published a notp ed in the local paper, just kind of questioning whether this was actually a good idea. And like the hate mail came instantly. Like we got hate mail immediately. Saying what? Yeah. Oh, just like, you know, you guys are liars and, you know, you're you're fraudulent. And I was like, oh, OK, this is very interesting. You're like, let's dive deeper into this field where I'm getting hate mail. Exactly. Exactly. Because I actually and I feel like this is something where I was kind of misunderstood, like I was actually genuinely open to some of the comments I was receiving. So Lindsay was like, yeah, let's do some science here. Like we're taking fluoride out of the water. Will our teeth get crappier? Yeah. And I wanted to talk to her about this one study that she did looking at cavities in kids. They did this one about seven years after the city stopped water fluoridation. And so they looked at kids who had basically gone their entire lives without fluoride in the water. So these kids were about seven years old. And they they started by sending out teams of dental hygienists and researchers to schools in Calgary to check their teeth. So they were just all over the city, you know, for an entire year. They were like set up shop in the nurses office, usually, where a dental hygienists would look at each kid's mouth one by one for a science of tooth decay. And Lindsay's team wanted to make sure that the kids felt comfortable with this. In fact, the kids seemed to find it kind of fun. And like we'd have sort of groups of five kids come in at a time and be on deck. And like they'd be dancing around and like they thought it was fun because they got pulled out of class. And because of the dental light, we had sunglasses for them and they love the sunglasses. Like they were just walking around like they were so cool. It's like a dance party. Yeah, yeah, it was it was really cute. And they weren't just looking at these kids in Calgary that had lost fluoride from their water. They were also doing this entire thing in another city that was nearby called Edmonton that kept fluoridating their water. So what did they find? You're stringing me along like floss here. OK, OK, so yeah, we've got five thousand second graders across these two cities. And now they can finally see did the kids who grow up with fluoride added to the water have fewer cavities compared to the kids in Calgary? Yes. So what did they say? So the prevalence of of dental caries in Calgary kids in their baby teeth was about 65 percent. Fluoride no longer in the water. 65 percent had cavities. All right, drum roll. What is it when fluoride is in the water? That was compared to about 55 percent in Edmonton. It's like 10 percentage points different. Yeah, yeah. So that's a percent of kids that have any any cavities at all. Well, what did you think when you saw that data? This was larger than I expected. OK, and what about other studies? So other studies generally find the same thing. Kids do tend to get more cavities when they grow up without fluoridated water. OK, OK, so one thing that we've been told about fluoride still true. Still good for our teeth. Yeah, these kids are getting fewer cavities. And I know maybe you're thinking who cares? The little cavity here or there maybe doesn't matter so much. Right, it's just their baby teeth. They're going to get more. Well, it actually does matter. So like if you lose your baby teeth early, like if you have to get them extracted, then your adult teeth might not come in as straight. So that could affect you for the rest of your life. And we do have evidence that living in a place with less fluoride in the water will make it more likely that kids will need to get teeth extracted and also get intense dental work done, like where they'll need to go under general anesthesia, which ideally like we'd want to avoid putting kids through that. Yeah. And we also have evidence that fluoride is particularly good for kids who come from poorer families, like in Lindsay's study, after Calgary stopped fluoridating their water, it widened the gap between the richer and the poorer kids when it came to like how bad their teeth were. Not all studies find this to be true, but Lindsay's does seem to be like one of the best ones. And so what about adults? Does it matter for the for us? Well, it's like it's kind of hard to tell how much it matters. Like if you're already an adult and you live in a place with fluoridated water, how much that makes a difference? Like one study said that there was just two percent less tooth decay for adults who lives in places with more fluoride in the water. Oh, it's tiny. Is that because we're better at brushing out teeth than kids? Partly, yeah, actually. And also apparently I just learned this that the enamel of baby teeth is thinner and more porous. And then even after you start getting your adult teeth, those teeth are also more cavity prone since they're softer. It takes them years for them to reach maximal hardness, according to one paper. Wow. Maximal hardness. Yeah. That's an odd way to just describe anything to do with children. So yeah, it's like pretty convincing to me that fluoride in the water is still helping our teeth, which brings us back to Lindsey's study. So there's one more thing I wanted to tell you about that, which is about how people reacted to it in Calgary. So after her studies came out, the town actually ended up voting on this and decided to put fluoride back in the water. Whoa. They listened to the teeth science. They cared about their teeth. Yeah, it seems like it. Like they had a vote and 62 percent of the people said, yes, we want to fluoridate our water again. And this was by far the largest majority in our history. It was in the past, it's been more like, you know, 49, 51 type of type of thing. Wow. Yeah. So this was quite a strong sign of support. Yeah. So her study got a lot of attention, like even in the US, here's some of that coverage. In Calgary, there was life before fluoride was removed from drinking water and life after. Children, mostly children, had to suffer so badly. So yeah, I asked Lindsey like where she lands after all this. Should we be putting fluoride in the water? Yes, that recommended optimal concentrations and keep the research going. So don't cut research funding. That seems like a pertinent thing to say right now. Sure does. Sure does. All right. Well, but Lindsey's looking at the teeth. Was she also thinking about all of the other potential risks around brain development and thyroid stuff when she answered that question? Yeah, we talked about that research. Like it's something she's keeping an eye on. But so far it hasn't changed her mind on water fluoridation in general. Hmm. Oh, messy. I mean, zooming out here, you did speak to a lot of scientists in this space. What are they telling you when when they put the risks and the benefits together here? Where do they stand? I mean, they were really split, actually. I was surprised by how many scientists, including some dentists who told me they think we should either stop or they were like seriously doubting it. Like there is one that I talked to who used to be a big fluoride supporter. And he'd been thinking more and more about this research. And I asked him like, all right, like if you're in charge of the machine, do you cut it off? Yeah. And he just like paused for 20 seconds in silence. Well, he like tried to figure out what to say. And then he just said like, sorry, I can't give you an answer. We need more research, which is kind of where I'm at. Like I just I keep. I was just so barrel. Do you think we should keep fluoride in the water? I don't know. I am right there with him because like I can really see it from both sides. I think what's so hard for me is that I'm pretty convinced that the benefit to the teeth is real. But it's like at the end of the day, it's still just the teeth where like even if the science on the brain damage isn't as convincing, the stakes are so much higher that if the effect is real, we need to stop fluoridation, even if it is good for the teeth, obviously, we can't be giving people something that might be damaging their brains. Right, right. What do you think? That science fest. 20 seconds in silence. Is that about it? OK, so, Merle, how many citations are in this episode? We had a lot. 105 citations. Whoa, 105. Wow. So before you send us angry emails, Instagram messages, please have a look at our transcript. How could people find these 105 citations? Yeah, you can go to the show notes and then follow the links to the transcripts. But you can also send the angry emails if you want, you know, we don't mind. It's true. On Instagram, we are science underscore VS. My TikTok is at Wendy Zuckerman. Come say hello. Let us know what you thought of the episode. All right, thanks, Merle. Thanks, Wendy. This episode was produced by Merle Horn. With help from me, Wendy Zuckerman, Rose Rimler, Michelle Dang and the Keddie Foster Keys. We're edited by Blythe Turrell. Mix and sound design by Bobby Lord. Fact-checking by Erica Aikiko Howard. Music written by Boomi Hideka, Peter Leonard, Emma Munger, So Wiley and Bobby Lord. Thanks to all of the researchers that we spoke to for this episode, including Professor Christine Till, Professor Jonathan Broadbent, Dr. John Morris, Professor Bruce Lanfier, Professor Lok Do, Dr. Maria Kippa, Professor Philip Hujul, Professor Steven Peckham, Dr. Tomasso Filipini and Professor Steven Levy. Besides VS. is a Spotify studio's original. Listen to us for free on Spotify or wherever you get your podcasts. And if you are listening on Spotify, follow us and tap the bell icon so that you get notifications when new episodes come out. I'm Wendy Zuckerman. Back to you next time.