Body Stuff with Dr. Jen Gunter

I'm doctor Jen Gunter. I love science and I hate when people twist it. Your immune system needs a big scorbal supplement's milk a week, and there's a lot of twisted medical misinformation out there. Are toxins literally purify you. Yeah, that's ridiculous. Chugging a gallon of water means you'll eat fewer calories. Oh, it's so painful. We're exposed to medical myths, whether we're looking for them or not. There are news stories Instagram and Facebook, post Flying Past twenty four seven,

TikTok Twitter. Who has balid information and who's just trying to sell you something? How do you sort the medicine from the mayhem I'm doctor Jen Gunter, and I'm here to help. From the Ted Audio Collective, this is body stuff. I'm a doctor, a practicing gynecologist, and I've made up my mission to give women the facts that they need

to understand their bodies. In my twenty five years of talking with pay, I've learned that medical misinformation is a problem for everyone, and every single one of us is susceptible. So this show is about debunking some of the stickiest myths out there while helping you understand how your body really works today. Why you don't need eight glasses of

water every day, you need a water day. We're going back in time to find the origins of that myth, and then we're going to meet a kidney expert who's going to illuminate just how hard our bodies work for us to maintain our hydration. It works like an exquisitely designed atomic balance machine, right, you need to keep everything in balance. But first I want to tell you about something that happened to me when I was ten years old.

It was a time in my life when I got asked a lot about my urine and it ended up setting me on a path to become a doctor. It was the first good weekend of spring nineteen seventy seven in Winnipeg, Manitoba, the kind where the sun feels hot and you're just raring to get outside. I was messing around with my brother's skateboard, going down the street, and then all of a sudden, I was flat on my back on the concrete and I was in a terrible amount of pain. It felt like my insides were on fire.

The next day, I'm sure I didn't look well, so we went to the pediatrician, who took one look at me and called a general surgeon, who took one look at me and sent us to the emergency department. They gave me something called an angiogram, and I remember the doctor pointing to the X ray screen explaining what he was seeing, and of course it just looked like a snowstorm to me. But that's when I learned that when

I fell off my skateboard, i'd ruptured my spleen. The good news was I wasn't going to need surgery, but there was something else. It looked like I had hydro nephrosis, meaning my kidney was full of fluid, and I needed to see a pediatric urologist. He sat us down in his consultation room and started to explain to my mom what needed to happen. And I could tell she was very confused. I think the doctor could tell as well, and so he gestured to me and said, hey, you

come over here. This is your body. You should know how it works. So I came over and I sat down. I traded places with my mom, and he drew a little diagram and he explained how the kidney worked and what he thought was wrong, and the test that I was going to have to have, and the surgery that I was probably going to have to have as well. And that doctor took the time to explain my body to me. It really helped me not feel scared or overwhelmed. And that experience made me decide I wanted to be

a doctor. I loved the science and I wanted to be able to give to my patients what that doctor gave me that day, that empowerment of knowing how your body works and how to use that knowledge to help improve your health. Eventually, I did have surgery to remove my left kidney. I've lived most of my life with just one kidney, the organ that's largely responsible for regulating our body's hydration. But you want to know something, None of my doctors ever told me to worry about how

much water I was drinking. I graduated from medical school when I was twenty three, so I've been a doctor more than half my life, and I've seen firsthand the problems that happen when people get misconceptions about their health. And a lot of these misconceptions they start with the Internet. I'm not one of those doctors who rolls her eyes when her patient comes in with reams of advice from doctor Google. That tells me that my patient is engaged,

she wants to learn. But there are a lot of bogus recommendations out there, and often they're being pushed by brands and influencers. A lot of them sound like they're making sense in a sort of science ish way, like the eight glasses of water a day thing. Hey, we're made of water, so why wouldn't we need lots of water? But that's not science. So what's behind this myth? How did we get to eight glasses of water a day? Anyway?

There are a couple of potential origin stories. One is a paper from nineteen forty five that suggests the body uses about eighty four ounces of water a day. And there's another paper from nineteen seventy four from a pair of nutritionists who recommended an equivalent of six to eight glasses of water a day for the body to function appropriately. But these papers became distorted over time like a bad

game of telephone. These experts were recommending that we drink six to eight glasses of water a day on top of everything else. They were saying, this is the amount of water the body needs to function, But that water doesn't have to be water you drink from a glass out of your tap. Water is in everything. Think about a breastfed baby. All they're drinking is milk. The body is able to remove the water from the milk, so

the baby never gets dehydrated. In the same way, once we start eating slid food, our bodies continue to extract water from everything we consume. Everything we eat or drink counts, So the water in your apple counts, the water that's in the bread that you eat counts, even coffee counts. Any fluid counts. Look, I get this as a real record scratch freeze frame moment for a lot of people. But we don't just get the water we need from

plain water. And if you have one of those days where you just drink coffee all morning and you don't feel great, maybe you're a little headachy or a little jittery, it's not because you're dehydrated. Maybe you had a little too much coffee or you had it on an empty stomach. If you like drinking six glasses eight glasses of water day and your doctor hasn't advised against it, that's probably fine. What I'm saying is that there's nothing medical about this number.

We get to make choice races about what we put into our body, and this is one of those choices. If you think about it, just using common sense and putting the medicine aside, does it seem realistic that we evolve needing to consume that much clean water every day In the span of human history, access to clean, plentiful drinking water is a relatively recent phenomenon, and even today, in many parts of the world, accessing clean drinking water sadly isn't as easy as walking into your kitchen and

filling up a glass. It seems unlikely that our ancestors carry giant water bottles around with them at all times. And yet the mythspread and spread and spread. But why is this myth so sticky? It turns out there's a mix of factors, including a little bit of intrigue and one particular culprit that deserves a lot of the blame, the beverage industry. Sometimes water just isn't time unquenched. Thirst

has become a chronic problem America. If you are going to sell something, you've got to have a reason to sell it. You've got to create a market for it. Things like pre hydrate. I mean, what's that mean? Drink ahead of your first train. You've got to tolerate more fluid. Your brain doesn't know when you are thirsty. Doctor deb Cohen went to medical school in the UK, but instead of becoming a clinician a doctor who sees patients, she

became a journalist. Back in twenty twelve, during the lead up to the London Olympics, she was the investigative editor at the British Medical Journal. She wrote a report called The Truth about Sports Strengths and It's set off a bar arm in the beverage industry. The report looked at the history of sports drinks like Gatorade and how they're advertising.

Basically invented the modern fear of dehydration. It was really in the kind of the boom of the marathon era in the nineteen seventies that sports drinks really took off. It started life in Florida at the University of Florida and Robert Cade was the renal physician and he developed this drink for the Gators football team. It was effectively water, sugar, dasher sodium, and a bit of lemon juice, so quite simple,

and it was supposed to help alleviate cramps. And then it was brought up by Quaker Oats and they spotted a big market, and that's really where the science of dehydration started. Okay, so we're not talking about clinical dehydration, which is a real condition. For example, the time I had food poisoning and I was up all night vomiting, so I had to go to the emergency department and get an intravenous But this is healthy people, So this is a whole different phenomenon. And so what they turned

into an illness was exercise induced dehydration. Exercise induced dehydration, now that sounds a lot more important than you're a bit First, you if you've been running and sweating. If you tell people that it's all about the science, then people are more likely to believe it. Beverage companies, especially Gatorade, commissioned studies looking for results that would bolster their sales pitches. By the time doctor Cohens started looking into these studies,

there were a lot of them. Glaxo smith Kline at the time, the company behind a popular British sports drink called lucas Aid, claimed they had more than a hundred clinical trials. That's a lot of studies, and the studies were a little bit off. Some of the studies we're actually having a bit of a laugh about. So what you would do is you would starve people overnight, you'd fast them overnight, and then you'd ask them to cycle to exhaustion. One group you would give a sports drink

containing sugar, and the other group you would give water. Well, guess what, the people have had a bit of sugar are going to well perform the people that have been starved and had water. It's not rocket science. And so they are all sorts of these all sorts of these kinds of studies that they do, and you look at it and go that just does not happen, and it doesn't matter that it's not clinically relevant. Now you've got something that looks statistically different, and you can peg a

marketing campaign around that exactly. And if you throw enough darts at a dark boat, if you've got your eyes blindfolded, then one of them is going to hit the dark boat. At some point. The studies were junk, but the science fish conclusions they made began to spread, especially the idea that we couldn't rely on our own bodies to tell

us while we were thirsty. One of Gatorade scientists even said in two thousand and eight, and I quote, the human thirst mechanism is an inaccurate short term indicator of fluid needs. Unfortunately, there is no clear physiological signal that

dehydration is occurring. I think even the Mayo Clinic had information that was based on science that have been ultimately derived from the sports strengths industry about when you should hydrate and how you should hydrate, and it filtered down to influence school guidance in the UK where kids playing soccer would have to go and stop every fifteen minutes twenty minutes to rehydrates. And you speak to the teachers and be like, yeah, it's just kids like running around.

They just need to peel all the time, So kids running off constantly. Even the US military was in on the quasi science. In the early eighties, the Pentagon was citing Gatorade Sports Science Institute studies claiming their drinking sports drinks could prevent heat stroke, a huge concern for soldiers fighting desert wars. But those studies were bunk. There was no evidence that drinking fluids reduced the risk of heat stroke. Even today, the US military remains Gatorade's the biggest customer,

your taxpayer dollars at work. I was warned off several times as well from doing the story. Are you sure you know what you're doing? And a spot some people in the US quite a bit of sources, and they tried to have studies published that were negative and they just could not get them published. And they'd been warned off doing their research as well, and they were saying to me, do you realize how what you're doing here? And I literally probably naively just thought, well, sugary water, guys,

I mean, how big a deal is this? But as doctor Cohen started her investigation, she began to see. There was a lot of money intertwined with the junk science. Sports drink companies spent huge sums sponsoring youth sports, funding sports medicine doctors, and putting their logos on the world's most beloved teams, and it was like a holy grail. You go to sports conferences, to sports medicinal sports science conferences. It's displayed everywhere you know sponsored and you don't criticize

the sports drink. So sports strinths have somewhat fallen out of favor since their heyday in the nineteen eighties and nineties. But another product has taken its place, and now it's the number one selling beverage in the world, bottled water, and big Bottled Water is very happy to have you believe that you can't trust your thirst and that you need a minimum of eight glasses of water a day. After the break, we're going to talk about why this

myth just won't die. We're back before the break. We learned the origin of the eight glasses of water a day myth. We believe myths like this for a lot of reasons, but a big one is something psychologists call the illusory truth effect. When a piece of information is widespread, and you hear it over and over again, you're more likely to believe that it's true. There are a lot of examples, statements like we only use ten percent of our brains, or eating carrots will help you see in

the dark. None of these things are true, but I bet you've heard them repeated over and over again. Politicians and marketers take advantage of this all the time, and it works because when you're assessing whether something you've heard is true, you typically rely on two things. Whether the information makes common sense and whether it feels familiar. The research has shown that familiarity can even be more convincing than rationality. Rationality is hard, but remembering if you've heard

something before, that's easy. And here's the thing about the illusory truth effect. No one is immune, not even doctors. There's a one day a year in March we call World Kidney Day, dedicated to improving awareness of kidney disease, and a few years ago the theme of World Kidney Today was drink a glass of water to help your kidneys, which is just crazy, right, It doesn't make any sense. It's not grounded in science, but you know it is grounded in funding for World kidney day, which I believe

comes from dan in a manufacture of bottled water. It's like the deep state of hydration. That's doctor Joel Toff. He's a kidney doctor, otherwise known as an nephrologist. I called up doctor Toff because what do we do in medicine When we don't know the answer, We look for an expert, we call a consult and doctor Toff is just the chemistry wizard for the job. I'm a lifelong nerd who has been fascinated by the chemistry of body

fluids going on three decades. I love nerds. There are an infinite number of fascinating aspects of body physiology or disease states. And one of the truths about medicine is that once you start learning about any one of these conditions, they become more interesting. And back in nineteen ninety five, when I was a senior in medical school, I became real interested in fluids and electrolytes. So the precious bodily fluids, the precious bodily fluids. That's right, that's my favorite movie.

That's a doctor Strange love. Doctor Toff knows that the most important thing about precious bodily fluids is that they stay in balance, which brings us to the tragic case of Jennifer Strange. So I want you to kind of rewind back to two thousand and seven, and the hottest thing in two thousand and seven was the Nintendo Wii, and this radio station got their hands on one and they were running a radio contest. The contest was don't

we for a Wei? The radio station invited eighteen contestants down to their studio to see who could drink the most water without having to pee, and there was one person who entered. Her name was Jennifer Strange, twenty eight year old mother of three, and she ended up drinking two gallons of water in an hour. That's a lot of water, so much water that a nurse actually called into the station to warn them this was dangerous. You can overload your system with too much water. It can

be really unsafe. As Jennifer left the radio station and she was already complaining of a headache, and what she actually had was a condition called cerebral edema, which happens when you wash your body out from all the critical salts, and when you do this, water will shift from your bloodstream into your brain. Cause increased swelling of your brain that cause headaches, nausea, seizures, coma, and death. And she

ended up dying on her own bathroom floor. A couple of hours later, Jennifer died from a condition called hyponatremia, meaning a dangerously low level of sodium in her blood. She threw off her body's delicate balance, something we've evolved to rely on. It's called homeostasis. The body maintains a stable internal environment to provide optimal health for the cells

of the body. Right, you can imagine for these cells to grow and to be healthy, they need regulated amounts of sodium, potass seem even things like body temperature needs to be regulated. All these things need to be in an optimal range for growth and health, and that process of maintaining everything in that type band is called homeostasis.

We've evolved to maintain homeostasis through finely tuned mechanisms. The sense when things are awry, when we've gone a little bit too far in one direction or a little bit too far in the other, and makes adjustments to return us to our state of balance. Think about the mechanisms that maintain us in homeostasis, like autopilots. I think that's perfect, right, So you can think about body temperature is a classic one, right.

So if we get too hot, we start to sweat, water evaporates from our skin that lowers our body temperature back down. We get too cold, we shiver and all that generates heat and brings us back to a normal body temperature. So we have processes that control us from getting too hot and from getting us too cold. Body temperature is just one example of the autopilots that are body has to maintain homeostasis, and our kidneys well, they're

the quarterback of homeostasis. They help to maintain the balance of almost every electrolyte in our body. They help with blood pressure, they're crucial for maintaining pH and they maintain our level of hydration. One of these autopilots is called osmolality, and osmolality is just a measure of the total amount of compounds in solution. And so an analogous is just how salty the soup is. As the osmolality goes up, soup gets more salty. As the osmolality goes down, soup

gets more dilute. In this case, the soup is our blood to be a little bit more precise. The fluid part of our blood our plasma, and the kidney regulates our osmolality so it stays in a healthy range. Jennifer's Strange died because she drank so much water that she pushed her osmolality far below the healthy range, and her kidneys just couldn't keep up. Today, hypenatremia is most often

seen in athletes who are overhydrating while exercising. Doctors first started seeing it in ultra marathon runners and iron man triathletes in the nineteen eighties, a period of time that nicely coincides with the messaging coming out of the Gatorade Sports Science Institute. And it's not just extreme athletes. Doctors have seen hypenetremia in high school football players, students in yoga classes, and more. Thankfully, hypenetremia is relatively rare because

of our body's amazing ability to defend homeostasis. I just want to run this morning, I went for three mile run, and I'm the thirsty and a bit hungary. So how's my one kidney because I only have one keeping me working right. So you came back from your run, and presumably during that run, you sweat, you lost a little bit of fluid that way, and that loss of fluid is going to make your body salt here, it's gonna

make the soups alter. Your osmality goes up. This is you're pushing your body out of that homeostatic range and it needs to return that osmolality back down. And the way that it does that is two factors. One increased thirst. And so increased thirst is a sensation that your body gets that'll change your behavior. It'll make you go to the sink, pour yourself a glass of water and drink it. So in addition to thirst, your kidney is going to

respond to that increase in osmolality. And the way that it does that is it's going to change the type of urine that you make. You're always making urine, you're always getting rid of You're constantly getting rid of waste products. But one of the variables is how much water is excreted along with those waste products. In other words, if you're drinking a lot of water, you're going to pay more, but that doesn't mean you're getting rid of more waste.

You're getting rid of the same amount of waste. It's just diluted in more water. Yeah. My tagline on Twitter says, thinking the kidney's product is urine, it's like thinking a factories product is pollution. Urine is the byproduct. What the kidney produces is homeostasis. So how much water should we drink? We should drink enough water so that you're not thirsty. I tell my patients, you know, anytime that you're thirsty, go ahead and drink a glass of water, and maybe

have one glass of water on top of that. It's not going to harm you. But I don't advise my patients to count their glasses of water unless unless they have kidney stones in their past, or if they have autosomal dominant polycistic kidney disease. If you have an intact thirst mechanism and you have access to water, are you going to get dehydrated? No, let's put it this way. People with increased sodium will drink from a toilet. The derived to drinking is so strong you will not get dehydrated.

If there's a glass within a mile of you, you'll get that water. Then you'll be fine. See. Now you can be liberated from any anxieties you've ever had about whether you're drinking and off water. You're welcome. Then doctor Tooff told me something really cool about how our bodies know when we've dranken of water. Yeah. So there are what we call osmoreceptors. They're located in a center part of the brink called the hypothalamus, and they're going to

constantly measure the osmolality of the body. And they're actually the butt is very sophisticated. It knows when you're drinking, and it'll start to suppress the hormone that drives thirst as soon as you start to drink, right. It doesn't even wait for that fluid to lower the osmolality in the body. It's absolutely aware of what happens when you drink, and it says, hey, we're gonna slow this cycle down.

We know that you're already compensating for what we're seeing, so it'll suppress those hormones that are driving that thirst once you start to drink. Yeah, I thought that was fascinating. You know that it takes about ten minutes for the water that you drink, you know, to get into your bloodstream, and that your brain, you know, knows, you know, within a minute or so that you've consumed enough and it's already like making the calculations based on you know what

it's sensing in your mouth and your esophagus. I mean, it's such a fascinating autopilot, right. It's just way more advanced than we had thought. The body is amazing, isn't it? Okay, I have a few more little things I want to clear up now that I have my own kidney consultant. So let's play a little game kidney fact or fiction. Staying hydrated makes your skin glue factor fiction fiction. No evidence that it improves the glow of skin. That said, if you really get dehydrated, skin's not going to be

in good shape. Drinking eight glasses of water makes your brain work better? Yes, or now? So, there is some data that this was done in school children that increasing hydration right before some tests improved some aspects of cognition. There are two studies that I could find on this. Neither of them were very large, neither of them are very convincing. But I also didn't find the big test

that said this is absolutely fiction. I would guess fiction, but I would leave a possibility that there's some truth to that. Caffeine is a diuretic factor fiction fiction This has been studied pretty rigorously. There is no evidence at all that caffeine dehydrates. You can include that cup of war when you count your cups of water if this is something that you'd like to do, and coffee is no different. So there you go. Friends, if you'd rather have a cup of coffee than a glass of water,

you do you. Before I can let doctor Talf go, I had just one more question, so I got to ask, did you check the color of your urine? Oh? Absolutely, I'm like every other person. No, I'm always interested in it. I'm always interested in it because it gives me a you know, it's a window into what's happening in my kidney, right, and I'm naturally intrigued by that. But I don't think it changes my behavior. If I'm thirsty, I drink. You let your body run the outer pilot. Yeah, here's one

of the big secrets of medicine. It's not as hard as you might think, and it certainly doesn't all belong in ivory town hours or dressed up in lab coats. I had an AHA moment when I was twenty or twenty one years old, sitting in medical school, and the professor started talking about hydronephrosis, the exact same diagnosis that I had when I was a kid, and he explained it using the same language as my pediatric urologist. I

sat there thinking, Wow, that knowledge is held up. What I heard when I was ten is not any different than what I'm hearing now ten years later in medical school. My knowledge is held up over all this time, And how empowering was it for me to actually understand how my body worked when I was going through all those scary things. A lot of medicine is very complex, and if you're going to be a doctor, you need to know all the background and the nitty gritty details matter

a lot. But if you're just worried about taking care of your own health or your families, there's a lot in your power to understand. One of my favorite things about being a doctor is when I explain something to a patient about how their body works and they have that moment of realization. All the puzzle pieces fall into place and they say, Wow, I didn't know how that worked, and now I do. I hope you'll stick around for

the rest of the season of body stuff. We'll be breaking down how your body works while busting one medical myth at a time. Next week, we're diving right in with your digestive system. Why just poop smell bad? Because of it? Things inside? Not many of us are comfortable talking about our poop, but I'm not many of us. We're going to talk about why today we're so freaked out by feces and we're going to find out what our poop can tell us about our health. Body Stuff

is a member of the Ted Audio collective. It's hosted by me doctor Jen Gunter and brought to you by TED and Transmitter Media. This episode was produced by Lacy Roberts and edited by Sarah Knicks. The rest of the team includes Camille Peterson, Alice Wilder, Gretta Khane, Michelle, quint Ban Ban Chang, and Roxanne high Lash. Alex Overington is our sound designer and mix engineer. Paul Durban and Nierja Robindon fact checked this episode. Special thanks to my one

kidney for keeping me going. We're back next week with more Body Stuff. Make sure you follow Body Stuff in your favorite podcast app so you get every episode delivered straight to your device, and leave us a review. We love hearing from our listeners. See you next week. An un