Hi, I'm Wendy Zuckerman and you're listening to Science Vs. Today we're putting facts against Fiber. That's right, the world's least sexy nutrient has been getting a glow up recently. You might think of Fiber as something your grandpa kept going on about, but all over TikTok and socials, the sexiest people online are obsessed with it. Fiber! That's the answer! Fuel your body with Fiber! I need to eat more fiber in so do you. It'll change the way that you think of food forever.
People say that this one little nutrient packs a huge punch. It'll supercharge your gut. Say goodbye to gut inflammation and hello to the best poo's in town. Start eating food that is rich in fiber and be dropping logs daily. People are saying it can help you lose a ton of weight. Fiber? It's literally going to shrink your waistline. I've lost weight, my belly fat's gone, my man boobs are gone. Apparently, within a Fiber, your depression could be gone too.
So you're not eating enough fiber? Your anxiety is going to stir up. I was suffering with depression for over a year and it was because I had neglected Fiber. We're hearing that Fiber can even prevent other scary things, like heart disease and cancer. Yet apparently, a ton of us just aren't getting enough of it. According to National Surveys, over 90% of folks in the US aren't eating enough fiber every day.
90%! So could adding a few scoops of brand to your diet really be the thing to make you a better and brighter you? When it comes to Fiber, a lot of us want to be... ...bripping logs daily. But then, there's science. Science versus Fiber is coming up just after the break. The toilet break? This is Wendy from Science Vases. This month, our friends at Ford are the presenting sponsor of Science Vases.
If you're curious to learn more about things like electric vehicles, Science Vases is a great lesson. We dive into topics like how beavers are helping the fight against climate change, what the greenest way to die is, and what a 100% renewable future looks like. And more, listen to Science Vases on Spotify. Brought to you by Ford. This episode is brought to you by Bank of America. Money decisions. Do they really have to be either or?
Well, with Bank of America turns out, they can be yes and... ...as in, yes, to subscribing to a science journal... ...and saving up for the latest high tech year. Their digital tools help you create the future you want... ...and help you keep enjoying today too. Do more with the bank that asks, what would you like the power to do? Explore tips and more at bankofamerica.com slash yes and member FDIC. Welcome back! Today on the show, we are diving into the world of fiber... ...and to help us out.
We have producer Michelle Deng. Hi, Wendy. How cool do you think Fibres? I don't know. I'm very impressed by Fibres. I impressed by Fibres. Fibres can affect so many different parts of your body... ...that I didn't realize before. Okay. All right. Where do we begin? Okay, Wendy. The one thing that everybody knows about fiber is... It keeps you regular. Yes. Which is such a funny euphemism for it makes you do good poo's. Yes. Regular good poo's.
Now, I don't want to stay in Poo Land for too long, because surprisingly for me. But why exactly does fiber do this? So I talked to Dr. Deirdre Michelson at the University of Queensland... ...and she told me what the ideal fibery poo looks like. The sausage. That's a sausage. Indeed. That's a sausage. So you want sausages coming out of your end. Smooth and soft. That's right. Smooth and soft, because you know, it's just coming out. You're not having to force it.
So why does a good sausagey poo... ...have a bunch of fiber in it? Okay. So fibers are generally these carbs we can't digest. They basically don't get destroyed by the juices that are gut throws at them. And well, particularly think about the tough part of fruits and veggies, like the skin, or even nuts. The fiber in these make it all the way down to your poo pipe. You're lower in testosterone. Yes. And they end up adding weight and size to your poo.
Oh, because if you eat something and a low in fiber, like white bread or something, a lot of that is just going to get absorbed by your small intestine or whatever. It's not going to get all the way down to your poo pipe, as you say. Yeah. And here's the other part of it. If you zoom in on a piece of fiber, it kind of looks like a tangled ball of yarn. And in between the strands of it, that piece of fiber can entrap water. This helps you get a nice moist poo that moves along as well.
Oh, that's cool. The dry poo's. There's actually a study from the 80's where they tracked how long it took 12 people to poo after eating. And on average, fiber made their poo's faster by 24 hours. Wait, so just by eating fiber, stuff moved through their gut faster by 24 hours. So, you know, it's shaped off the whole day. Dad, that's impressive. That's impressive. Okay. Away from poo now, can we dive into these bigger claims about the gut?
Like I've heard that eating fiber can reduce the chance of you getting leaky gut. Irritable bowel syndrome. The whole in Kadsaw. Yes. To get us into all of those, you and me, we're going to start off by looking at this amazing study that Deirdery did involving pigs. Oh, okay. Wendy, I don't think we do enough pig studies on this show. Okay, okay. Well, let's bring in the pigs. So, several years ago, Deirdery and her team got 40 pigs. And these were chunky white pigs.
So, do imagine babe or Wilbur. Okay. And they used these pigs because our guts are actually pretty similar to piggy guts. So, what happened to these little little Wilbys? All these pigs got a fancy meal. We fed pigs steak. And this was good steak. This is not some crummy thing. It was barbecue, you know, steak. So, everyone got the steak as part of their diet. But half of them had a bunch more wheat fiber added to their diets too.
Okay. And they had to eat like this for a month before it was time to check on their guts. And well, to do that, these pigs were then sacrificed. The next step was for Deirdery to take a close look at what's going on in their intestines. And well, these things are really long. So, if you think about your garden hose, your green garden hose and how long that green garden hose was, that is basically what I enravelled. Next, she gently squeezed the semi-digested food out of the intestines.
And that made me go off pork for about three months. I could not eat Japanese curry or any form of curry. That'll look yellowish or whatever. Sorry, I know it's a bit gross. Yeah, it's a bit gross. Here's where Deirdery is ready to do the fun part of the experiment. She took this digested yellowy brown stuff and stuck it under a microscope. So, they reveal Deirdery's a microbiologist. So, she wants to look at what the gut bugs were up to in these pigs. So, what was going on with the gut bugs?
What did the fiber do to the gut bugs? Ooh, do you want to see pictures from her study? Yes! Oh my gosh, yes, yes, yes. So, this is what she saw under the microscope. They looked at bits of meat inside the pig guts and bits of fiber. Okay, what am I looking at? Do you see these little green dots? Yes! Yes. Those are bacteria. Oh, okay. And do you see any green dots on this piece of meat? No, they do not care about that little remnant of steak at all. Yeah. Here's Deirdery.
Interestingly, the microbes did not attach to the meat. But they were very much attached to the fiber. You could definitely see the microbes actually sticking to the fiber. You're having a feast, basically. Absolutely, they're having a feast. Let me show you the piece of fiber. Oh, whoa! Oh my gosh, they love that fiber! There's so many of them on there, right? So many of them on there. It's like a huge body. I'm trying to think, it looks like cicadas stuck in a tree.
There's so many of them and they're all up and all the crevices. What is this main for our house that these gut bugs love fiber and do not like little bits of steak? Yeah, fiber is the main food for these gut bugs. I mean, the late meat, if they have to, but it's not what they want. We know that they get more energy from fiber over meat. Oh!
And the fact that you're feeding gut bugs with fiber matters a lot because when deodorie looked at the pigs who got more fiber compared to the ones who didn't, they not only had more good gut bugs, they had this amazing variety of them too, which is super important. What is time and time again coming through in all the studies that are being done is that a healthy gut microbiome or a healthy gut microbiota is one that is stable, one that is diverse, and one that has got abundance.
This is something that I've heard from researchers is if you think about your gut like a rainforest and a healthy rainforest has lots of different animals, monkeys, cool insects, and that's a healthy rainforest. But an unhealthy rainforest is a monoculture. And that's true with your gut as well.
Yeah, and in studies and people, we also know that both eating more fiber and having a more diverse gut bug ecosystem is linked to a lower risk of chronic diseases like urinal bowel syndrome and inflammatory bowel disease. Oh, that's cool. And so what exactly are these gut bugs doing that's sort of making it gut healthy? Yeah, so there are specific kinds of bacteria that eat fiber and leave behind this chemical called short-chain fatty acids.
Oh, so the gut bugs are kind of excreting these chemicals? Yeah, and interestingly, the cells in your large intestine slurp up these acids as energy. Really? Like the stuff that gut bugs are fawning out? All gut cells actually use that for nutrients? Yes, it's very cool. And now let me tell you what happens if you don't feed your gut bugs. It's not good. And that's where I think people don't realize that they're starving their microbes.
They're starving a portion of very important part of themselves. Yeah, one thing my grobes start to do is eat each other. Doggy dog world, if you like. But that's not all. These hungry gut bugs can go after you too. They also start eating the mucin that lines the gut. Oh. Mucin is kind of like this beautiful snot that lines your gut. And it acts as a wall of defense between all the harmful stuff that's in your intestines like viruses, bad bacteria, and toxins and the rest of your body.
But if that mucin wall defense breaks down, those gut cells under the mucin might get damaged, creating little holes in your gut lining that can then let toxins into your blood and cause inflammation. On a very basic level, if you don't eat enough fiber, your gut bugs get hungry. Your once-friendly gut bugs get hungry and they can then start eating this thing that protects your gut lining and so your gut lining starts breaking down. Yeah, you might have heard it's called leaky gut.
And we've seen this happen in mice that don't get any fiber. And so studies have found that people who don't eat enough fiber have holes in their guts. Yeah, we think that's part of the reason why low fiber is linked to some of those bad gut diseases I mentioned, like inflammatory bowel disease. Okay, and then what about cancer? Well, not eating a fiber can increase the risk of colorectal cancer. In fact, deodories colleagues saw the beginning signs of this in some of the pigs.
Within a month, without fiber, and if you had the pride protein diet, you were on track to develop colorectal cancer. And that was frightening. What did they say? That the pigs you got less fiber actually had worse DNA damage in their gut cells. And why is that? Well, one reason is because fiber helps keep your gut cells happy, right? Right, right. And happy and healthy. Yes. But also, if you have a diet that's high in red meat, we know that can produce carcinogens in your gut.
And if you're not eating fiber and not pooing regularly, that means those toxins stay in the gut for longer, giving them more time to damage the DNA in gut cells. Oh, yeah. Here's dear Dree on that. You can just see the effect starkly within a month. Like, that was what was so shocking. In one review, people who ate the most fiber compared to people who ate the least fiber had a lower risk of colorectal cancer by something like a third. All right, Michelle.
I am convinced that fiber is very important for my gut, reduces my risk of colorectal cancer and all those yucky gut diseases. That is all amazing. And it helps you poo. And it helps me poo. It's something I love as well. All right, next up, can we look at these claims around fiber and depression? That eating fiber can help with your mental health. Okay, so we do know the brain and the gut talk to each other in different ways. Like, there's a big nerve that connects the gut and the brain.
Mm-hmm. And we're getting more and more evidence suggesting that our gut microbes could be pumping out stuff like neurotransmitters that can chat with our brain. Mm-hmm. Here's John Cron, a neuroscientist from University College, Cork, in Ireland. So, our gut talks to our brain, but our brain talks to our gut. Two-way streets.
And when it comes to why fiber in particular might help your brain, do you remember how when you eat fiber, certain gut bugs will eat that up and make those short-chain fatty acids? Yes. Well, we think that those can travel through our blood to the brain and possibly help how neurons communicate with each other. Oh. So, recently, John took fresh brain slices from mice and doused them with those chemicals that microbes make. Mm-hmm.
And what he saw was that these chemicals could affect synaptic plasticity, which is how neurons can change their connections between each other. That's what helps us make memories and learn stuff. And John says it also might be helpful in treating depression. So, here's how John thinks about fiber. I think it is the fuel for your micro-factory. It is fuel, and it's fuel for your brain.
So, if there have been any studies in people to really test this out, this idea that fiber can reduce depression. Okay, so there are studies that have asked thousands of people about how much fiber they eat and separately what their mental health is like. And they generally do find a link between low fiber and depression and anxiety. That's interesting. Studies like this led to a lot of exciting headlines. I'm sure. Quote, the key to reducing your depression risk could be fiber, study says.
That quote. I guess with those studies though, it is impossible to know if it was the fiber that caused the boost in mental health. Because fiber, eating a lot of fiber generally comes with a generally more healthy diet of eating fruits and vegetables. And there's lots of reasons why if you already have depression, you might not be eating a healthy diet. Yes, it's hard to know in those types of studies. If it's really fiber, making a difference here versus other stuff going on in their lives.
Exactly. And so to get to causation, we need our favorite randomized controlled trials. Or researchers randomly assign people to take a hill fold with fiber and see if it improves their mental health compared to a control that gets a placebo. Great. Okay, okay. So what are these studies find? In this big meta analysis that John was a part of, they looked at 10 of these studies and only two found it worked. The rest of the eight studies didn't.
Yeah. And the results of the meta analysis, they said quote, no difference was found between fiber supplementation and placebo for depressive or anxiety outcomes. Yeah. Disappointing though, what would be nice if fiber was the cadia mental health? I asked John about it. The bottom line for depression is like right right now, the evidence for fiber isn't there. Yeah, absolutely. Okay. But that doesn't mean it won't work. Wait, why is he saying that?
I mean, one reason is that these studies kind of reduce fiber down to a pill. Whereas some researchers say that eating fiber from a bunch of different foods is what will make gut bugs happier. Okay. And maybe we need to be doing these studies while we're telling people to eat a big fiber filled diet instead of just taking a small supplement. After the break, weight loss can fiber help you shed those pounds? Plus how fiber might even save your life coming up.
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Introducing the all-new Apple Watch Series 10, now available for the first time in glossy jet black aluminum. Compared to previous generation, iPhone XS are later required. Charge time and actual results will vary. Welcome back today on the show. We are talking about the wonders of fiber. You thought it was just your grandfathers cereal, but in fact, the fiber is getting a glow up. We're here with producer Michelle Dang and now we're going to the heart.
We think fiber might actually be a lifesaver here. Interesting. How does this work? Yeah. So we've kind of been talking about fiber as one thing. It actually breaks down into a couple different types. So there's soluble fiber and insoluble fiber. And within the soluble type, you've got stuff that turns into kind of a gel. Sticky. We call it sticky fiber sometimes, the viscous fiber. This is Andrea Glenn. She's a nutrition scientist at New York University.
And I asked Andrea about where we find viscous fiber in the first place. You think of like oatmeal? Like if you're playing with cooked oatmeal, it's going to stick to your hands and that's the viscous fiber. Have you ever eaten okra before? And it's kind of jelly. Limey. Yeah. Yeah. So that's also viscous fiber. So yeah, it's in a bunch of stuff like fruit, eggplant, mushrooms, beans, for example. And when it continues to mix with water in your stomach, the gel gets even thicker.
And so then how is that good for your heart? Well, it starts here. So a big reason that people develop heart disease is because eating sugar and fun stuff like muffins, candy can give you high blood sugar spikes. Right. And if that happens over and over again, you can get insulin resistance, which can then lead to diabetes or even heart disease. And what's super cool is that sticky fiber can help stop those high sugar spikes. How? Because when you eat food, that becomes that thick gooey stuff.
But that does is it slows down digestion. So it stays in your stomach longer. You know, because it's like physically sticky and heavy. In one study, they fed people five grams of gorgum, a viscous fiber with a meal, and found that it slowed down food going from the stomach to the small intestine by nearly two hours. But didn't it make us poo foster? Now it's making us poo slower. Because this because it makes us poo foster, what's the food gets into the larger test it.
But now this, all this fun action is happening to higher up in the god. Yeah, exactly. It's specifically slowing down the emptying of your stomach into your small intestine. And this is important because your small intestine is where sugars get sucked up into your blood.
Oh. And not only does it slow down food, this goopy sticky gel is also coating up all the foods that you be in with it, creating this barrier around it and making it harder for a little digestive enzymes to reach the sugars you be in. So it means less sugar gets into your blood? Not that, but it does mean that sugar gets into your blood slower. Oh, because it's protected by this goop. Right. It makes it harder for your gut to slurp out sugars from the food you be in.
And suck it up into your blood. So your blood sugar goes up slower and then it goes down slower as well. So if we ate an apple with a gummy bear, what happened then? Yeah, it would be better than just the gummy bear on its own, but does it cancel out or the sugar? No, definitely not. Okay. It's probably, but it actually does help a little because it slows down the sugar spikes, right? And then I also want to tell you quickly about cholesterol because fiber helps with that too.
Huh. Right. Okay. So it's a very weird journey. So the sticky fiber comes along and traps these things called bile acids in our guts, which are there to help us digest food. Uh-huh. But this means that your body needs to make more and more bile acids. And what's important for a story here is that bile acids are made up of cholesterol.
Oh. Yeah. So because the sticky fiber is trapping your bile acids, basically taking them out of commission, your body has to make more and more and more bile acids, which means it's sucking up more and more cholesterol from your blood. And that is how eating fiber reduces cholesterol? Yes. Very tricky, right? It's like, what? That is very surprising. So does eating this viscous sticky fiber have a measurable effect on the risk of heart disease?
Yeah. So recently, Andrea did a study to find out like, what are the long term effects here? Yeah. And she used data of more than 200,000 people that have been tracked for about 30 years. And what they found was that people who eat a fiber pack diet had a 14% lower risk of total cardiovascular disease, coronary heart disease. So that includes things like heart attacks and then stroke as well. That might not all be because of the fiber though, right?
Because like we mentioned, if you're eating a healthy diet, you might also be doing things like more exercise or other stuff. That's true. That's true. But Andrea thinks it's real. And Andrea could see in the data that the more viscous fiber people ate, the better it was. Cool. Actually, there's a bunch of studies that have found this over and over again.
There's even one man analysis that found that for every 10 grams of fiber people ate a day, it brought down their general risk of dying by 10%. So that's pretty simple. Okay. Fiver. Can help you live longer. All right. That wasn't a raise it enough to ate fiber. The last thing we're going to look at is this claim around weight loss. So what do we know here? Okay. So this viscous fiber moves pretty slowly through your stomach and into your gut, which also means you might not get hungry as fast.
So if you're, you eat like a bowl oatmeal and you don't need to eat for five hours versus like white bread, maybe you'll be hungry again in two hours. And you'll have an extra snack so it might help control your calories that way. That makes sense. And there's also some evidence that fiber helps with weight loss because of those gut bugs. When they munch up the fiber they love so much, they actually help your body pump out hormones that could help you feel fuller. Oh, cool.
But let's look at what happens to people's weight when they actually have more fiber. One study actually had people take this super viscous fiber for a year and they lost some weight, but it was less than three kilos about six pounds compared to a control. And in fact, a big meta-analysis looking at more than 60 trials found that people on fiber compared to control diets on average. They lost about 0.3 of a kilogram. Oh. So it's not a lot. It's not so much at all, it's not less than a pound.
Oh, that's so low. That's so low. I guess that classic thing of just eating is complicated. And even if that bowl of oatmeal made you feel more full, it doesn't mean 30 minutes later you're not reaching for the chocolate. Yeah, I'm speaking for myself, personally. Okay. So even though fiber, not particularly good for weight loss, it is good for so many other amazing things. Your heart, your gut, and yet 90% of us aren't getting enough of this. So what does it take to eat enough fiber?
Well, Wendy, I had you track your fiber. Yes. Let's look at how you hold up to what you're supposed to be eating. I wondered when that was coming into it, yes. And let me tell you first, the recommended amounts to eat, it's about 25 grams for woman and 30 grams for men. Okay. More or less depending on your age. If I look at your data, there were two days out of 14 that you hit your recommended amount. That's it. But on those days you did really good. You got over 40 grams of fiber on the days.
You bet it. But then on the rest of the days you were around like 15, 16 grams, which actually is where most of us are eating on average. All right. This is an example of an average person who did not reach their fiber. I guess I'll just go through the stuff that has fiber in it because I ate a little bit of it, I ate a bagel, I ate an apple scroll, garbage calories, right? I ate half a tomato, two apples, half a carrot, some lettuce, some walnuts, that didn't get me that. And I tracked you.
I did not do a very good job. So I know the struggle, especially when things aren't moving along, I talk to DeerDrie about this too. So when I bring out the salient musk, yeah. Oh goodness me. I had listened, do you really want to have salient musk stirred into a glass of water? It would taste disgusting. Just the, you're very immeagable. Just the accelerary with a peanut butter girl. You love that.
That's funny because like looking at that day where I ate a lot of fiber, it was because I ate two cups of frozen peas. This is my ticket, my personal ticket. Because I don't know, peanut butter just doesn't do it for me. But frozen peas, two cups will get you almost 15 grams. That's like a lot of the way there. That's my ticket to fiber heaven. That's a bowl full of peas. But that's a lot of fiber food. Now, now I think about it. The next day I actually didn't feel great. I was pretty bloated.
My foods were not the sausages. So I guess you can go over for it. Yeah, that can happen. If you eat too much fiber suddenly, it can make you bloated and farty. So you might want to ramp up the peas more slowly. But still, but still, I mean, for the most of the time I wasn't doing that, which was you on ticket to fiber town. I got 25 grams of fiber from just eating tortilla wraps. No way. So maybe that, maybe I'll just keep eating burritos all the time. That's awesome.
Was it like high fiber wraps? Yeah, they were. But again, it's best to get your fiber from a variety of foods. Yes. Other tickets to high fiber heaven could be stuff like raspberries, whole grain pasta, lentils, beans, chia seeds. And you know, why not throw in some high fiber wraps? Yeah. Right. Okay. Well, to high fiber wrap up this episode here, Michelle, here is what I have learned about fiber. It is amazing for your gut.
Guess I kind of knew that before, but now I know that if you don't have fiber, your lovely gut bugs will turn on you and start eating you and that could be bad for your gut fiber. Also amazing for your heart, particularly that viscous sticky fiber that you get from oatmeal and eggplants and okra. Not particularly great for weight loss and depression, who knows. So Michelle, you've been just swimming in the world of fiber pages. How do you think this is going to change your life this episode?
How has science versus changed your life, Michelle? It's making me be more conscious about what foods I'm selecting and I'm really thinking, oh my gosh, there's all these, these trillions of microbes in my gut that I need to feed. I'm like, whoa. So yeah, I am going to change how to eat and to take it home, here's what Deirdre had to say. Fiber is not a sexy sounding word by any stretch of the imagination, but what is sexy? Sexy is what clever marketing executives put out, right?
To promote foods for our big multinational food companies. So to help with sexy, I'm sexy, God damn it. So yeah, I'm going to look after myself and hence it means looking after my microbes and guess what, that's your five before you. Happy gut bugs, happy you. Happy you indeed, Michelle. And I think on that note, I think that's a wrap. No, sorry, that should be your thing. No, but that's exactly that is so well put. All right, Deirdre said it. That's a wrap.
And Michelle, how many citations are in this week's episode? There are 104 citations in this episode. And 104 citations and if people want to read more about Fiber and see these citations, where should they go? Please check out our transcript, which you can find in our show notes.
Yes, and if you want to see all of the different kinds of foods that you can eat to hit your Fiber target and reach high fiber heaven, just go onto our Instagram, science, I'll just go Vs and we've got some diagrams waiting for you. You can also say hello on my TikTok, which is at Wendy Zookaman and let me know what you thought of this episode. Thanks so much for sharing. Thanks, Wendy.
This episode was produced by Michelle Dang with help from me, Wendy Zookaman, Merrill Horn, Rose Rimler and Aketty Foster Keys. We're edited by Blav Torell, fact checking by Erica Akiko Howard, Mix and Sound Design by Sam Behr. He's written by Bobby Lorde, Peter Leonard and Boomi Hedakka, recording help from Nick Kilvert and extra thanks to Cafe at Yusuf. Plus, thank you to Joseph Lavell Wilson and the Zookaman family. ScienceBest is a Spotify Studios original.
Listen to us for free on Spotify or wherever you get your podcasts. We are everywhere. But if you are listening on Spotify, follow us and tap the bell icon for more episode notifications. So you know when new episodes come out, like this one. I'm Wendy Zookaman, back to you next time. This episode of ScienceFest is brought to you by Ford. There are a few pickups more iconic than the F-150. And the 2024 F-150 Lightning Truck is no exception.
With an EPA-estimated range of 320 miles with the available extended range battery, it's the only EV that's an F-150. Visit Ford.com to learn more. Excludes Platinum models, EPA-estimated driving range based on full charge, actual driving range varies with conditions such as external environment, vehicle use, vehicle maintenance, high voltage battery age and state of health.