Science Vs - Probiotics: Scam or Superfood?

Episode Date: August 27, 2020

Kombucha, kefir and other probiotic-crammed foods are marketed as charmers of the human microbiome — and the key to immune, gut and brain health. But how much does the microbiome actually matter, and do probiotics live up to the hype? To learn more we talked with biomedical engineering professor Ilana Brito, immunologist Dr. Yasmine Belkaid, psychiatry professor Ted Dinan, and microbiologist Dr. Namrata Iyer. UPDATE 8/28/20: An earlier version of this episode said there was a little bit of evidence that specific microbes can help with irritable bowel disease. This should have been inflammatory bowel disease. Here’s a link to our transcript: https://bit.ly/34ElmvR This episode was produced by Wendy Zukerman, with help from Nicholas DelRose, Rose Rimler, Meryl Horn, Michelle Dang, Sinduja Srinivasan, and Hannah Harris Green. We’re edited by Blythe Terrell. Fact checking by Diane Kelly. Mix and sound design by Peter Leonard. Music written by Peter Leonard, Marcus Bagala, Emma Munger, and Bobby Lord. A huge thanks to all the researchers we got in touch with for this episode, including Professor Martin J Blaser, Dr Kirsten Berding Harold, Professor Andrew Holmes, Professor Eran Elinav, Professor Margaret J. Morris, Professor Tim Spector, Professor Dena Lyra, Professor Eric Alms, Dr Joel Babdor, Joana de Cruz Pereira, Josh Jones and all the others. And special thanks to Walter Rimler, the Zukerman family and Joseph Lavelle Wilson. Learn more about your ad choices. Visit podcastchoices.com/adchoices

Hi, I'm Wendy Zuckerman and you're listening to Science Versus from Gimlet. We are back with a brand new season. And today we are pitting facts against feces as we dive into the science of the gut. Over the last few years, we've been hearing more and more about all the gut bugs that live in our belly and how important they are for our health. And these days, it's like you can't open up Instagram or grab a shopping trolley without seeing some product saying it'll fix up your gut bugs and keep you healthy. So I went out to the supermarket to hunt for these products that are

promising to help me with my gut. Do-do-do-do-do. My gut. Do-do-do-do-do-do. Alright, I'm heading in. We've got kefir here. Referred to in ancient texts, kefir is more than a probiotic superfood. Kimchi? It's a fermented superfood.

Now we're in the kombucha section. With billions of living probiotics, supports digestive health. Sauerkraut. And on the back it says, gut smart and just plain good. And it's not like this stuff is new. It just has a sparkling new image. Like, when my great-grandparents were buying sauerkraut in the old country, they weren't saying it was a probiotic superfood.

But still, at the shops, I wasn't done yet. There were still the bottles of probiotic pills. Supports healthy digestion. Helps digestion after meals. There's a lot of digestion. Promotes regular, healthy and comfortable movements. They're talking about poo. And it wasn't all about my poo.

Some products were saying they could keep my brain healthy and even help my immune system. How would that work? And that's what we'll be digging into today. Because the wellness industrial complex says that you should be taking probiotics every day, like a vitamin. These companies say that their products are chock full of bugs that can supercharge your gut and put you in the peak of health. And the thing is, we do know that there are tons of bacteria, viruses, fungi and other stuff happily living in our gut and on our body. So, can all those bugs living in us be that important?

And can these products really help you out? When it comes to the gut, there's a lot of probiotic superfood. But then there's science. Science versus the gut and all the creatures inside it. Coming up after the break. Y'all afraid of ghosts? How about ghost peppers? It's the moment you've been waiting for the ghost pepper sandwich is back at popeyes a buttermilk battered chicken breast served on a brioche bun with barrel cured pickles and here's the best part it's topped with a sauce made from ghost peppers and oncho chilies if that doesn't send a chill of anticipation down your spine nothing will

get your ghost pepper sandwich today at Popeyes before it ghosts you for another year. So I first came to Edward Jones with a great deal of trepidation when I first met with my advisor and I really was feeling vulnerable about what I would have to share. I was of course pleasantly surprised to find that there was absolutely no judgment and a lot of support. And when it was time to get serious, he really took my hand and helped me to do that. Edward Jones. We do money differently. Visit edwardjones.ca slash different. Bumble knows it's hard to start conversations. Hey. No, too basic. Hi there. Still no.

What about hello, handsome? Who knew you could give yourself the ick? That's why Bumble is changing how you start conversations. You can now make the first move or not. With opening moves, you simply choose a question to be automatically sent to your matches. Then sit back and let your matches start the chat. Download Bumble and try it for yourself. Welcome back. Today, we're getting down and dirty with our gut bugs and working out what you can do to keep yours healthy. So there's all these bacteria and other little tackers in and on our

body. Collectively, they're known as the microbiome. And basically, from the time we're born, these bugs just jump all over us. You can get them from your mom's vagina, your dad's skin, from your environment, from the food you eat, and there's just a lot of them. I mean, in total, there are trillions and trillions of organisms in our gut. This is Alana Brito, a lot of them. I mean, in total, there are trillions and trillions of organisms in our gut. This is Alana Brito, a professor of biomedical engineering at Cornell University. And Alana says that while most of these microbes live in our gut, you can also find them elsewhere. We have a lot, a lot of microbes that live in our mouths,

and especially like around our gums, and they're totally different than the organisms that you find in the gut. They're almost like different habitats in the world. Like one is like a, you know, a rainforest and another one is like a tundra. And what science has come to realize is that all these bugs, they aren't just lazing about. They're hard at work. So let's zoom into what they're doing in your gut. Because funnily enough, this is kind of what the marketing hype gets right. On a scale of one to ten, how important is the microbiome to a healthy gut? Oh, I mean, I would put it up there. I would put it at a nine or ten. We definitely need them. So we know that when we eat certain foods, bacteria in our gut can mulch them up and then spit out these products called fatty acids, which do a bunch of things.

Like, they help our metabolism and repair cells lining our gut. Another thing that gut bugs can do? They can actually directly synthesize vitamins for us. What? Yeah. Bacteria in our gut can make B vitamins and vitamin K. And so why is the bacteria going to all this trouble? I mean, it's just them making a living. So they're just, I mean, we basically benefit from their byproducts.

I love that, like where, I love how you put it that we are benefiting from their byproducts. Like, I feel like we're so humancentered in the way that we view it, but actually we're just benefiting like from their poo in a way. Yeah, just like they're benefiting from ours. Right. And to Alana, the fact that gut bugs are doing all this stuff for us, it kind of makes sense when you think about the fact that we evolved alongside these tiny critters ever since we were tiny critters.

And now, we're basically a ball of human and microbe cells. So after all of these, you know, millions of years of evolution, we've figured out these ways of surviving together and helping one another out so that we can all live happily ever after, pretty much. And it's just, you know, we're just learning about all of the different things that they can do. I kind of feel like these bacteria have superpowers. So that's just some of the superpowers of the bacteria in our gut. They're making vitamins for us and pumping out fatty acids. But just how powerful

can these bugs really be? Next, we're going to dive into this other big idea that's being flaunted about our microbiome, that it can work wonders for our immune system. How would that work? To find out more, I went on a trip to Bethesda, Maryland. This was before the coronavirus. I'm here at the National Institutes of Health. Time for science. Science, science. Oh, yeah.

Hi. Hello. Hi, how are you doing? Hi, I'm Wendy. This is Dr Yasmin Belkade. She's an immunologist who came to the NIH a couple of decades ago from Algeria via France. And she fell in love. So when I first arrived, it was actually like a candy store. I mean, this place is amazing.

I mean, you had enormous amount of research. All fields were represented. People came from all around the planet. I thought it was the best place on Earth. Yeah, Yasmin is possibly the first person ever to refer to Bethesda, Maryland as the best place on earth. But she's a massive nerd. And I came to see Yasmin because she heads up this lab that has one of the best tools that scientists have to unravel the mysteries of the microbiome. It's germ-free mice.

That is, mice that have been created with basically no microbiome. It's germ-free mice. That is, mice that have been created with basically no microbiome. And scientists create these mice to see what happens in the body when all the bugs are gone. The only problem is that making these mice is tricky because bugs are everywhere. They're in the air, on the ground, in our food.

You may not realise, but there is numerous microbes flying around us right now, ready to actually contaminate. They also cover us from the moment we're born. So how the devil do you do this? That is... So how do you make a mice that is germ-free? Well, it has to start from the moment the mice are born. Researchers don't want them to pick up microbes from a mousy mum's vagina

because the vagina of a mouse mum, and your mum, by the way, is teeming with bacteria. So, instead, they do little tiny mouse C-sections. These can actually be maintained sterile because they can actually be collected sterilely. Then they give the mouse babies to a mum that's also germ-free. It all sounds like a chapter from a hand-mouse tale. From here, Yasmin's task is to create an artificial world

with no microbes. I got a peek inside. Hello. Hello. No microbes. I got a peek inside. Yasmin took me inside a room with basically a very hot giant oven. Which is not very glamorous, but it's an autoclave. It's called an autoclave. And before stuff gets anywhere near the mice, it has to be popped inside this autoclave to kill off any possible germs. The food, the water, the bedding, the cages, everything needs to be autoclaved.

All those things get wrapped up and taken across the hall to where these squeaky clean germ-free mice live. So we're about to head into the facility where the mice have no germs. Whoa, I almost did it. I almost ruined everything. Whoopsie. I need some protective gear because I'm full of bacteria. As you can see, we're all

wearing masks, hats and the lab coats. Good. Okay. We walk into the room with the mice and the first thing I notice are the cages. They're not normal. These are these bubbles. They kind of look like an aquarium made of flexible plastic.

A big plastic bubble on this kind of bizarre white table with a lot of, like, cylinders and things around. So what you see inside is completely sterile. And how do they breathe in the bubble? How do they breathe clean, non-germy air? It's entirely filtered. These bubbles have to be maintained in a perfect condition. A tiny hole that would be with a needle will destroy an entire experiment.

OK, so that's what it takes to get yourself a germ-free mouse. And the thing is, these little beasties, they look like regular mice. Completely fine and happy. In fact, very shiny fur and be running around like happy little mice. But when scientists like Yasmin investigate these mice closer, they don't seem like such happy little healthy mice. Here's how Alana Brito described them. They're very weird.

Like their intestinal lining doesn't look healthy. It doesn't have all the nice folds that we have or that a healthy mouse has. They don't produce the same type of mucus that we produce. Like their immune system's all weird and out of whack. They're just, they're not healthy for sure. That is, they don't have a proper immune system. Like without microbes, germ- is, they don't have a proper immune system.

Like without microbes, germ-free mice just don't pump out as many white blood cells as they should. Those are the soldiers of the immune system. And while healthy mice have little bundles of tissue in their small intestine packed with immune cells, these germ-free mice, those little bundles never develop fully. And all of this means that our germ-free mousies can really struggle to fight off some infections. So, for example, in one experiment, it took just a teeny tiny dose of a particular salmonella bug to kill a bunch of them.

So from these mice, we know that you can live without a microbiome. But you can live in a bubble. You can live in a bubble. Yeah. If you want to live in the real world, you need microbiome. Exactly. So how is this possible? Like, how on earth could not having germs,

the thing we've been told to keep out of our body, be so important that without them, the immune system've been told to keep out of our body, be so important that without them, the immune system of these mice doesn't develop properly? Well, for one thing, when you have a microbiome, friendly bacteria can take up space that unfriendly bacteria might otherwise colonize. But something else is going on here too. We're now realizing that some bacteria act like little life coaches for the mouse's immune system. That is, they send out signals nudging the body to make immune cells. To Yasmin, it's like the microbiome and the immune system are having a conversation. But I mean, the word conversation is the right one.

They are constantly dialoguing and they're talking back and forth. Like some bacteria have this little tail that whips around, helping them move. And as these bugs get around, they chat to certain immune cells, tickling them and getting them to create an immune reaction that helps fight off dangerous bacteria. I think it's super cool. It's absolutely fascinating to think that the microbes are able to actually manipulate the immune system

in a way that protects the host. Why would they do that? Well, we are home. So you actually want to preserve your home. Now, a lot of gut bug science comes from mouse studies. We don't have these kinds of experiments in humans since we don't go around wiping out people's microbiome. What we do have, though, are studies on what happens when people take antibiotics. So as you might know, when you take these meds to kill bad bugs, it also kills

some good bugs. And studies have found that taking antibiotics as an adult can increase your risk of getting nasty infections. And if you give babies antibiotics, they're more likely to get asthma and allergies when they're kids, which is a sign of an out-of-whack immune system. A big review paper on this topic said that by keeping our immune system healthy, preventing nasty bugs from invading and doing other stuff, gut bugs have, quote,

far-reaching impacts on human health, end quote. So far, the microbiome is sure living up to its hype. After the break, we look at the weird ways that gut bugs might affect your mind, and whether downing kombucha or probiotic pills will keep these gut bugs happy. Welcome back. From everything we've heard so far, the microbiome is kind of a big deal. It's the Scotty Pippin to our body's Michael Jordan. Underpaid and underappreciated, at least when it comes to the gut and our immune system. But what about the brain?

Some of these products are claiming they can boost your mood and even help with depression. Is that true? Or this time, will the microbiome foul out? Hello, good morning to you. Ted here. This is Ted Dinan. He's a psychiatrist at the University College Cork in Ireland. And several years ago, Ted led a study that kind of rocked the world of microbes. You see, Ted had been working with depressed patients for decades,

and some of them were really tough to treat. These patients were describing intense sadness. They weren't enjoying life to the extent that they would have previously. Most of them were quite anxious. These patients had the kind of depression that wasn't getting better with treatment. Ted had been reading and doing his own research into the newfound powers of the microbiome. And he wanted to know, could the microbiome have something to do

with his patient's depression? And so one day, he asked them for, well... A sample of poo, basically. I mean, an early morning sample of faeces. Early morning, because you knew you could get the early morning one. Yeah. OK, he actually did it to keep the samples consistent. But anyway, so Ted wanted to see if it was even plausible

that some of the gut bugs in the poo could affect the brain, any brain. So we did a fecal transplant from humans into rats. How do you transfer human poo into a rat? Okay, it's not difficult because rats are by nature coprophagic. In other words, they eat feces. They eat their own, they'll eat other rats' feces. So it's just the natural behaviour of a rat. So we took the human poo and popped it in the rat's cage.

They just simply ate it. They just gobble it up. Yeah, exactly. And that then became their microbiota. A week later, Ted went back to the rats and put them through some tests to see if they were acting any different. When we looked at the behaviour of animals, their behaviour altered and they just seemed to develop depressive-type behaviours.

How do we know that the rat is depressed? Like, you know, does it start watching, you know, season five of The Good Wife or something? Well, yeah, rats are normally, first of all, they're social creatures. They tend to interact with other rats. They also tend to be quite exploratory. They will explore any environment they're in. But when Ted gave these rats a little maze to go exploring in,

they weren't too interested in it. And Ted noticed that they were also hanging out with their friends less. And he was surprised. I was. I was very surprised. And no, these rats weren't just sick or depressed because they were having to eat poo. Because when he gave rats poo from people who weren't depressed, they seemed totally normal.

Another team of researchers basically repeated Ted's experiment but in mice and found the same thing. And all this led Ted to wonder. What is it that the microbiome does normally that is good for our mood? In other words, I mean, if a bad microbiome is bad for our mood, what is the normal microbiome? What is that doing? Well, we know that a burst of certain chemicals in our brain, like from serotonin, can affect our mood. And here's the thing. A swell of research in Petri dishes is showing that certain bacteria found in our gut

can also make those chemicals, which are called neurotransmitters. The gut microbiota is capable of producing every human neurotransmitter that we currently know of. Whoa! Certain gut bugs can literally pump out serotonin, while others make chemicals that are later transformed into these neurotransmitters.

Now, it's not entirely clear whether these so-called happy chemicals in our gut affect our brain, because we don't think that they can swim from your gut up into your noggin. But they actually don't have to, because there's tons of nerves around your gut that connect up into the brain via the vagus nerve. So these gut chemicals, they might be poking those nerves and sending signals up into the brain that way.

Now, depression has shown itself to be a tricky beast to study in humans. So it's really not clear how important these gut bugs are to people with depression. A lot of the research is in rodents. But for now, Ted is excited about the possibilities. This gut-brain connection has opened up a door that's been closed for a while now. Well, I think, you know, the study of the biology of mental illness has been in a bit of a rut for a long, long time. There have been no new drugs coming along. And I think that the brain got microbiota access is a new paradigm. It's a new way of looking at mental health. So in that sense, I think it is a game changer. So while we're still working out a lot of details about the microbiome's superpowers,

we do think that these bugs are super important for our health. So our final question is this. We know a happy microbiome is key to keeping us healthy. But how do we get one? We know a happy microbiome is key to keeping us healthy. But how do we get one? There's all this stuff promising to give us a better microbiome, from kombucha to kimchi, sea moss to sauerkraut, pickles to probiotic pills. Are they onto something?

Well, there's a little bit of evidence that specific microbes can help with certain ailments. And if you're taking antibiotics, there's actually mixed research on whether downing probiotics can help you at all. But just generally, I'd say the studies here are pretty underwhelming. And there's a bunch of reasons why probiotics aren't the amazing medicine that they're claimed to be. A big thing is that there are thousands of different species in our body. And for the most part, we don't know which concoction of bugs might help with which illnesses. So take mental health, for example. Scientists like Ted run these clinical trials in people

testing different species of bugs. And sure, some show promise, but not all. Absolutely. I mean, we've tested lots of different bacteria and most bacteria do not have an impact on mental health. You know, I suppose to be a strange situation if, you know, if we have a thousand strain of bacteria in our intestine to be pretty strange if all of them had a major mental health benefit. And the odds that the stuff on the supermarket shelf, be it the bugs in kombucha, yogurt, in our intestine to be pretty strange if all of them had a major mental health benefit. And the odds that the stuff on the supermarket shelf, be it the bugs in kombucha, yogurt, or probiotic pills, are the secret ingredient that's going to mend your microbiome?

It's pretty small. In fact, a lot of products with probiotics have the same handful of bugs in them. It's stuff like lactobacillus acidophilus. And that's like Lactobacillus acidophilus. And that's not because Lactobacillus acidophilus has some amazingly wonderful bacterial property. It's because we've been eating it in stuff like yogurt for a really, really long time. And so the FDA has said, it's not dangerous to eat. You can shove it in food or pills if you want. I would warn listeners that most bacteria that are on the shelves in health food stores and, you know, available elsewhere have no data behind them whatsoever. Companies make outlandish claims for which they have very little data often or sometimes no data at all. Do you use probiotics? No, they're sort of a sore point for me. Oh, really? That's Dr. Namrata Iyer over at Trinity College in Ireland.

I don't use probiotics, no, I think. And she gave us one important final reason why you wouldn't need to guzzle probiotics in pills or in food if you're healthy. You see, from what we know, Namrata says that what makes a healthy gut is the fact that it has a diverse microbiome. So one that's full of different kinds of bacteria, viruses and fungi. She says that we should think of our microbiome as a rainforest. And you have trees and you have tons of animals and you have insects and all of that.

Yeah, there's toucans, monkeys, sloths, turquoise brown bot-bots. It's the kind of bird they make this noise. Do you hear it? It's kind of like a... Anyway, the point is that a rainforest is way healthier and resilient to disease than, say, a field of corn. And Amrata's like, taking these probiotics, it's like... If you try and just introduce one thing,

like, say, a bird or something... Throw in an extra mop-mop to your beautiful rainforest? Big whoop. a bird or something. Throwing an extra mop mop to your beautiful rainforest? Big work. Yeah, they wouldn't change that ecosystem in any noticeable way. There's just so much excitement amongst people about the power of the microbiome and what it could mean for quality of life and therapies. And it's, I mean, it's all true. The potential is enormous, but I feel like the probiotic market has sort of tried to cash in on that prematurely. It's sort of the perfect storm for marketing hype.

You know, on one hand you have, you know, genuinely exciting research showing that the microbiome plays this integral role in our health in so many, possibly, possibly so many aspects of our health. But the science is not there to show how we give ourselves the perfect microbiome. So there's this big vacuum and enter the probiotics, enter the kombucha bottles. It's just perfect. You couldn't create like a better scenario for a fad, basically. Exactly. And I mean, I grew up eating yogurt every day of my life and it's the best. Like kimchi is super tasty and kombucha looks a little gross to me, but people love it.

But if you start selling bottles of stuff that say we have live bacteria and it claims to cure like five different things, then that's just misleading. So if probiotics aren't the cure, what can you do for a healthy gut? Well, here's one thing that's popping up in the literature, a hot tip. And here it is. Lean in close and raise the volume on your headphones because it is just so groundbreaking that I'm going to whisper it. Eat fruits and veggies and whole grains.

And the reason that eating that stuff is good is because it's full of fibres, and the bacteria already in your gut love to eat it. So when you munch on an apple, it's like sunshine and rain for your inner forest. Studies have found that eating more fiber, essentially feeding your gut bugs, is linked to a more diverse microbiome. And every scientist I spoke to agreed on this fiber point. Absolutely. I eat a lot of kale every morning,

and I sometimes think that, you know, my microbes are happy with that because it's high in fiber, and microbes love fiber. Eating a healthy diet with a lot of fibers is really fundamental. It always comes back to that, doesn't it? At the end of the day, we're going to do all this fantastic research, all of us, and at the end, we're excited too and as part of it we'd love to hear your stories any tales of unexpected first or non-existent orgasms or if it's always been easy for you to get one we we want to hear stories about that too. You can be totally anonymous.

Just call 774-481-1238 and leave a message if you're in the US. Or you can record us a voice memo and send it to scienceverses, that's science vs, at gimletmedia.com. Thank you. Hello? Hey, Nick Delrose, intern at Science Versus. Hey. So how many citations in this week's episode?

There are 121 citations. 121. I know. Oh my gosh. And if people want to see these citations, find out more, where should they go? They can follow the link in our show notes to our transcript. Great. Thanks, Nick.

Yep. How was your very first citations? How did it go? It went mediocre. I think it went great. All right, bye. Bye. This episode was produced by me, Wendy Zuckerman,

with help from Nicholas Del Rose, Rose Rimler, Meryl Horn, Michelle Zhang, Sindhuja Srinivasan and Hannah Harris-Green. We're edited by Blythe Terrell. Fact-checking by Diane Kelly. Mix and sound design by Peter Leonard. Music written by Peter Leonard, Marcus Begala, Emma Munger

and Bobby Lord. A huge thanks to all the researchers we got in touch with for this episode, including Professor Martin J. Blazer, Dr. Kristen Burding-Harold,

Professor Andrew Holmes, Professor Iran Elinav, Professor Margaret J. Morris, Professor Tim Spector, Professor Dina Lyra, Professor Eric Arms, Dr. Joel Babdler, the Zuckerman family, and Joseph Lavelle Wilson. I'm Wendy Zuckerman. I'll talk to you next week.