The Art of Manliness - The Microbiome Master Key — How 100 Trillion Bacteria Influence Your Weight, Mood, and All-Around Health

00:00:00.000 Brett McKay here, and welcome to another edition of the Art of Manliness podcast.

00:00:11.460 When you think of the microbiome, you probably think of your gut, but bacteria live all over

00:00:16.100 your body, and they're incredibly numerous. You play host to about as many microbes,

00:00:20.900 100 trillion of them, as you do human cells. As my guest will explain, these microbial ecosystems

00:00:26.560 are not only ubiquitous, but hugely influential for your health, impacting everything from your

00:00:31.280 weight and mood to your risk of developing many diseases. Dr. Brett Finlay is a microbiologist

00:00:36.480 and the co-author of The Microbiome Master Key. Today on the show, Brett explains what the microbiome is,

00:00:42.160 how modern life, including our overemphasis on hygiene, has damaged it, and how the quality

00:00:46.280 of your microbiome is connected to nine of the top 10 leading causes of death, as well as everything

00:00:50.720 from depression to Parkinson's. Brett also shares how we can boost the health of our microbiome,

00:00:54.740 including whether probiotic supplements are effective, how something as simple as flossing

00:00:58.740 your teeth can cut your risk of Alzheimer's by 50%, and why you might want to let your dog lick 0.58

00:01:03.160 you in the face. After the show's over, check out our show notes at aom.is slash microbiome.

00:01:16.020 All right, Brett Finlay, welcome to the show.

00:01:22.840 Hey, thanks for having me.

00:01:23.600 So you are a microbiologist and you study how microbes can cause disease in us, but also you've

00:01:30.840 done a lot of writing and research and education on our microbiome that we all have inside of us,

00:01:38.460 on us. We'll talk about that as well. I'm sure a lot of people have heard of the microbiome. They

00:01:43.880 may be seeing advertisements for supplements or even food that's supposed to help your microbiome.

00:01:49.920 But I imagine if you asked a lot of people, like, what is the microbiome? And they'd be like, oh,

00:01:54.420 kind of hem and haw. So let's start with this question. What is the microbiome?

00:01:58.560 That's a good question. Basically, it's a collection of all the microbes living in and

00:02:05.260 on you. So most of the time we think about bacteria, just because they've been easier

00:02:10.440 to study, but it also includes viruses, includes eukaryotic proteases, single cell, things like

00:02:15.640 yeast, for example. So really, it's the collection of all the microbes that are living in and on us,

00:02:20.840 and they're all invisible to the eye, but there's lots of them there.

00:02:25.160 Okay. And you said in the book that we are more microbial than human. What do you mean by that?

00:02:31.020 I don't mean to insult anyone, but so basically, there's a similar number of human cells in us

00:02:37.940 as there are bacteria. So they're about one to one. So there's many bacteria living in and on you

00:02:42.680 as there are human cells. And these bacteria encored about 100 times more genes than the homo sapien

00:02:48.580 genome. So you put two of those things together. I love to tell my students that they're more

00:02:52.540 microbial than human, just because there's so many of these microbes in and on us.

00:02:57.600 So give us like a number, like a rough estimate. Like what would that look like?

00:03:00.580 Yeah, it's about 100 trillion. What does that mean?

00:03:02.940 Well, let's talk graphics here. If you take a piece of feces the size of your fingertip,

00:03:07.840 I know it's a gross analogy, but hang in there. There are more microbes in that piece of feces 0.83

00:03:12.360 than there are humans living on the entire planet. So I jokingly say, think of the genocide,

00:03:17.500 you know, every time you flush the toilet kind of thing. There's a lot of them on it.

00:03:21.300 I mean, if you were able to clump all this into one mass, like how much would that weigh,

00:03:25.400 like how much of our body weigh would be microbes? 0.93

00:03:27.720 Yeah, it's about three or four pounds. So we kind of think the microbiome is sort of another organ.

00:03:32.140 It's about the size of your heart, for example, collectively, but they're dispersed. Most of them

00:03:36.000 are in the gut, the lower gut, but they're also all over many other parts of our body as well.

00:03:40.000 Yeah, because I think most people, when we think of the microbiome, they're thinking of,

00:03:42.740 we'll talk about this idea of gut health. But as you said, it's other places besides our guts.

00:03:48.500 Where else do we have a microbiome?

00:03:50.540 Right. I mean, the gut's the most obvious and basically the bacteria get more and more numerous

00:03:54.620 as you go down the gastrointestinal tract. And they're the most right near the very bottom in

00:03:59.480 what's called the large colon, the large intestine. And that's kind of really a paste of bacteria.

00:04:05.120 And there's 10 to the 8th, 10 to the 9th bacteria per gram of feces there. Phenomenal numbers.

00:04:09.920 Now, bacteria aren't in us. So generally the blood and inside our body is generally considered

00:04:16.340 sterile unless it's infected, but they're basically on us. So wherever our body is exposed to the

00:04:20.800 outside. So on your skin, for example, and like all living organisms, they like moisture. So there's

00:04:25.960 more microbes in your armpits and groin than there is, say, on your forearms. They're in your mouth and

00:04:31.280 the upper nasal tract. They're in the urinary tract, especially in women. And so basically wherever

00:04:36.200 your body is exposed to the outside, there's microbes that are there, kind of serving as this

00:04:40.920 filter between us and the outside world.

00:04:43.620 An interesting point you made in the book, and I had to think about this, and I was like, that makes

00:04:47.580 sense. We typically think of our gut as the inside of us, but technically it's the outside.

00:04:53.660 It's a tube running through us. That's right. It's really outside. It's just this one open tube that

00:04:58.140 goes from the mouth to the anus and there's lots of microbes in there. 0.74

00:05:01.280 Yeah. I had to think about that for a little bit. Oh yeah, it is. It is on the outside.

00:05:06.240 It's the outside going sort of like a hole through us.

00:05:09.440 It's a tube. That's right.

00:05:11.100 So, okay, the microbiome, it's bacteria, it's fungus, it's yeast, it can be viruses,

00:05:16.400 but not all of these microbes cause sickness or illness. So like, what's the difference between,

00:05:23.040 let's say, the bacteria that causes us to get the stomach flu compared to the bacteria that's just

00:05:28.700 always there and not doing anything to us, or maybe actually doing good stuff to us?

00:05:33.260 Yeah. I mean, the history of microbiology is focused on bacteria that cause disease,

00:05:36.940 called these infectious diseases. So that's, you know, salmonella causing typhoid fever,

00:05:42.560 that's listeria causing meningitis. But there's only about a hundred types of bacteria that can

00:05:47.420 actually cause disease in humans. Yet we have thousands and thousands of microbial species living

00:05:52.460 in and on us. And these are just basically normal residents under normal situations. They don't cause

00:05:57.840 any problems. And we're now realizing they're actually beneficial there. And so there's kind

00:06:02.560 of these two camps, those that cause disease and those that just sort of live on us and 1.00

00:06:06.240 really symbiotically and are actually beneficial for us. And so, yeah, we've historically focused

00:06:12.580 on the bad guys, but ironically, we're now starting to focus on the good guys and realize they actually

00:06:16.480 have a large role to play in our general health and well-being.

00:06:19.960 Okay. Okay. So how does this bacteria get on us? Like, where does it come from?

00:06:24.080 Well, there's bacteria everywhere. You can't see them, but they're everywhere. I mean, I

00:06:28.840 jokingly say the world is coated in a veneer of feces and microbes. The soil is full of microbes,

00:06:36.340 for example. And every food you eat, there's microbes in there until you cook them. They're

00:06:40.860 alive until you cook them. And every time you put your hand in your mouth, for example,

00:06:45.240 you're introducing microbes. I'm like, there's microbes all over your cell phone. They're all

00:06:48.620 over the toilet seat. They're all over the world. And it's a gross concept when you think about it,

00:06:53.020 but they're just there and this is normal and they're everywhere.

00:06:56.080 And then you also talk about throughout our lifespan, we get kind of hit with these microbes

00:07:00.860 in a healthy way. And like, it happens at the very beginning of life. Like once you're born,

00:07:05.740 that's when you get hit with a lot of these microbes that are potentially good for you.

00:07:11.020 Yes, that's right. I mean, I did write another book called Let Them Eat Dirt. We talk all about

00:07:14.700 how important this early life microbes is, and they really are important for development.

00:07:18.620 Generally, the fetus, so it's not born yet, is sterile, as far as we know. There are some

00:07:23.740 microbial signatures we haven't shown. There's live microbes in there. But the second you're born,

00:07:27.940 I mean, think about birth. It's a very messy business. But ironically, that first big gulp you

00:07:33.360 take, it's full of vaginal fluids, feces, all these other horrible things. But these are full of 0.52

00:07:38.520 microbes. And ironically, that's really good for the baby and really important. So as soon as you're

00:07:42.860 born, you get microbes. And anyone that's, you know, has a breastfeed kid, you know, the feces is

00:07:48.360 quite sweet smelling and stuff. But the second you introduce solid foods, it becomes very different

00:07:53.780 story because the microbes have now changed. And generally, once you're through adolescence,

00:07:59.100 you're pretty much entire adult life, your microbiome is pretty constant, doesn't really

00:08:02.580 change unless you do something drastic, like move or go into antibiotics or change diets.

00:08:07.440 And then as you age, post 65, the microbes do shift. And that seems to create some of the

00:08:14.100 problems associated with aging.

00:08:15.960 Let's talk about that one book you wrote, Let Them Eat Dirt. Because I remember when that came out,

00:08:19.780 I think someone wrote an article for our website, you know, and they cited that book. But the importance

00:08:24.320 of your kids playing in the dirt, getting out in nature, playing in mud, et cetera. Why is that so

00:08:30.300 important in childhood development?

00:08:33.080 It's really important. It's become more important. And I urge your listeners to go to YouTube

00:08:37.240 and look up Let Them Eat Dirt. We have a nice one hour documentary instead of, you don't have to

00:08:40.900 read the whole book. But what happens is these early life microbes, they basically help program

00:08:46.720 our body. We know that we're going to be born into a microbial world. So they play a major role

00:08:50.780 in developing our immune system. And this can determine whether you get asthma or not, for example.

00:08:55.760 They play a big role in obesity. They help our gut develop. They help our brain develop.

00:09:00.660 We know that animals don't have microbes. They don't develop normally. You need these microbes

00:09:04.580 a part of us. So when you think of how we lived as a species for millions of years, we were just

00:09:10.600 outside in lots of microbes everywhere. This is actually an important part of us. So in these days,

00:09:15.720 when a kid is born by a sterile cesarean section and then stays in a sterile apartment, doesn't get

00:09:21.460 outside and stuff, you're actually depriving the kid of the normal microbes that they need for the

00:09:26.040 normal development. And then we see the appearance of these diseases such as asthma and obesity and

00:09:30.920 things that are associated with an imbalanced microbiome early in life.

00:09:34.300 All right. And hopefully we can talk about the role the microbiome plays in things like obesity here

00:09:37.820 and the rest of our conversation. Because you dig into that, particularly how it can influence

00:09:42.740 obesity as we get older. This is what this book's about. The Microbiome Master Key is about

00:09:46.900 the microbiome past childhood, like when you're in your 30s, 40s, and then beyond.

00:09:53.100 So what does a healthy microbiome look like? And I imagine it's going to look different in different

00:09:59.520 parts of the body. Yeah, that's actually a really hard question to answer. For years, we struggled.

00:10:05.680 We're really good at saying what a non-healthy microbiome looks like. We could tell you pretty

00:10:09.740 quickly, oh, you're going to head towards inflammatory bowel disease or Parkinson's or whatever.

00:10:13.740 But we actually really struggle. What is a good microbiome? Basically, it's a very diverse

00:10:18.800 ecosystem. We all know that diversity in ecosystems are really important. You want lots of microbial

00:10:23.680 species there. Generally speaking, from the gut point of view, you want microbes that are good at

00:10:28.280 digesting fiber, because that is a very beneficial effect for us and as for the microbiome. And you

00:10:34.220 don't want microbes that are generally associated with inflammation. So these are microbes that,

00:10:39.440 I'll talk technical for a sec there, have something called lipopolysaccharide, which is a highly

00:10:42.960 inflammatory molecule. And it basically excites the host immune system and causes unwanted inflammation.

00:10:49.040 And that's a cornerstone to unbalanced microbiome. But there is no one perfect microbiome. You're

00:10:54.500 right. Not only each person has a unique set of microbes, so there's no one conserved microbe in all

00:10:59.680 people across the world. Different areas of the world have different microbiomes. Different parts of the

00:11:03.720 body have different microbiomes. So yeah, we struggle with saying, okay, this is the perfect, this is what you

00:11:09.100 should head for kind of thing. We know what's bad, but we have trouble saying what's good.

00:11:12.380 So what's bad? What does a bad one look like?

00:11:14.880 Yeah, well, the bad ones are basically the increase in these inflammatory microbes and decrease in the

00:11:19.400 short-chain fatty acid. I mean, the fiber fermenters, for example, that is generally bad. And that actually

00:11:25.380 generally also kicks in later in life when you shift towards a more detrimental type microbiome.

00:11:30.600 If you're eating a highly processed food diet, lots of white sugar, white flour, all the stuff that we love

00:11:36.660 to eat, that ironically is actually bad for your microbiome because it's already broken down. So you're

00:11:42.060 really starving the fiber digesting microbes down in your body. So that actually contributes to

00:11:47.120 problems like obesity and other type 2 diabetes and other issues.

00:11:51.320 So something I've seen, I'm sure people have seen this as well. They're like, well, I want to figure

00:11:55.840 out what my microbiome is like because I want to optimize. Everyone's about optimizing their health.

00:11:59.640 And so there's tests you can take where you actually, you poop and then you like swab your poop and 0.74

00:12:05.520 then you mail it. And then these companies can tell you, oh, well, here's, you have a healthy

00:12:09.560 microbiome. You have an unhealthy. Is there anything to that? Do these tests actually tell

00:12:13.580 you anything useful?

00:12:15.620 Really clinically? No, there's nothing clinical done yet. These companies say you should do it

00:12:20.180 every few weeks so we can tell you what you're doing and stuff. It gives you a general idea.

00:12:24.340 If you're a real nerd and want to know what's in you, it's really cool. If you're a microbiologist,

00:12:28.200 number of species names, it's really fun to put up in a post on your wall. But really it's not,

00:12:32.960 there's no clinical indications that you could say, okay, based on this, I should do that kind of thing.

00:12:37.580 So right now it's a general interest thing, but it's really not a medically proven test,

00:12:44.420 shall we say.

00:12:45.340 Okay. So it might be a great, like dirty Santa Christmas. 0.76

00:12:48.500 It's fun. It's just like, yeah, it's something fun.

00:12:49.960 It's really cool. 0.94

00:12:50.700 Hey dad, you want to know what's in your poop? Here we go. 0.96

00:12:53.160 Sure. You get your genome sequenced and you're 2% Neanderthal. You get your microbiome sequenced

00:12:57.740 and you've got some bacteroidetes and all these, all the cool things in there. And, but what do you do

00:13:02.040 with that? The problem is what you do with that. And right now we're lacking the information,

00:13:05.920 to say, based on this composition, you should do this. Yeah. So that's where we stand.

00:13:10.580 Are there moves to make these tests more useful? I mean, is that something companies and researchers

00:13:14.580 are trying to do?

00:13:15.920 They're thinking about it. And one thing we can say is that, you know, you can predict

00:13:20.260 many diseases based on the microbiome composition. Like you can tell if a person is obese just by

00:13:24.800 the microbiome. We have some work showing that we can predict whether someone has Parkinson's or

00:13:29.060 not based on the microbiome. But then knowing that, say, okay, what do I do to fix it? And that's

00:13:33.880 where the difficulty comes. The problem is standardizing it, making a universal test. And

00:13:38.880 so it's been difficult. So like I say, right now, there's no clinical test you can get done for the

00:13:44.360 microbiome.

00:13:45.540 So something people might've heard, and you talk about this in the book, and you mentioned this

00:13:49.660 earlier too, how we're raising kids these days where they're not exposed to microbes. We keep

00:13:55.020 everything very sterile and clean. It's having effects. How has modern life disrupted our

00:13:59.740 microbiomes?

00:14:02.000 Yeah. The easiest thought experiment is to think, how did we live, I don't know, 10,000,

00:14:06.200 100,000 years ago versus how we live now? I mean, historically, we were heavily in contact

00:14:11.580 with our environment at all times. It was a dirty environment. And we obviously got a lot of

00:14:15.760 microbes. We also died of infectious diseases very early. But then, you know, when we started to

00:14:22.160 realize that germs cause disease, society about 120 years ago went on a major hygiene campaign.

00:14:27.880 So let's clean the world up. Let's bring in hygiene. Let's bring in hand washing, hand sanitizer. 0.96

00:14:33.340 Antibiotics were invented. So we really cleaned the world up. And that had a spectacular effect

00:14:37.620 on decreasing infectious diseases. I mean, it used to be that, you know, most of your kids would die

00:14:42.400 in childhood. Now, very kids, very few kids die in developed countries of disease. But what we now

00:14:48.140 realize is that, oops, maybe we cleaned the world up too much. And the collateral

00:14:51.880 damage of getting rid of all microbes, we now realize that some of these are beneficial.

00:14:56.540 So antibiotic use is a major issue associated with microbiome disruption. Hygiene, as we've

00:15:02.060 talked about already, is a big thing. I mean, if you think how kids are raised these days,

00:15:06.240 when's the last time they got to roll in the dirt and get dirty and everything? Oh, no,

00:15:09.540 you'll get dirty. And COVID, of course, really set us back because we went back to more of a hygiene

00:15:14.520 type world. But we've been trying to push for a trend that we need a balance between if it's

00:15:20.440 potentially infectious, stay away. But if it's potentially not infectious, embrace the microbes.

00:15:25.560 And that's where the conflict lies. And pretty much all of modern life is around sanitation.

00:15:31.060 I mean, think how we design buildings. We, you know, get an airplane seat, we wipe it down with

00:15:35.920 an ethanol swab. You know, we wear masks all the time now. The world has really changed to be hygienic.

00:15:42.060 It's good for infectious disease. It's terrible for your microbiome.

00:15:44.500 And besides the hygiene aspect, as you mentioned earlier, diet. Our diet

00:15:49.220 has become more standardized, highly processed, and that's not good for the microbiome as well.

00:15:54.060 No, that is not good at all. I mean, you think how ancestors ate, they were chewing on nuts and

00:15:58.560 fiber and plant stuff and things. And we don't do that anymore. We have the nice processed foods.

00:16:04.280 And the problem is, like I said, they're already broken down. So let's see, we had to stick a celery,

00:16:09.040 for example, that's full of fiber. We don't have the enzymes to break down fiber, microbes do. So

00:16:14.440 the body relies on it going to the large intestine, where the microbes will chew away in the fiber. 0.93

00:16:19.400 And ironically, that's beneficial because the products of this fiber are anti-inflammatory.

00:16:23.660 They help the body grow and things. If you're eating white sugar and white flour and traditional

00:16:28.500 Western diet, it's already broken down. And really, there's nothing for the microbes to do.

00:16:32.780 So ironically, most of it gets absorbed in the upper small intestine and doesn't even make it down

00:16:37.540 to large intestine. So you're kind of starving your microbes there.

00:16:40.440 Yeah, I think the key is that our processed diets that we have, it's making our microbiome

00:16:44.940 in our gut particularly less diverse. And it's not just an individual issue. It could potentially

00:16:51.020 be a generational one. I think you said in the book that when people eat a low fiber,

00:16:56.980 highly processed diet, they lose certain gut bacteria, and then they pass on a less diverse 1.00

00:17:02.860 microbiome to their children. And you kind of make the argument that if we don't change

00:17:07.520 our diet, we could, for example, lose the bacteria that we need to digest fiber.

00:17:13.160 Yeah, the studies have shown that, you know, in my studies, if you deprive them of fiber for

00:17:17.240 about four generations, you can't go back. And many of us microbiologists are concerned that

00:17:22.340 we've evolved with all these microbes over the millennia, and suddenly we're taking them

00:17:26.440 out of our evolutionary equation. We're worried that, you know, a generation or two from now

00:17:31.100 will suddenly wake up and realize, oh no, we're missing these key microbes that basically

00:17:34.780 make us human. And what do we do about it? So there's even biobanking going on now trying

00:17:39.120 to preserve some of these and some of the uncontacted civilizations around the world and

00:17:44.100 trying to preserve it. But yes, there's a real concern that there's these missing microbes

00:17:48.380 that generation after generation, we're basically getting less and less diverse and we're losing 0.99

00:17:53.020 all the microbes that we need. And the worry is that we're going to put ourselves in a position

00:17:57.000 where suddenly we can't go back. And that's really scary.

00:17:59.060 All right. So modern life has disrupted microbiomes because we're too hygienic. You know, you're

00:18:03.660 not saying hygiene is not good, but like taking it to the extreme is not good. Antibiotics

00:18:08.300 are a great thing. It's saved a lot of lives, but if you just use it for anything, that's

00:18:12.620 not good because you kill the good bacteria or, and you even make the bad bacteria resistant

00:18:18.000 to the antibiotics, they become less useful. And then also just our diet is messing that up.

00:18:22.180 Well, so let's talk about some of the potential health consequences of not having a healthy

00:18:26.280 microbiome, of having an unhealthy one. Let's talk about the mecca of microbes is what you

00:18:31.160 call this area, the gut. What makes up our gut exactly?

00:18:35.960 Yeah. I mean, gut is obviously where you digest food. You chew it. It goes down to the stomach,

00:18:40.000 then onto the small bowel and the large bowel. And there's microbes at all these places and

00:18:45.380 they're heavily evolved. I mean, they see it as free food, right? Except for the light at the

00:18:49.340 end of the tunnel. From a microbial point of view, that's not good, but they're busy digesting

00:18:53.480 this food there. You're feeding them, you're watering them. And ironically, it's actually

00:18:57.460 really competitive for microbes to grow there. Like E. coli, most people heard of this bacteria

00:19:02.120 using a lab. It divides in lab in 20 minutes. In the gut, it divides every 24 hours because it's

00:19:07.720 in such competition with nutrients, with all the other bugs there. So really it's a paste of these

00:19:12.640 microbes there that are chewing on the food and stuff and they divide and replicate and you poop some

00:19:18.180 out and they continue to grow. And so you have this equilibrium of bugs in your gut. And this is

00:19:24.060 what can do many different things in terms of influencing our health and disease.

00:19:29.200 Yeah. The interesting thing that I learned from that is that there's more microbes in our large

00:19:34.200 intestine, in our colon, than there are in our stomach. I mean, there's some in our stomach,

00:19:37.960 not too many because it's too acidic in there.

00:19:39.540 Right. It's very acidic.

00:19:40.200 Then it increases a little bit as you get into the small intestine, but the colon, that's where it's...

00:19:43.400 That's where it's at.

00:19:44.480 That's where it's at.

00:19:45.560 They're also producing things like neurotransmitters. They got brain access. They

00:19:50.040 influence the brain, for example. They're chewing on these fibers, making a thing called short-chain

00:19:54.300 fatty acids, which are wonderful anti-inflammatory molecules that are key for health and basically

00:19:59.160 slow down aging. And they do a ton of different things. We haven't figured them all out yet.

00:20:04.060 There's just an amazing number of genes in there and they basically are doing a bunch of stuff.

00:20:08.280 And they obviously make these small molecules, we call them metabolites. And these can then

00:20:12.120 seep out of the gut to go into the body. And that's how you can have a bug in the gut

00:20:16.380 influencing somewhere else in the body, like the brain and the skin or something.

00:20:20.720 So what health conditions are connected with poor gut microbiome health that we know of?

00:20:26.540 Well, the joke in the field is what aren't. I mean, they all are. So, I mean, to give you an

00:20:31.480 example, there's what I think we use in the book, there's a list of the top 10 reasons why

00:20:36.480 a North American will die. And these are all the things you think about, like heart attacks and

00:20:40.760 strokes and cardiovascular disease and lung disease and things. When you take the top

00:20:45.020 10, only one of those is actually a microbial infection. That's pneumonia. I think that was

00:20:49.320 number eight. All these others are what we thought were traditional, just, you know, non-communicable

00:20:54.540 diseases. It turns out that nine of those 10 actually have microbial associations. And the only one that

00:21:01.460 doesn't really have microbial association that we know of yet is accidents. You could argue that

00:21:06.760 microbes influence behavior, which could cause aconus sort of thing. But all the others, like obesity,

00:21:12.360 like type 2 diabetes, like heart attacks, like strokes, like chronic lung diseases, called chronic

00:21:18.360 COPD, for example, kidney diseases, these all have microbes that are now being associated with this. And

00:21:24.700 bad microbes are actually being heavily associated with the disease. The slow part has been proving

00:21:29.900 this is actually causing the disease. Just because you have a disease, your microbes might be different,

00:21:34.360 doesn't mean it's causing it. But more and more cases, we now realize the microbes are actually

00:21:38.060 contributed to that disease in quite significant ways.

00:21:40.920 Well, and you have, you talk about diseases of the gut in particular, like IBS, irritable bowel syndrome,

00:21:45.860 ulcerative colitis. How does the microbiome affect those things?

00:21:50.880 Yeah, the gut diseases are pretty obvious to think about. Let's take inflammatory bowel diseases,

00:21:55.500 that's ulcerative colitis. And basically what happens is people with these diseases,

00:22:00.640 they have a genetic defect that basically they're not able to fight off or block the bacteria from

00:22:06.520 penetrating through the gut. So some of these inflammatory microbes get through and they then

00:22:11.000 trigger the inflammation, which then causes inflammatory bowel disease, which is basically

00:22:15.080 inflammation in the gut. So that's fairly straightforward that basically the gut bugs are

00:22:19.580 triggering inflammation, causing intestinal inflammation, causing these diseases. What's less

00:22:23.820 straightforward is say, for example, you know, Alzheimer's and dementia and Parkinson's,

00:22:27.680 for example, but gut microbes play a role in that. We know they play a major role in obesity.

00:22:33.280 This was established many years ago when people could take feces from a fat mouse and put in the

00:22:38.520 thin mouse and it got fat. And they could take a fat mouse, put the feces in the thin mouse,

00:22:43.160 it lost weight. And they could take feces from heavier set people, put it in mice, they would then

00:22:47.420 gain wheat. Unfortunately, we haven't narrowed it down and say, well, here's the perfect, you know,

00:22:51.960 lean bug, for example, have this bug and you'll be fine. And of course it's linked to diet. But,

00:22:56.220 you know, we now know that obesity, which is also a precursor to type 2 diabetes is heavily linked

00:23:01.260 with the gut microbiome composition. Yeah. With obesity, it seems like it's both

00:23:05.720 causation and correlation. So yeah, your microbes influence your weight, but your health habits

00:23:11.320 influence your microbes. And I thought the transplanting microbes from an obese mouse

00:23:16.640 into a non-obese mouse can actually cause weight gain was really interesting. There's also a case study

00:23:22.260 in humans where a woman who received a fecal transplant from her overweight daughter to

00:23:28.880 treat some bacteria infection she had, that woman later gained significant weight and became obese 1.00

00:23:35.000 herself despite she, and she never struggled with her weight before the transplant. So, so when there

00:23:40.680 is causation, is there a theory as to the mechanism? Like why does it certain micros make you more prone to

00:23:49.160 be obese or overweight? Yeah. The current theory is there's a, basically the obese microbes are

00:23:53.740 really, really good at harnessing energy out of any kind of food. So they generate a lot of energy

00:23:58.420 for not much input. And ironically, the healthy ones, Juno fiber stuff, they're actually kind of,

00:24:04.000 I was going to say crappy, but that's probably the wrong pun to use. They're not very good at

00:24:07.360 digesting the food. They don't generate as many calories. So these obese microbes just generate

00:24:12.220 calories like there's no tomorrow because they think you're starving or whatever. So they have to

00:24:15.880 generate a lot of calories. So that's the current thoughts, but it's not proven. And I think there's

00:24:21.060 still a lot of discussion in that area. Let's talk about another disease of the gut, colon cancer.

00:24:27.160 Yeah. This is an interesting one because like one of my guilty pleasures is I checked the Daily Mail,

00:24:31.780 the tabloid from the United Kingdom. And like one of their reoccurring things that always freaks me out

00:24:37.220 is young people getting colon cancer. And I'm like, oh my gosh, what's going on? Because you hear about

00:24:42.340 these stories of not only like 50, 60-year-olds getting colon cancer, but like 30-year-olds,

00:24:46.840 20-year-olds. And they have all these theories like it's your microbiome and your diet is causing it.

00:24:51.580 So what do we know about the role that the microbiome plays in colon cancer?

00:24:56.860 Yeah. I'm guessing that's what the princess had, for example. I mean, you're right. And this is

00:25:03.120 really scary because we are seeing a real increase in 35-year-olds and things. Historically,

00:25:08.080 it's been an older one. Just last week, I had the lovely pleasure because I'm getting older of going

00:25:12.640 through a colonoscopy. And I felt so sorry for my microbes because they must all be gone because you

00:25:18.000 have to clear them all out to get scope, for example. But so what we think is going on is because

00:25:23.540 for, again, our Western diet and our unhealthy microbes that they're, you know, sort of constantly

00:25:28.120 triggering inflammation in the gut, that's causing tissue damage. And then when tissue is repaired,

00:25:32.760 sometimes it's repaired incorrectly. You can get a mutation which can lead to cancer,

00:25:36.100 for example. And so we think that the diet, the unhealthy diet is associated with all these,

00:25:42.360 you know, disruptions in the gut that is then leading to colon cancer. There's also a micro

00:25:46.840 type of E. coli being associated with it, but it's not really fully proven yet, but it seems to be

00:25:51.200 associated with it too. But I mean, one moral of this discussion is that if you're young, don't rule

00:25:56.720 out getting screened for colon cancer. If you have a family history of polyps or colon cancer,

00:26:00.740 get the screen. I know it's gross, getting cleaned up for a day, but it could easily save your life.

00:26:07.120 And just because you're, I don't know, 35 no longer means you're immune to it, you could easily have

00:26:11.380 it. So get screened. The good thing is that colon cancer takes a long time to present. It's, you know,

00:26:17.180 about a decade or so. So for example, mine, I was clean. So they said, come back in five years.

00:26:21.460 So if you get the polyps, which are precursors to colon cancer, you can actually then prevent the

00:26:26.260 disease. And colon cancer is a horrible disease. So I know I'm preaching now, but this is something

00:26:31.460 that I think that we didn't really realize before. And it's really becoming prevalent among younger

00:26:35.500 people. And this can be a life-saving thing. We're going to take a quick break for your words

00:26:39.860 from our sponsors. And now back to the show. Okay. So we talked about the gut health, the role that

00:26:47.320 the microbiome plays in that. Let's talk about the role the microbiome plays in our immune system.

00:26:53.300 What's going on there? Everything. Okay. Yeah. Yeah. This has been, I think, a real cornerstone

00:27:00.540 of the whole microbiome field is what we realized is that even early in life, the microbes in the gut

00:27:06.760 are influencing how your immune system develops. And we had some studies that we did in our lab where

00:27:11.620 we showed that we could actually predict whether kids would get asthma or not based on their microbiome

00:27:16.660 at three months of age, because it would either push you towards an asthmatic allergic type reaction

00:27:21.500 or a non-asthmatic thing based on the microbiome. And what we now realize is the microbiome is heavily

00:27:27.120 programming the immune system to go the right way or the wrong way. And that's why kids that are born,

00:27:33.480 say, by C-section, they get the wrong microbes or antibiotics, the wrong microbes. They tend towards

00:27:38.480 asthma and allergies because they don't have the right microbes that are cuing their immune system up

00:27:42.320 correctly. And then all through life, the microbes are tweaking the immune system,

00:27:46.140 and it plays a really important role in this thing. And we talked a lot about fiber as being

00:27:52.340 anti-inflammatory. And I'll dive into this now. I mean, one of the key things about aging is this

00:27:58.700 chronic inflammation. Now, we know inflammation is good for fighting off infections and things,

00:28:03.500 but we now realize is as you get older, two things happen. You get more inflammatory microbes,

00:28:08.220 the bad ones, and your gut gets more permeable. And then these permeable bad microbes seep into the

00:28:13.740 body. They trigger this low-grade inflammation. And it's what we call inflammation. And as I was

00:28:18.700 writing the book, it was just scary because every aging process I looked at basically boiled down to

00:28:23.500 the same concept. Get older, microbes get bad, trigger inflammation, causes tissue damage,

00:28:27.740 which then causes, and you pretty much fill in every single one of the aging processes we see.

00:28:33.460 And studies have been done in mice, not humans yet, that you could take feces from an old mouse,

00:28:38.280 put it in a young mouse. It triggers inflammation, that mouse ages faster. And even better, if you

00:28:43.520 take feces from a young mouse, put it in an old mouse, it slows down the aging process, less

00:28:47.560 inflammation, and actually allows these mice to live longer. So maybe feces from a young person

00:28:52.980 really is the thought in youth. We don't know that yet, but it plays a major role in the whole aging

00:28:57.640 process.

00:28:59.100 So you mentioned gut permeability. I've heard that phrase thrown around a lot, and I kind of understand

00:29:04.260 what it is. Like, what is that gut permeability?

00:29:06.960 Yeah, we already talked about the gut being a tube, right? Well, it's not a polyethylene tube

00:29:11.760 that nothing can get through. It has to be permeable because you have to get the nutrients

00:29:15.120 from inside the gut into the body. So there's a bunch of cells that make up the wall of this tube,

00:29:20.360 and they're basically glued close together, and they have specific ways of transporting stuff

00:29:24.960 across that barrier. But in some cases, if you break the junctions between these cells,

00:29:29.600 you basically cause a leak in the pipe. And really, gut permeability is basically a leaky

00:29:34.360 porous type tube pipe, whatever you want to call it, in the gut. And so things beyond molecules can

00:29:40.980 seep through, and with these holes in the gut, now microbes can actually seep through true,

00:29:45.180 and then the body's immune system goes nuts when it sees these microbes because they shouldn't be

00:29:48.620 in the body, and that's when you trigger the inflammation. So leaky gut, permeable gut is just

00:29:53.440 as it says. It's basically your intestine is not as tight and as glued up as it should be.

00:29:57.780 Okay. So an unhealthy gut microbiome can cause inflammation because we have these microbiomes

00:30:03.020 that cause inflammation. Are there microbiomes that actually strengthen our immune system,

00:30:08.080 that make it stronger and respond better?

00:30:11.000 Yeah. There's a lot of studies starting to come out. There's some really neat studies on vaccine

00:30:14.600 responses that good microbiome gives you a better vaccine response than bad, for example. And we know

00:30:19.340 vaccine responses are going through the immune system. There's really nice studies showing out the

00:30:23.680 diet really does improve the immune system, and it's going through the microbiome.

00:30:27.780 So following a Mediterranean diet, for example, there's nice studies showing that actually does

00:30:32.060 strengthen the immune system and makes it stronger and allows you to fight off infections and all the

00:30:35.800 other things that the immune system does. So yeah, as to which bug's doing what, I think the details are

00:30:41.940 still being filled in. We don't have all the answers yet, but there's no doubt this plays a big role

00:30:45.900 in the immune system.

00:30:47.040 Related to the immune system are autoimmune diseases, where your immune system goes on overdrive and

00:30:52.720 starts attacking healthy parts of your body, like a common one, rheumatoid arthritis or multiple

00:30:59.320 sclerosis.

00:30:59.940 MS.

00:31:00.540 Yeah, MS. Is there a connection between the microbiome and autoimmune diseases?

00:31:04.440 There is. People with those diseases have different microbes, morpul inflammatory, as we discussed.

00:31:09.220 So there is a correlation, but I can't tell you mechanistically how do they cause MS or rheumatoid

00:31:16.960 arthritis. I mean, we know certain microbes associated with it. There's very good predictions

00:31:20.580 involved. Presumably, these microbes are triggering inflammation and stuff that causes the body to

00:31:25.840 react with itself and cause these autoimmune diseases. So there's correlation, but not causation yet.

00:31:30.860 Not causation yet. Okay, let's talk about brain health. So you mentioned some diseases that are

00:31:34.640 connected to the microbiome. Alzheimer's is one you mentioned earlier, but even depression. There's

00:31:40.220 like a connection or correlation between the microbiome and depression. Talk to us about that.

00:31:44.020 I think that was interesting.

00:31:45.960 Yeah. I mean, I think, you know, one of the most exciting areas in this field is what we call the

00:31:49.240 gut-brain axis. How do the microbes influence the brain? Now we know the brain influences the gut.

00:31:54.240 There's this nerve that goes down called the vagus nerve that influences gut motility and things.

00:31:58.720 But now we realize that microbes are pulling out the other end of this nerve and they're sending

00:32:02.240 signals up to the brain. And just to give you some examples of how this all works is if you take an

00:32:08.020 anxious, stressed, or depressed mouse or rat, do a fecal transfer into a normal mouse or rat,

00:32:14.160 those normal mouse or rat now become anxious, stressed, or depressed just by transferring the

00:32:18.640 microbes. There are studies in the UK that have done big studies. Look, people use antibiotics.

00:32:23.840 They are much more susceptible to anxiety, depression type thing. So there's these microbial links there.

00:32:29.880 And then the big ones in terms of mental aging diseases, of course, are Alzheimer's and to a

00:32:35.000 lesser extent Parkinson's disease. These are two awful diseases. Alzheimer's is basically the type

00:32:40.560 of dementia. But microbes seem to be involved in that probably because triggering the inflammation,

00:32:46.440 triggering the tissue damage, triggering the brain damage. And as we talk about in the book,

00:32:51.100 that if you eat a healthy diet, something called the MIND diet, which is basically a modified

00:32:55.160 Mediterranean diet, you can drop your incidence of Alzheimer's disease by over 50%, which is just

00:33:01.560 stunning in that sense. And work we've done in our own lab is that working on Parkinson's disease,

00:33:07.800 that's a disease that causes tremors and you're sort of stooped over and stuff. It's about 1% of

00:33:12.740 the population. And we showed that basically if people followed the MIND diet, again, which is the

00:33:19.260 Mediterranean diet, basically, that it delayed the onset of Parkinson's in women by 17 years and by

00:33:25.120 men by over a decade. And given the Parkinson's doesn't actually kick in until age 65 plus normally,

00:33:31.720 you're going to die of something else first. And we know this has got microbe related because we've

00:33:36.700 done all the studies showing that gut microbes and Parkinson's are different. And it all got started

00:33:41.260 by cutting the nerve that hooks the gut to the brain, the vagus nerve. When you cut that,

00:33:45.020 you have less levels of Parkinson's. And so the way we think Parkinson's actually works now is it

00:33:50.860 starts in the gut. And the biggest indication of getting Parkinson's is constipation 30 years before

00:33:56.060 you get it. And the second biggest risk factor is eating red meat. So these are both gut things,

00:34:01.020 right? And so we think basically you have a bad gut microbiome and it causes misfolding this protein in

00:34:07.780 the gut, something called alpha-synuclein. And that goes up the vagus nerve into the brain,

00:34:12.420 part of the brain that makes this dopamine, which suppresses tremors and things. And it

00:34:17.160 destroys those cells. And then you start to see that the brain disease and depression.

00:34:21.940 So bottom line is prevent these diseases, eat a healthy diet. And I think that really bodes well

00:34:27.120 for good brain health. There's all sorts of research. Can we find a magic bug that decreases

00:34:32.180 depression and stuff? Psychobiotic, you call these things. We don't have these yet. There's some hints of

00:34:37.880 probiotics and things, but we don't have good data yet. But that's where this is all going. Can

00:34:42.300 we actually influence the brain via gut microbes? Yeah. One thing I've seen, and this is all

00:34:46.880 speculative, of course, but with depression, one thing I've seen thrown out there for, oh,

00:34:51.500 here's how you can help it, is eat resistant starch, like a food with resistant starch. And then

00:34:57.840 I guess the gut microbiome breaks that down into the short chain fatty acid, particularly like

00:35:03.560 butyrate, I think that's how you putyrate. Yeah. Like the more butyrate you have, somehow that's

00:35:07.740 supposed to help stave off depression. I don't know. Yeah. Good job, Brett. You turned into a

00:35:11.320 scientist. Yeah, I'm a scientist now. Yeah, I'm an expert. Yeah. So fiber basically is broken down

00:35:17.220 into what we call short chain fatty acids, and butyrate is the big one among these things. The

00:35:22.580 joke is if you're at a microbiome concert, you want to know, meeting, you want to know what the

00:35:26.580 Wi-Fi password was, it's probably butyrate, because butyrate seems to be involved in absolute

00:35:29.780 everything. And butyrate is an anti-inflammatory molecule that decreases inflammation. And so the idea

00:35:35.820 is that if you're depressed, you know, eating a better diet, you decrease the inflammation,

00:35:39.920 hopefully decreased, you know, symptoms associated with it. Ironically, it all gets boring. It all

00:35:45.020 boils down mainly to diet and exercise. It's just boring. I want the magic pill, right?

00:35:49.400 Right.

00:35:49.820 Unfortunately, the magic pill is eat right, get some exercise, don't stress, get a good night's sleep,

00:35:55.060 and enjoy life, really. But that doesn't come in a pill form, so.

00:35:59.040 Yeah. At the end of this conversation, we'll talk about what you can do for your microbiome health,

00:36:01.580 and it'll be like, it's basically a recap of what you've been saying throughout. Eat a good diet,

00:36:05.880 but we'll get into more specifics. You have some other interesting things there.

00:36:08.200 Yeah. Let's talk about the microbiome in our mouth. So that's the opening of that tube

00:36:12.480 that goes through our body. How does our microbiome in our mouth affect things like

00:36:17.840 cavities or even bad breath?

00:36:20.280 Well, it drives both those things. I mean, ironically, the microbiome in the mouth is the

00:36:24.200 earliest studied microbiome. There was a guy named Anthony van Leeuwenhoek in the late 1600s who

00:36:29.200 invented the microscope, and he wanted to look at things. He looked at cool things like his sperm,

00:36:33.740 but the other things he did is he swabbed out his mouth, and he made this most profound statement.

00:36:38.480 There's more animalcules, which we now know are bacteria, in his mouth than there are people

00:36:43.580 living in the Netherlands, which is where he's living at the time. Of course, no one believed

00:36:47.360 this crazy guy seeing what you can have living things in, but ironically, that was, of course,

00:36:51.260 the mouth microbiome. And your mouth is full of microbes. It's a fun experiment. Swab it out,

00:36:56.500 stain it. You'll see all these microbes in there. And they do all sorts of things. Yes,

00:37:00.740 some cause teeth cavities, so they chew away at the enamel in the teeth and then bury into it,

00:37:05.400 and that causes teeth cavities. One of the bigger problems is they cause inflammation of the gums

00:37:10.400 around the teeth. Whenever you go to the dentist, they floss your teeth. Why are they telling you to

00:37:14.140 floss your teeth, brush your teeth? Well, that's because it's for good gum health. And if you have

00:37:18.280 crappy gum health, then it's inflamed. There's microbes living there. And also, that allows the

00:37:24.160 inflammatory microbes to seep into your body, and they get through these inflamed guts and then cause

00:37:28.240 the problems associated with the inflammation. And just to give you interesting examples that,

00:37:34.300 you know, if you brush your teeth three times a day, you basically drop your Alzheimer's rates

00:37:38.080 by about 50%. You say, well, what does good oral health have to do with Alzheimer's? And of course,

00:37:43.860 the answer lies in the microbes that if you don't brush your teeth, you have poor gum health.

00:37:47.980 Microbes seep through. They trigger inflammation, causes tissue damage, which then seems to be

00:37:52.000 associated with Alzheimer's disease. Yeah. Whenever I go to the dentist, there's next to the chair,

00:37:56.380 they have this poster, and it's got a body on there. And it points to all these things. If you

00:38:01.620 don't floss, here's how it's going to affect, like one of them is heart disease. Like if you don't

00:38:06.660 floss and you get, you're going to have periodontal disease and you're going to have a heart attack.

00:38:11.740 And I'm like, okay, I need to floss. I need to start flossing again. And then my motivation lasts

00:38:16.880 for like three weeks. So yeah, what role does the mouth microbiome play in heart disease? Is it the

00:38:23.900 same for things, just inflammation? Same as we were discussing, these inflammatory type

00:38:29.060 things that inflation is hard on the heart. And then it could lead to these heart things because

00:38:33.300 you allow the microbes to seep into the body. Because just like the gastrointestinal tract,

00:38:37.700 the mouth is generally pretty impermeable for allowing bugs into the body, unless you have poor

00:38:41.840 gum health. And then that's a ticket for all these oral microbes to then seep into the body and trigger 0.99

00:38:47.200 these problems. So yeah, it's an interesting way of guilting you into flossing your teeth and stuff,

00:38:51.620 but it's actually good for you. And that's why it's a good gum health.

00:38:55.680 One thing you mentioned in the book as kind of an aside, but inspired me to go try this out.

00:39:01.000 Probiotic gum for oral health. Is there anything to that?

00:39:04.540 There's some. I mean, every time you go and get your teeth cleaned, especially if you do what's

00:39:08.840 called an acid wash, they just destroy all the microbes in and on your teeth. The reason you're

00:39:13.000 getting teeth cleaned, all that plaque, all that white stuff they chip off, they're called

00:39:17.000 extracellular polysaccharides. They're carbohydrates, they're sugars basically that these microbes

00:39:20.920 produce and they build this basically impermeable wall around them. And that's when they're chipping

00:39:26.820 off the plaque. But every time you get your teeth cleaned, they strip it down to nothing.

00:39:30.940 And it's really interesting as to which bug adheres first. That sets up the hierarchy of

00:39:35.300 who's going to then come next. And depending who adheres first, that dictates who's come second

00:39:39.820 and third and stuff. So this probiotic gum seems to actually help establish getting good microbes

00:39:45.320 down first. So they set up the rules. Okay, we're going to be a good call in here. We're going

00:39:49.120 to build these microbial skyscrapers based on this as opposed to based on, say, a pathogen.

00:39:54.600 So there's some data on the probiotic gum, much like all probiotics. It's not that great

00:39:58.800 data yet, but there's some there. And so, yeah, how did it taste?

00:40:02.860 It was okay. I mean, it tasted like gum. It was kind of, it was a little chalky.

00:40:06.400 Yeah. Eating microbes.

00:40:08.900 Yeah, eating microbes.

00:40:10.360 We'll talk more about probiotics here because I think that's interesting. But let's talk about

00:40:13.480 one more thing, the microbiome on our skin. I've been seeing more about this in advertisements

00:40:19.600 with skincare products. They talk about, oh, this is good for your microbiome on your skin.

00:40:24.660 So what does the microbiome on our skin do?

00:40:28.220 Yeah, well, as I said, you have microbes coated all your skin and wet areas, there's more microbes.

00:40:33.300 But each place on your skin has a certain microbial collection and your right hand is going to be very

00:40:37.420 different than your left hand because they do different things and they touch different things and

00:40:41.300 that's normal. But one of the biggest things they do is they fight off, they basically hog all the

00:40:46.980 sites that a pathogen could buy to. So skin effects and stuff are less than people with

00:40:51.500 healthy microbiomes. They also seem to be helping with skin health. And you know that as a teenager,

00:40:57.460 when you get pimples, for example, that's because the bacterium is chewing on the oil your face makes

00:41:01.600 as a teenager and that then generates some acne and pimples, for example. There's interesting stuff

00:41:07.240 coming out on probiotics and skin health. It's not perfect, but I think there's some

00:41:11.180 interesting data coming out that seems to enhance it. And not just skin microbes, gut microbes.

00:41:15.780 There's lots of studies coming out showing that if you have healthy gut microbes, it actually

00:41:18.940 improves your skin health and helps decrease radiation damage when you get sunburned, for

00:41:23.720 example. Both the skin and the gut microbes seem to decrease the skin damage that ultimately

00:41:29.060 results in wrinkles and your skin collapsing as you get older and all the skin things associated

00:41:34.240 with aging. So yeah, the cosmetic industry is certainly capitalizing on this. They kind of take

00:41:39.500 it too far, in my opinion, sometimes. But there is some interesting stuff coming out that you can

00:41:43.220 actually put microbes in skin creams and then may enhance your skin health type thing.

00:41:49.120 Yeah. I mean, one thing that you speculated on is that maybe you could bank your microbiome,

00:41:54.440 skin microbiome, when you're like 20, so that when you're in your 60s, you can like apply it on your

00:41:59.980 face to maintain your youthful looks.

00:42:03.540 Sheer speculation, but we know that the microbes on your skin at 60 are different than those at 20.

00:42:08.820 And are they doing this? I don't know. And they've done experiments in mice and other things. And

00:42:14.080 even in people where they take older people, microbes put them on younger people, seems to

00:42:18.440 cause poor skin health and vice versa kind of thing. So yeah, I mean, maybe there's hope. 1.00

00:42:25.340 We all want to look good forever, but maybe this could help.

00:42:29.320 I thought it was interesting too. Just kind of my mind was blown when I heard about this.

00:42:32.600 Just speaking of our microbiome on our skin, because it's the one that's

00:42:36.180 most exposed to our environment. But you talk about how every one of us has our own unique

00:42:42.500 microbiome. We all have a different one. And you could go into like a hotel room and your microbiome

00:42:48.920 will just like populate that entire hotel room. You can tell like, okay, this family was in this

00:42:54.920 hotel room just by measuring the microbiome, like on the TV remote control.

00:42:58.900 Yep. You can.

00:43:00.660 Yeah. Then another family comes in and like that microbiome just colonizes and takes over.

00:43:05.160 Yeah. I mean, changing the sheets isn't enough. It's just the way it is. We slough skin cells.

00:43:09.460 We also slough microbes and you can easily see the microbial signatures of people. And as you say,

00:43:14.800 they change over as the people change over. There's nothing wrong with it. It's just biology in

00:43:19.140 action. It's what it is. And like, it's not associated with getting infected with someone because

00:43:23.440 the people before you had some microbe, it's just the way it is. It's just biology.

00:43:27.460 Okay. Let's talk about nurturing a healthy microbiome because I'm sure this is the thing

00:43:31.560 that people want to, this is what they're listening for. Like, what can I do to have a

00:43:34.260 healthy microbiome? And we've mentioned some things already, but the diet sounds like just

00:43:38.100 eat a well-balanced diet, particularly a lot of fiber because your gut microbiome needs that.

00:43:42.800 Is that pretty much it?

00:43:44.100 Yeah. So diet is first and foremost, the biggest thing that affects at least especially your gut

00:43:48.420 microbiome. And the more plant fiber you eat, the better off you're going to be. You want to

00:43:53.000 decrease red meat. You can probably have it once in a while, but you should not be eating red meat

00:43:57.220 regularly. That's not good for the microbiome. And of course, stay away from processed foods,

00:44:02.520 including things like white sugar and white flour. Always go for the whole grains.

00:44:06.960 And sort of the saying is, you know, walk around the outside of the grocery store and stay away from

00:44:11.300 the middle because in the middle is all the processed foods. There's nothing good for microbes in 0.88

00:44:15.080 there whatsoever. And you want to stick to the, you know, the produce counters and stuff like that.

00:44:19.800 So diet is first and foremost, the biggest one.

00:44:23.020 What about fermented foods? Because that's food that has bacteria in it. Does that have a benefit?

00:44:28.140 It does. Kimchi. During COVID, I worked on becoming a sourdough bread maker kind of thing

00:44:35.200 because everyone did. And, you know, I thought, well, sourdough bread, it's cooked, right? So is it

00:44:40.540 probiotic or not? And it turns out that it's actually good for you because of all the microbial

00:44:44.980 products that are in the cooked bread and they've broken down the things in a beneficial way.

00:44:48.860 But yeah, all fermented foods are, generally speaking, they're quite good for you and definitely

00:44:53.720 embrace those.

00:44:54.860 Yeah. I eat, part of my routine is I have, with breakfast, I have like a scoop of kimchi.

00:45:00.000 Excellent. Or sauerkraut or anything like that.

00:45:02.120 Sauerkraut. I love sauerkraut. And then I eat yogurt. I like, you know, Greek yogurt is another

00:45:06.900 thing I eat. What about mentioning probiotics? Because we typically think, okay, eat yogurt because

00:45:13.020 it has probiotics. Eat kimchi has probiotics. Probiotic supplements, you're seeing advertisements 0.98

00:45:17.960 for this all the time. Do probiotics actually do anything for us, like the supplement types?

00:45:24.320 Yeah, this is a hard one. Bottom line is a probiotic, basically, it's not going to hurt you.

00:45:30.960 But the real argument is it's good for you. And there are some probiotics that we've proven

00:45:35.100 in clinical trials for some clinical indications. There are some probiotics that can be used for,

00:45:40.800 say, antibiotic-associated diarrhea. Take antibiotic diarrhea. Some work there.

00:45:45.960 There is yeast, means it's associated with decreasing clostridium difficile infections.

00:45:50.300 The analogy I like to use is that you need a new pair of runners. You walk into a running

00:45:53.940 shoe store and there's this wall full of runners. There's joggers and hikers and basketball shoes

00:45:58.420 and tennis shoes and whatever. You don't just grab the cheapest pair and walk out.

00:46:01.780 And say with probiotics, you just Google the word probiotic chart and there's one for both

00:46:06.880 U.S. and one for Canada. And there it lifts what all the probiotics are and what is the clinical

00:46:12.340 evidence they will do something for a particular disease. Now, there's no probiotics that have been

00:46:17.880 proven to basically make you feel better because that's clinically a really tough endpoint and

00:46:23.080 no company's ever going to want to do that. So there's some that work, but really they're quite

00:46:28.400 few and the clinical evidence is very poor. They're not like night and day like an antibiotic

00:46:32.760 treatment. It's just night and day for curing an infection. But all that said is I'm really

00:46:37.940 hopeful for the future we'll get into these worlds where we're adding eight, ten microbes and it'll

00:46:43.280 have a defined biochemical outcome. They'll be taking that as a drug really. It's gone through

00:46:47.340 the clinical trials and there's several that are now coming down the pipes of exactly this where

00:46:51.840 you get a prescription from a doctor for this mix of microbes to actually do this. And I call that

00:46:57.520 probiotics 2.0 or next-gen probiotics. I think that's where the real excitement's coming.

00:47:01.540 Okay. So it sounds like take one if you want. It's probably not going to do much for you.

00:47:06.960 It's not going to hurt you. But it sounds like you're probably going to get more bang for your

00:47:10.180 buck focusing on the prebiotics, like eating the fiber food that gives your microbiome stuff to

00:47:17.080 munch on.

00:47:17.820 Yeah. I mean, there's three classifications. There's probiotics, which are basically live microbes.

00:47:23.420 And they tell you how many microbes are alive when you take this thing. The problem is that they

00:47:28.400 pretty much die as soon as they go inside you. I mean, for example, lactobacillus is a microbe from

00:47:33.120 the vagina, which is a very different world than the gut. And you swallow this lactobacillus,

00:47:37.960 vagina's got air and it's acidic pH. The gut has no air and it's a basic pH. So these things just die. 1.00

00:47:43.320 So that's why you have to take them every day. It's a great marketing point of view because you

00:47:46.880 have to take this every day. But you're just basically taking a microbial goo kind of thing.

00:47:50.700 So, you know, the new mixtures will be microbes from the gut and for the gut that will actually

00:47:55.740 then take that and actually set up a colony and live in the gut. And it's not such a great marketing

00:48:02.560 design because ideally if it works, you should only have to take it and then you want to take

00:48:06.740 it again. But that's where we're heading with these things.

00:48:10.140 Gotcha. What about any activities? Like you talked about let them eat dirt. You want your kids out

00:48:15.440 there playing in the mud. As an adult, should we be doing the same thing? Getting out in nature

00:48:19.520 and possibly making mud pies? Absolutely. Yeah. Especially if you can insult your microbes,

00:48:24.420 like you'd have to take antibiotics for an infection. How do you fix them? There's no

00:48:28.000 mix of microbes you can actually just take right now to make your microbes good. The best way is

00:48:32.580 eat healthy and get outside and, you know, embrace microbes. Let your dog look you in the face,

00:48:39.240 for example, all these kinds of things that generate microbes. I mean, you know, you take elder care

00:48:44.660 homes, you think how we treat people in there. I mean, I personally think there should be dogs and little

00:48:48.900 kids running through these places and let them defecate all over the place. And that's how you're

00:48:52.800 going to get these young microbes into the elderly, as opposed to the crustless white sandwiches and

00:48:57.600 don't let anyone in kind of thing. I mean, that's a terrible way for a microbe point of view to live. 0.99

00:49:01.840 So embrace your microbes and then doing that, that'll actually improve your health.

00:49:05.580 And then also don't be so sanitary inside your house.

00:49:09.120 Right.

00:49:09.580 Be sanitary, but don't take it to an extreme.

00:49:11.720 Yeah. If you've got mold growing and stuff, that's probably not a good idea. But don't worry if a hunk of food

00:49:16.600 falls on the floor, it's just fine. It's not, you know, unless it lands on a pile of bolts or

00:49:20.400 something, it's fine. So yeah, it's this balance of hygiene and stuff. I mean, other, other proactive

00:49:25.080 things. So we talked about diet. I mean, exercise is really important. Exercise really decreases the

00:49:30.540 inflammatory microbes and pushes your microbes to a more anti-inflammatory type thing. And all the

00:49:35.620 studies show that we know exercise is good for us. It's actually really good for your microbes too,

00:49:39.900 which is part of the reason why exercise is good for us. So you want the exercise and you don't have to be a

00:49:45.000 marathon runner, but just, you know, even daily walking of things has a massive effect on the

00:49:49.380 microbes. You want to get a good night's sleep, diet has a big effect on microbes that allow you

00:49:54.440 to sleep better and type things. So there's good sleep. The point we have the most problem with in

00:49:59.160 our society, I think, is stress. And we live in a very stressful world. I mean, even if I sit there

00:50:04.480 all day, my watch says, you have had a stressful day, you should relax. Now it drives me nuts. But,

00:50:08.300 you know, stress has a terrible effect on your microbes. Again, driving them towards the

00:50:13.500 pro-inflammatory type thing and basically making them bad microbes again. And the final thing is

00:50:19.480 community. And this is one thing we tend not to embrace so much is that, you know, community is

00:50:24.880 really important. And that's probably because it's microbial swapping. There's a cool study that could

00:50:29.020 tell who played cards with who based on their microbial composition. So you're swapping microbes with

00:50:34.260 your friends kind of thing. So I jokingly say maybe dating apps should have a microbiome screen so

00:50:39.780 that you can, you know, who are you dating and what are your microbes? I don't know yet.

00:50:44.760 Okay. So to have a healthy microbiome, you want to avoid processed foods, eat more fiber,

00:50:50.040 maybe some fermented foods, exercise that decreases inflammatory microbes, de-stress. Don't be overly

00:50:57.700 scrupulous about hygiene. You recommend not using antibacterial soap unless absolutely necessary.

00:51:04.260 Because just plain old soap and water works is fine in most cases. Sleep is also another component

00:51:09.720 to a healthy microbiome. There's a two-way relationship there. Good sleep supports a

00:51:14.420 healthy, diverse microbiome while disrupted sleep can start just kind of throw things out of whack

00:51:19.880 in your gut. And then in turn, the gut microbiome can help regulate sleep-related hormones like

00:51:26.360 melatonin, GABA, serotonin. So, you know, that means a healthier microbiome can lead to better sleep

00:51:32.540 or support better sleep. And then hang out with people. Diversify your microbiome by getting in

00:51:37.260 contact with other people's microbiomes. And then another thing I think is just be judicious with

00:51:43.760 antibiotic use. So if your doctor prescribes you antibiotics, you can ask, do I really need to take

00:51:49.360 antibiotics? Yeah. I mean, historically, we sort of say, well, antibiotics can't hurt. Take them anyway.

00:51:54.160 I mean, kids with otitis, medias with ear infections, they get prescribed antibiotics all the time.

00:51:58.420 Well, that's often a viral infection and the antibiotic's not going to do anything.

00:52:02.780 And there's two reasons why you want to avoid antibiotics. One is the increase in the antimicrobial

00:52:07.280 resistance, which is a huge issue. Bugs get resistant to it. But secondly, now it has a really

00:52:12.960 carpet bombs your microbiome. So if you have a life-threatening disease that antibiotics are

00:52:17.980 needed, absolutely take it. But if it's something that, ah, might not work or whatever, I think there's

00:52:23.120 still the lack of realization out there that they do have these secondary effects. And people take

00:52:28.520 antibiotics are much more prone to be obese, have high levels of asthma, have mental diseases. There's

00:52:33.580 all these studies coming out now showing that long-term multiple antibiotic use is really just

00:52:37.920 not good for you because it impacts your microbiome. Well, Brett, this has been a great

00:52:41.900 conversation. I think we understand the microbiome now. Where can people go to learn more about the

00:52:45.600 book and your work? Well, it's called The Microbiome Master Key. Harness your microbes to unlock

00:52:50.620 whole body health, lifetime vitality. It's available on Amazon, etc. You can Google me. We have a lab

00:52:57.200 webpage and thinking about our work. And also, like I said, if you have kids, look up Let Them Be Dirt or

00:53:02.740 watch the YouTube video of the documentary on that thing. I guess I just urge people to think about how

00:53:08.100 we live and to embrace the microbes as part of our living. And when you scroll through the news and

00:53:13.440 stuff, it's all about exercise and things. But why is that good for us? And we now realize that a

00:53:18.460 major component of that is the microbes. And the good thing is you can change your microbes. You

00:53:22.360 can't change your genes, but you can change your microbes. So if we can change our microbes,

00:53:26.140 there's actually hope for fixing things and basically pushing more towards the health and

00:53:29.900 vital type aging process. So that's the idea of all this.

00:53:33.940 Fantastic. Well, Brett Finlay, thanks for your time. It's been a pleasure.

00:53:36.180 Thanks a lot, Brett.

00:53:37.040 My guest here is Dr. Brett Finlay. He's the co-author of the book, The Microbiome Master Key. It's

00:53:42.220 available on Amazon.com and bookstores everywhere. Check out our show notes at

00:53:45.080 awim.is slash microbiome, where you can find links to resources when we delve deeper into this topic.

00:53:57.160 Well, that wraps up another edition of the AWIM podcast. Make sure to check out our website at

00:54:00.980 artofmanly.com, where you can find our podcast archives. And make sure to check out our new

00:54:04.420 newsletter. It's called Dying Breed. You can sign up at dyingbreed.net. It's a great way to support the

00:54:08.820 show directly. As always, thank you for the continued support. Until next time, it's Brett McKay.

00:54:12.780 Remind us how to listen to the AWIM podcast, but put what you've heard into action.

The Art of Manliness - July 15, 2025

The Microbiome Master Key — How 100 Trillion Bacteria Influence Your Weight, Mood, and All-Around Health

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