Latest / Daniel and Kelly’s Extraordinary Universe / Do microbes help or hurt you? (featuring Katrine Whiteson)

Transcript

Do microbes help or hurt you? (featuring Katrine Whiteson) · Daniel and Kelly’s Extraordinary Universe

0:05
Speaker 1: Nobody likes getting colonized by microbial invaders, Those little guys
0:10
Speaker 1: swimming around inside you, messing up your body's normal function,
0:13
Speaker 1: hijacking yourselves to make more themselves, meanwhile giving you headaches
0:17
Speaker 1: or sniffles or stomach pains or even worse. No, we
0:20
Speaker 1: want them out. We take medicine to kill them, or
0:23
Speaker 1: we wait for our immune system to hunt them down
0:25
Speaker 1: and root them out, leaving us with pure, unpolluted human bits.
0:30
Speaker 2: Right.
0:30
Speaker 1: Not really, Actually, the truth about our relationship with microbes
0:34
Speaker 1: is much more complex. They not only fight on our side.
0:38
Speaker 1: Sometimes most of the time we can't even tell who
0:41
Speaker 1: is on which side, or if there are even sides.
0:44
Speaker 1: Maybe it's more like a big microbial economy than a
0:46
Speaker 1: black and white battle. Today in the podcast, we're gonna
0:49
Speaker 1: dig into the life of microbes and the role they
0:51
Speaker 1: play in keeping us healthy and sick. Do they help us,
0:54
Speaker 1: do they hurt us? Or is the answer? As always,
0:57
Speaker 1: it depends a word to today's parents. Today's episode is
1:01
Speaker 1: getting a little gooey. We can't talk about microbes without
1:04
Speaker 1: talking about pooh. It's always a conversational risk when talking
1:07
Speaker 1: to biologists, so keep that in mind if you're playing
1:10
Speaker 1: this episode with your little ones. I vote let them listen.
1:13
Speaker 1: There's pooer in knowledge. See what I did there? Either way,
1:17
Speaker 1: Welcome to Daniel and Kelly's extraordinary microbial universe.
1:35
Speaker 3: Hello. I'm kellyleener Smith. I study parasites in space, and
1:39
Speaker 3: today we are talking about one of my favorite topics
1:42
Speaker 3: as a biologist, which is to say, microbes and poop.
1:46
Speaker 1: Hi. I'm Daniel. I'm a particle physicist, and I have
1:49
Speaker 1: poop in my freezer.
1:50
Speaker 3: Oh oh, that's a little too much, all right? So
1:53
Speaker 3: what is the most unpleasant microbe related thing that's ever
1:57
Speaker 3: happened to you?
2:00
Speaker 1: You want to hear about every time I had diarrhea?
2:03
Speaker 3: Maybe the one worst time is what I was thinking.
2:06
Speaker 1: I guess maybe not to hear about that.
2:08
Speaker 3: Never mind, I'm backing off. For me, it was an
2:10
Speaker 3: infection that was a healing and that was unpleasant. We
2:13
Speaker 3: should go in a different direction. What else should I ask?
2:16
Speaker 3: Here's my question for you? What is your favorite thing
2:19
Speaker 3: to consume that increases the diversity of your microbiome however
2:24
Speaker 3: temporarily well.
2:25
Speaker 1: As you'll hear in our conversation with Katrina in a minute,
2:28
Speaker 1: we are big fans of beans, in the whites and household.
2:30
Speaker 1: And so we're even members of the Rancho Gordo Bean Club,
2:34
Speaker 1: which means we have mailed to us every few weeks
2:37
Speaker 1: a box of heirloom beans, and so we have all
2:40
Speaker 1: sorts of crazy beans and basically we have beans at
2:42
Speaker 1: every meal.
2:43
Speaker 3: Wow. So you must have like the best bean recipes?
2:46
Speaker 3: Can you send them to me?
2:48
Speaker 1: Absolutely? Yeah, we'll share some with.
2:49
Speaker 3: You because I got to say, after this conversation with Katrina,
2:52
Speaker 3: I am starting to think about how beans can be
2:54
Speaker 3: incorporated into every one of our dinners.
2:56
Speaker 1: At least we put lentils on everything. They're in salad
3:00
Speaker 1: and everything. They're fantastic. Yeah, we're big fans of beans.
3:02
Speaker 1: And our son loves beans too, which is a great outcome.
3:05
Speaker 3: You didn't mention your daughter. Does she not love beans?
3:07
Speaker 1: She's not yet on the bean wagon. Yep.
3:10
Speaker 3: You know it's hard to get kids on the bean wagon,
3:12
Speaker 3: I imagine. Yeah.
3:14
Speaker 1: Well, you know, with lots of foods, you can start
3:16
Speaker 1: with like the easier version, you know, like if you're
3:18
Speaker 1: gonna start drinking coffee, you put milk and sugar in it.
3:21
Speaker 1: I'm not quite sure what the easy way is with beans.
3:24
Speaker 1: Maybe put lots of cheese on top or something.
3:27
Speaker 3: At tacos has got to be tacos tacos.
3:29
Speaker 1: Yeah, exactly. Anyway, today we are talking about really fun
3:33
Speaker 1: and really important topics, what's going on inside our bodies
3:36
Speaker 1: and on our skin, about all those critters that are
3:39
Speaker 1: living with us or who are part of us.
3:42
Speaker 3: And you asked our listeners a question to gauge how
3:44
Speaker 3: subtly they understand the importance of bacteria in our bodies.
3:48
Speaker 3: So you ask them, do microbes hurt you or keep
3:51
Speaker 3: you healthy? And here's what they had to say.
3:54
Speaker 4: Microbes in your body are what allow you to function
3:57
Speaker 4: at all, So yeah, they're helpful, although some kinds of
4:02
Speaker 4: microbes are bad for you and they will hurt you both.
4:07
Speaker 5: There are good microbes and bad microbes.
4:10
Speaker 6: Providing the microbes in your body are kept under control
4:13
Speaker 6: in their number and their type, they can definitely help you.
4:17
Speaker 6: But if you get introduced microbes or the microbes get
4:21
Speaker 6: to a critical number, then they can also cause harm.
4:25
Speaker 5: Like most questions in biology, the answer is it depends.
4:29
Speaker 5: For example, your digestive system doesn't work without microbes, but
4:33
Speaker 5: if you have too many of the wrong ones, then
4:37
Speaker 5: it doesn't work at all, we.
4:39
Speaker 7: Couldn't live with the microbes in their body.
4:41
Speaker 8: I'm onto you now with your deliberately vague questions. So
4:46
Speaker 8: microbes in the body, I think what you wanted me
4:50
Speaker 8: to say was in the body, but not in the bloodstream. However,
4:56
Speaker 8: I think the research has changed on that, so I
4:59
Speaker 8: actually think you do have microbes in the bloodstream now,
5:03
Speaker 8: but by notche Yeah, they are good for you.
5:06
Speaker 2: I read somewhere that our bodies are whole ecosystems, so
5:10
Speaker 2: I would say that on the whole, the microbes are
5:15
Speaker 2: beneficial to us. Hope they do both.
5:17
Speaker 7: They help you and they can hurt you if they
5:19
Speaker 7: metestasize turn to cancer.
5:21
Speaker 9: Microbes in our body are good and help, but there
5:26
Speaker 9: might also be bad microbes that you could get that
5:29
Speaker 9: would make you sick.
5:31
Speaker 1: They can help or hurt or neither, or either one,
5:36
Speaker 1: depending on where it happens to be.
5:38
Speaker 10: I think the general rule of thumb is that the
5:40
Speaker 10: microbes that are in your body are there to help you,
5:43
Speaker 10: whereas the microbes that are trying to get into your
5:46
Speaker 10: body from the outside are the ones you gotta worry about.
5:49
Speaker 2: I believe the great majority of them are benign and
5:53
Speaker 2: useful microbes compared to the rare and wanted to intruders.
5:59
Speaker 1: Help, absolutely help.
6:01
Speaker 7: I can barely distinguish myself from my microbes.
6:05
Speaker 9: Finally, a question I can actually answer as a nurse.
6:08
Speaker 9: Microbes in the body can be harmful or beneficial. It
6:12
Speaker 9: depends on the type of microbe, the quantity of that microbe,
6:16
Speaker 9: and the location of that microbe.
6:19
Speaker 7: Both because some are bad for your body, like germs,
6:23
Speaker 7: and some are good for your body like good backter.
6:25
Speaker 11: Yet, there are forty trillion microbes in your body compared
6:31
Speaker 11: to thirty eight trillion human body cells in your body,
6:36
Speaker 11: and the majority of the microbes are there to make
6:40
Speaker 11: you feel better.
6:41
Speaker 1: And then every once in a while on the balance
6:43
Speaker 1: is out of whack. They get into stuff they're not
6:47
Speaker 1: supposed to do and cause us a little bit of damage.
6:50
Speaker 1: But hey, what areferens for?
6:52
Speaker 10: Microbes span the gamut from being critical for functioning to
6:57
Speaker 10: being lethal.
6:58
Speaker 12: We might not exist without micro It's something like ten
7:02
Speaker 12: times more microbes than human sells in the body. They
7:06
Speaker 12: help with digestion and glucose metabolism, help absorb nutrients in
7:11
Speaker 12: the body.
7:12
Speaker 7: Classic science answer it depends, Oh, this.
7:15
Speaker 9: Is a false dichotomy microbes both hurt and help you.
7:20
Speaker 5: I think microbes in our body are the part of
7:23
Speaker 5: our body.
7:24
Speaker 1: These are great answers. Thank you very much to our
7:26
Speaker 1: list of volunteers, and remember you can join them at
7:29
Speaker 1: any time. Just write to us two questions at Danielandkelly
7:32
Speaker 1: dot org and we will hit you up next time. Kelly,
7:36
Speaker 1: what did you think of these answers?
7:37
Speaker 3: I liked I can barely distinguish myself from my microbes.
7:40
Speaker 3: That made me smile. I wanted to learn more about
7:43
Speaker 3: the cancer and bacteria link. I don't know too much
7:46
Speaker 3: about that. Yeah, what about you? What was your favorite answer?
7:49
Speaker 1: I like the person who said that they're onto us
7:51
Speaker 1: with our deliberately vague questions. This whole thing is some
7:55
Speaker 1: kind of scheme. Yeah. I thought these were great, and
7:58
Speaker 1: they show that people have, all right, a pretty nuanced
8:01
Speaker 1: understanding of microbes. They're not just pathogens. They're part of
8:04
Speaker 1: who we are and how we live and all of
8:07
Speaker 1: our futures.
8:08
Speaker 3: All right, Well, I think it's time for us to
8:10
Speaker 3: dig in with the interview with our special guest today.
8:15
Speaker 1: So it's my pleasure to welcome back to the podcast,
8:17
Speaker 1: Katrina Whitson. She's the senior editor of the whites and
8:20
Speaker 1: Science Report quarterly journal, and she's the current holder of
8:24
Speaker 1: the whites In and Down Fellowship for actual experimental science,
8:27
Speaker 1: not just computer stuff. WHOA welcome to the pod.
8:31
Speaker 7: I don't think you guys understand what a big concession
8:34
Speaker 7: that was. There have been times at U see Irvine
8:37
Speaker 7: where there were three whites and labs. There was Daniel Whitson,
8:41
Speaker 7: who you all know and love, shimone Whiteson, his brother
8:44
Speaker 7: who is a computer science professor at Oxford but came
8:46
Speaker 7: into a sabbatical here. And then there was the actual
8:49
Speaker 7: whites Inn Lab Katrina Whitson, where there's like a physical
8:52
Speaker 7: lab and there's people in there growing microbes and glasswere
8:55
Speaker 7: being autoclaimed and stuff like that. It wasn't just like
8:58
Speaker 7: in the cloud. You know.
9:01
Speaker 1: Well went out here today to debate the philosophical question
9:04
Speaker 1: of whether stuff on the computer is actual answer or not.
9:06
Speaker 1: That's just me trying to butter you up.
9:08
Speaker 3: From the episode. I think we should bring you back
9:09
Speaker 3: for that debate.
9:10
Speaker 7: Though I know that what Daniel does is real science.
9:15
Speaker 7: I don't mean that. I'm just I'm just enjoying the.
9:17
Speaker 2: Joke, you know.
9:19
Speaker 1: I'm just glad to get that on the air. Wow,
9:20
Speaker 1: we have that requestion. So today we've invited you on
9:25
Speaker 1: the podcast because we're talking about microbes and microbes in
9:28
Speaker 1: the body and whether they help you when they hurt you,
9:30
Speaker 1: what their role is? Are they part of us? Are
9:33
Speaker 1: they our friend? Are their enemy? Are they our front
9:35
Speaker 1: of me? How does it all work? And this is
9:38
Speaker 1: your area of expertise that we're very happy to talk
9:40
Speaker 1: to you about it, But first let's get people acquainted
9:43
Speaker 1: and make sure everybody is talking about the same thing.
9:45
Speaker 1: Like when I say microbe, what does that mean to you?
9:48
Speaker 7: Well, microbes refer to life forms that are too small
9:52
Speaker 7: to see with the naked eye, but it can refer
9:55
Speaker 7: to like lots of different branches of the tree of life.
9:57
Speaker 7: So microbes can be viral, which we even debate whether
10:01
Speaker 7: they're alive or not. But they're definitely the most biologically
10:03
Speaker 7: diverse entity on the planet. So viruses, bacteria, fungi like yeast,
10:10
Speaker 7: other eukaryotic parasites like nightmarish ones that cause diarrhea. But
10:16
Speaker 7: most microbes are not pathogens. Even though most of what
10:18
Speaker 7: you hear about microbes are pathogens, most microbes actually are
10:23
Speaker 7: living their lives. Their goal is never to cause disease.
10:26
Speaker 7: They're out for themselves.
10:27
Speaker 1: You know, they have goals. You mean, like if you
10:30
Speaker 1: talk to them, they'd have like hopes and dreams.
10:32
Speaker 7: Well, I mean, I think all life forms have a
10:34
Speaker 7: basic goal of reproduction, whether they're like thinking about it
10:38
Speaker 7: or not.
10:39
Speaker 3: Could you give us a bit of our history on
10:41
Speaker 3: the thinking about this, Like, did we always think it
10:43
Speaker 3: was bad to have microbes in our gut? Have we
10:45
Speaker 3: kind of gone back and forth on thinking they're good
10:47
Speaker 3: or bad?
10:48
Speaker 7: Yeah, I mean definitely. Well, the first time we ever
10:51
Speaker 7: even saw microbe was when Van Lohenhook ground his own microscopes.
10:57
Speaker 7: He was a draper in the Netherlands, and he was
11:00
Speaker 7: grinding his own microscopes in order to look at the
11:02
Speaker 7: threads at the edge of the curtains he was making.
11:05
Speaker 7: But then for fun, he just took a piece of
11:07
Speaker 7: dental plaque, like a glop out of his mouth and
11:09
Speaker 7: looked at it, and he saw the little microbes jumping around,
11:12
Speaker 7: and he drew pictures of them. He called them animal tules.
11:15
Speaker 7: That's the first time we saw microbe. At that point,
11:17
Speaker 7: I think our thinking was pretty neutral. I mean, it
11:19
Speaker 7: took us a couple centuries to even realize that like
11:22
Speaker 7: washing hands was a good idea to prevent disease. So yeah,
11:26
Speaker 7: it was pretty neutral for a while. But then I'd
11:28
Speaker 7: say by the twentieth century, once cock postulates and we
11:32
Speaker 7: understood that microbes caused disease, then I think we were
11:35
Speaker 7: just expecting every time we turned a corner and discovered
11:37
Speaker 7: a new microbe that it was causing disease. And you
11:40
Speaker 7: might have heard of like bubble boy or in the
11:42
Speaker 7: nineteen fifties when we first developed notobiotic cultivation, we at
11:47
Speaker 7: that time thought like, wouldn't it be great if we
11:49
Speaker 7: could all be sterile. We really didn't imagine that the
11:51
Speaker 7: microbes were doing too much positive with a few exceptions,
11:55
Speaker 7: like there were people who appreciated probiotics around the year
11:58
Speaker 7: nineteen hundred, we.
12:00
Speaker 1: Go back, I want to understand what is nodobiotics and
12:03
Speaker 1: who's the bubble boy great.
12:05
Speaker 7: Noobiotics refers to cultivating animals in an intentional community of microbes.
12:12
Speaker 7: It doesn't actually have to mean sterile. It can often
12:14
Speaker 7: mean like intentionally cultivating say a mouse with like ten
12:18
Speaker 7: known microbes and then like learning exactly how those microbes
12:21
Speaker 7: affect immune development. And all other kinds of health outcomes.
12:25
Speaker 7: So noobiotics are a really important tool in microbiome science.
12:28
Speaker 7: Where we can intentionally cultivate mice or zebrafish or like
12:32
Speaker 7: pick your model animal of choice. We can't really do
12:35
Speaker 7: that with people though, With this exception of bubble Boy,
12:38
Speaker 7: who was a boy who had severe immune deficiency, and
12:44
Speaker 7: I mean kind of brilliantly, considering the technology available at
12:47
Speaker 7: the time, his medical community the doctors around him figured
12:51
Speaker 7: out how to keep him in essentially sterile conditions, like
12:54
Speaker 7: in a plastic bubble with oxygen pumped in, so that
12:58
Speaker 7: he was never exposed to microbes that would quickly kill him.
13:01
Speaker 7: There's a movie about it too, So that's pretty rare
13:04
Speaker 7: to have a human growing up with that little microbial exposure.
13:08
Speaker 7: But at that time, we thought like, oh, the more antibiotics,
13:10
Speaker 7: the more better. Just like pop them down, it'll probably
13:13
Speaker 7: help you. There was not really a feeling of loss
13:16
Speaker 7: that by taking antibiotics you were destroying something.
13:19
Speaker 3: And I feel like since then we've gone in the
13:21
Speaker 3: opposite direction where whenever you're listening to a podcast you
13:25
Speaker 3: get advertisements about bacteria that are so good for you,
13:29
Speaker 3: And have we sort of gone in the opposite direction.
13:32
Speaker 3: Are we finding a happy medium?
13:34
Speaker 7: That's a good question. I feel like the ads you
13:36
Speaker 7: hear are sometimes coming from the eighty billion dollar probiotic industry,
13:41
Speaker 7: which is not really resting upon too much evidence, to
13:44
Speaker 7: be honest, and so the kinds of things you hear
13:47
Speaker 7: in those ads are often not all that close to reality.
13:51
Speaker 7: So I guess it depends a little bit about which
13:53
Speaker 7: parts you're hearing about. I think the message that we
13:55
Speaker 7: shouldn't just pop antibiotics without any concern for the damage
13:59
Speaker 7: they can cause, I feel like that has gotten much better.
14:02
Speaker 7: So yeah, I think we have come to appreciate that
14:04
Speaker 7: taking antibiotics has a consequence that's not only positive. Although
14:08
Speaker 7: keep in mind that eighty percent of the antibiotics used
14:10
Speaker 7: in the United States at least are in agriculture, so
14:13
Speaker 7: our own human consumption can only have so much impact
14:16
Speaker 7: on avoiding the antibiotic resistance crisis.
14:19
Speaker 1: All right, So microbes are these little critters that are
14:21
Speaker 1: too small to see, which frankly feels to me like
14:24
Speaker 1: a little fuzzy, like if I have terrible vision, are
14:26
Speaker 1: there some things that are microbes to me? Like if
14:28
Speaker 1: I can't see cats to the count's microbes because I
14:30
Speaker 1: have like very bad eyesight. But as usual, it's biology,
14:34
Speaker 1: so it's fuzzy, no, I mean.
14:36
Speaker 7: It's definitely like you know, if I had a slide,
14:39
Speaker 7: I could give you some images of the scale bar
14:43
Speaker 7: and the sizes of viruses and bacteria. Like your average
14:46
Speaker 7: bacterial cell is about ten times smaller than your average
14:49
Speaker 7: eukaryotic cell. Eukaryotic cells have a nucleus. Those are the
14:53
Speaker 7: kind of cells that make up our bodies, and there's
14:54
Speaker 7: also unicellular versions of them. But I mean, yeah, the
14:58
Speaker 7: point is just that they're tiny, and they tend to
15:01
Speaker 7: be unicellular too.
15:03
Speaker 1: I mean some dogs are tiny too. Around la fit
15:06
Speaker 1: people's pursus dogs all.
15:09
Speaker 7: Right, those dogs have like four thousand times as many
15:13
Speaker 7: microbes in their guts, is what I'm saying, though, I.
15:16
Speaker 1: Mean toy dogs are pretty small. Anyway. You're the expert
15:19
Speaker 1: on it, So that's a And so you've walked us
15:23
Speaker 1: through this history where we learned about microbes. Some of
15:26
Speaker 1: them cause disease, but now we have a more nuanced take.
15:29
Speaker 1: So tell us, like, if microbes are part of us,
15:32
Speaker 1: where on the body do they live? Where can I
15:35
Speaker 1: find microbes in my body.
15:37
Speaker 7: I mean, you can find microbes literally everywhere, whether it's
15:40
Speaker 7: your body or not, and so that's actually a challenge.
15:44
Speaker 7: Sometimes I start my talks out with this challenge that,
15:47
Speaker 7: like a key postulate of microbial ecology is that nothing
15:50
Speaker 7: is sterile, and then I try to think of maybe
15:54
Speaker 7: exceptions to that, like places where life really can't be sustained.
15:57
Speaker 7: But I mean you could just check out and environment
16:00
Speaker 7: deep sea, ocean, vents, hot springs, you know, the outside
16:05
Speaker 7: of a spaceship, like.
16:07
Speaker 1: What about uranus is urinus sterile?
16:11
Speaker 7: Wow, Well that depends a bit on the meeting, but
16:17
Speaker 7: answer well, I think there are places that have very
16:22
Speaker 7: very low microbial load and some materials that can't really
16:27
Speaker 7: sustain microbial life so well, like maybe glass for example.
16:32
Speaker 7: But on average, you know, on your body, which was
16:34
Speaker 7: your question, we have really really dense microbial colonization in
16:38
Speaker 7: our gut. Those are mostly microbes that can't survive with oxygen,
16:42
Speaker 7: Like they're called anaerobes, so they live without oxygen. Most
16:46
Speaker 7: of the microbes in your gut are anaerobes, which I
16:48
Speaker 7: just think is amazing because we obviously live in a
16:49
Speaker 7: world with oxygen, so it's kind of crazy. How all
16:52
Speaker 7: these anaerobes colonize our bodies.
16:54
Speaker 3: We're reversed bubble boys for the bacteria in our guts.
16:57
Speaker 7: Yeah, exactly. Even your teeth have really strict anaerobes growing
17:01
Speaker 7: on them, so your oral cavity is super super densely
17:04
Speaker 7: colonized with microbes. Like the number of microbes per density
17:08
Speaker 7: is about the same in your oral cavity and in
17:11
Speaker 7: your gut, And like in a soil sample where they're
17:13
Speaker 7: famous for being teeming with microbes, and in your oral
17:17
Speaker 7: cavity there's just gradients of microbes that gobble up the
17:20
Speaker 7: oxygen at the surface, so that shields the ones underneath
17:23
Speaker 7: so that the anaerobs can survive.
17:25
Speaker 1: Why do you say oral cavity instead of mouth?
17:28
Speaker 7: Wow? I mean mouth is probably a better choice. I
17:31
Speaker 7: see what you're saying, But I guess I just got
17:33
Speaker 7: so used to writing papers about oral microbiomes and oral cavities,
17:36
Speaker 7: And like in the Human Microbiome Project, there were seventeen
17:40
Speaker 7: sampling sites in the oral cavity. There's symmetry, Like your
17:43
Speaker 7: two back top teeth on each side of your mouth
17:46
Speaker 7: have more similar microbial communities compared to ones closer to
17:49
Speaker 7: the surface having to do with like nutrient access, and
17:53
Speaker 7: so I think I'm just thinking about that.
17:54
Speaker 3: When I say it, we've gotten a little bit farther
17:57
Speaker 3: away from my favorite topic. So first I want to
17:59
Speaker 3: point out that Annuel was the first one to mention
18:01
Speaker 3: poop and butts in this episode, So I win.
18:04
Speaker 1: I win.
18:04
Speaker 3: You can't always blame the biologists. But I've been dying
18:07
Speaker 3: to ask you. So I heard that our bodies have
18:13
Speaker 3: so many microbes, that we have more microbes in our
18:16
Speaker 3: body than we do cells. But then I heard that
18:20
Speaker 3: the balance of power changes immediately following a bowel movement
18:24
Speaker 3: because there's so many bacteria in our feces. What is
18:29
Speaker 3: the truth, Katrina, I have to know.
18:31
Speaker 7: Wow, Well, that's an awesome question, and it's been a
18:34
Speaker 7: real topic of debate, and it's funny because it's like
18:37
Speaker 7: the intro slide to every microbiome talk for about ten
18:40
Speaker 7: years was all about how there's ten times as many
18:43
Speaker 7: microbial cells as human cells and an average human body.
18:47
Speaker 7: But then we redid our back of the envelope calculations,
18:50
Speaker 7: so now we call it front of the envelope, and
18:51
Speaker 7: now the ratio is estimated to be more like one
18:54
Speaker 7: to one, but like both the numerator and the denominator
18:58
Speaker 7: are like highly influx here. I wouldn't swear the life
19:01
Speaker 7: of my children on these calculations or anything like that,
19:04
Speaker 7: because it's.
19:04
Speaker 1: Really good too, but.
19:07
Speaker 7: Like even just estimating the number of cells in a
19:10
Speaker 7: human body.
19:11
Speaker 1: Wait, sorry, are there science conversations that you have that
19:13
Speaker 1: I'm not in where you are swearing the life of
19:15
Speaker 1: our children?
19:16
Speaker 7: No, definitely not.
19:19
Speaker 1: I mean, I gotta wonder now, Daniel.
19:21
Speaker 3: I feel like you're often on the show talking about
19:23
Speaker 3: dangerous situations you'd put the kids in for the sake
19:26
Speaker 3: of physics. I don't feel like you need to be
19:28
Speaker 3: high and mighty about this.
19:29
Speaker 1: I'm mostly talking about your kids, Kelly.
19:31
Speaker 3: Oh oh wow.
19:33
Speaker 7: Interesting.
19:34
Speaker 3: I'm sending my kids to their grandparents' house when you
19:37
Speaker 3: guys come to visit next week.
19:40
Speaker 1: All right, Sona, you're telling us there's a lot of uncertainty.
19:43
Speaker 1: We don't really even know whether there are more human
19:45
Speaker 1: or microbial cells in our bodies.
19:47
Speaker 7: I'd say that balance is closer to roughly even, and
19:50
Speaker 7: I agree that when you have a bowel movement, the
19:52
Speaker 7: balance would shift because you would lose a lot of
19:55
Speaker 7: microbial cells every time, depending how much fiber you eat
19:58
Speaker 7: and if you have really big bowel movements or not.
20:00
Speaker 7: But no matter what, despite the number of cells, what
20:06
Speaker 7: we can always say is that the diversity of metabolisms
20:10
Speaker 7: in our body is heavily weighted towards the microbes, because
20:14
Speaker 7: human cells can only pull off like a pretty small
20:18
Speaker 7: number of metabolisms. Like the number of types of genes
20:21
Speaker 7: is pretty small in comparison to the number of types
20:23
Speaker 7: of genes that microbes carry. Each microbe can live in
20:27
Speaker 7: a totally different niche, Like there's microbes that live with
20:30
Speaker 7: no oxygen or microbes that can live with a little
20:32
Speaker 7: bit of oxygen, and they each carry very unique genes
20:36
Speaker 7: for breaking down all kinds of molecules. So like, our
20:39
Speaker 7: metabolomic diversity is unquestionably much more coming from our microbes
20:44
Speaker 7: than from our human cells.
20:46
Speaker 1: All Right, So, I feel like we're transitioning from talking
20:48
Speaker 1: about individual microbes to talking about like communities and microbes.
20:51
Speaker 1: And you're telling us these live here and those live there.
20:54
Speaker 1: And you hear the word all the time these days,
20:56
Speaker 1: the microbiome. Yeah, so microbiome just a description of like
21:00
Speaker 1: microbial communities.
21:01
Speaker 7: Yes, exactly. So a microbiome is a community of the
21:05
Speaker 7: microbes we just defined in a particular environment. So the
21:10
Speaker 7: microbiome definition includes what the environment is. So like, the
21:14
Speaker 7: kind of microbes that live in your gut where there's
21:16
Speaker 7: not very much oxygen is very different than the kind
21:18
Speaker 7: of microbes that live at the surface of the ocean,
21:20
Speaker 7: where photosynthesis is a big deal. So it's about what
21:24
Speaker 7: type of life is sustained in that environment.
21:27
Speaker 1: So if I see like a bunch of ladies in
21:29
Speaker 1: LA with one hundred tiny little dogs that are so
21:33
Speaker 1: small that I can't see them, so those are all microbes,
21:36
Speaker 1: and together they make a little microbiome.
21:39
Speaker 7: I mean, I can't really just say yes to that.
21:43
Speaker 7: And you can't see the dogs. That means they're in
21:46
Speaker 7: your imagination. So then.
21:49
Speaker 1: They're philosophical dogs.
21:50
Speaker 7: You need some evidence to support your claims. I thought
21:53
Speaker 7: you were a scientist.
21:55
Speaker 1: Wow, I just do computer stuff.
21:57
Speaker 3: Actually, it's good to know that. Next time I'm Daniel
22:00
Speaker 3: and I have a conversation like this, it's okay to
22:02
Speaker 3: just say I'm not humoring that.
22:07
Speaker 7: Oh no, in theory, I see what you're saying, And like,
22:10
Speaker 7: only Los Angeles would support one hundred people with microscopically
22:14
Speaker 7: tiny dogs. So that's kind of special to that environment.
22:17
Speaker 1: I see your point, So then I want to connect
22:18
Speaker 1: it back to something you said earlier. You were talking
22:20
Speaker 1: about the kinds of microbes that live in different parts
22:22
Speaker 1: of our bodies. Do we have like one microbiome, like
22:25
Speaker 1: one community of microbes or are there different communities and
22:28
Speaker 1: microbes that live like in my oral cavity and on
22:32
Speaker 1: my gut or on the tip of my nose.
22:33
Speaker 7: Yeah, there's really big differences in the types of microbes
22:36
Speaker 7: that live in your gut versus your oral cavity versus
22:39
Speaker 7: like the dryer patches of your skin on your elbow
22:42
Speaker 7: versus the oil ear patches of your skin in another
22:46
Speaker 7: part of your body, like your armpits, say, and also
22:48
Speaker 7: super interesting most of our bodies. On the skin, we
22:51
Speaker 7: have a lot of diversity of bacteria, but on our feet,
22:54
Speaker 7: which are more moist, we actually have more diversity of fungi.
22:58
Speaker 7: And this is all in health anyway. If we start
23:01
Speaker 7: talking about transplants, which I imagine we will, there's fecal transplants,
23:05
Speaker 7: there's armpit transplants, there's ear microbiome transplants, and so getting
23:10
Speaker 7: a healthy community of microbes going is really important to
23:14
Speaker 7: our health. But even defining health, of course is really hard.
23:17
Speaker 3: Well, can we try to talk a little bit more then,
23:18
Speaker 3: about what these microbes are doing for us? So you
23:20
Speaker 3: mentioned that a bunch of the metabolism that happens in
23:23
Speaker 3: our body is caused by bacteria, and that sounds like
23:27
Speaker 3: it could be helpful. So what are some things that
23:30
Speaker 3: our bacteria do for us?
23:31
Speaker 12: Oh?
23:32
Speaker 7: What a great question. So I mean, to be honest,
23:34
Speaker 7: a lot of this is still unknown. So that's what's
23:36
Speaker 7: so fun about our field. I'd say most of the
23:38
Speaker 7: things that microbes are doing we don't know what they
23:41
Speaker 7: are yet. But things that they do, for example, are
23:45
Speaker 7: they can break down fiber. So when you eat fiber
23:48
Speaker 7: in your diet, actually human metabolism can't handle that at all,
23:53
Speaker 7: but the anaerobes living in your gut they're really good
23:55
Speaker 7: at breaking down fiber. And another example that I love
23:59
Speaker 7: is the sugars in breast milk. They should actually be
24:02
Speaker 7: called fibers as well. So in breast and milk, about
24:05
Speaker 7: fifteen percent of the energy is in the form of
24:08
Speaker 7: sugars or fibers that human metabolisms just can't access at all,
24:13
Speaker 7: but the microbes can. And so this is a really
24:15
Speaker 7: important moment in human history, Like what moment matters more
24:20
Speaker 7: than when a baby is born. That clearly we wouldn't
24:22
Speaker 7: just throw fifteen percent of the energy that's in breast
24:25
Speaker 7: milk down the drain unless it was really sustaining something important.
24:29
Speaker 7: And that fifteen percent of the energy in the breast
24:31
Speaker 7: milk is sustaining specific microbes that can break down the
24:36
Speaker 7: breast milk sugars. And then when a diaraleal pathogen comes
24:40
Speaker 7: through and tries to take up residents in a baby gut,
24:42
Speaker 7: it doesn't have access to that secret nutrient source. And
24:46
Speaker 7: so a big protection mechanism for babies in parts of
24:50
Speaker 7: the world where diarrheal illness is still a really big
24:52
Speaker 7: deal is if you're breastfed and you have those microbes
24:55
Speaker 7: that can break down the breast milk sugars, then the
24:58
Speaker 7: when salmonilla comes through, it was just kind of like cupping,
25:01
Speaker 7: and those special microbes like Biffido bacterias that can break
25:05
Speaker 7: down the breast milk sugars dominate the baby gut. That's
25:08
Speaker 7: probably how most baby guts were organized while they were
25:11
Speaker 7: breast fed through human history.
25:13
Speaker 1: So let me see if I understand you're telling me
25:15
Speaker 1: that basically the first step in digestion, like I eat
25:18
Speaker 1: a bowl of beans, it's not that my human mechanisms
25:21
Speaker 1: get involved and break the beans down, but like microbes
25:24
Speaker 1: are on the front line and they start the process
25:26
Speaker 1: breaking things down because.
25:27
Speaker 7: I can't the order of events there is a little different, Like, okay,
25:31
Speaker 7: so you're eating your beans, they get to your stomach,
25:33
Speaker 7: the stomach acid starts to break things down. Digestive enzymes
25:37
Speaker 7: come in from your pancreas and small intestine area. So
25:41
Speaker 7: actually the first chomp at most nutrients is coming from
25:45
Speaker 7: earlier steps in your digestive tract. And actually the microbial
25:49
Speaker 7: load is quite low, Like we do have microbes in
25:51
Speaker 7: our stomach, but at not very high density, and same
25:55
Speaker 7: with our small intestine. But by the time you get
25:57
Speaker 7: to the colon, so you need to eat food that
26:00
Speaker 7: don't get absorbed quickly earlier in your digestive tract to
26:04
Speaker 7: give your microbes access to them. So if you just
26:07
Speaker 7: eat white rice or processed foods, those get absorbed real
26:10
Speaker 7: quick in your stomach and small intestine. But if you
26:14
Speaker 7: eat things that take longer, then they get down to
26:17
Speaker 7: where the most dense community of microbes lives, and then
26:20
Speaker 7: you can give those microbes a chance to break down
26:23
Speaker 7: the fibers.
26:24
Speaker 1: I'm sure ken of these the questionbody, just want to
26:26
Speaker 1: ask one quick follow up about the baby thing. You're
26:28
Speaker 1: telling me that human mothers produce something that babies cannot
26:33
Speaker 1: digest without microbes in their guts, which means, of course
26:37
Speaker 1: that we've been doing this for a long long time. Yeah, right,
26:40
Speaker 1: microbes probably evolved with us. But how do babies get
26:43
Speaker 1: those microbes? Like, do they get them from the mom
26:45
Speaker 1: Is it during the birth, is it during gestation?
26:48
Speaker 7: It happens after birth, But actually there's probably many opportunities.
26:53
Speaker 7: When something's really important, it's good to have a lot
26:56
Speaker 7: of ways for it to happen, and so it's not
26:59
Speaker 7: just only at birth. It could be at birth, but
27:02
Speaker 7: I would imagine that in a village or a community
27:05
Speaker 7: in human histories past, where there were a lot of
27:08
Speaker 7: young children, that this would be passed between siblings and friends.
27:12
Speaker 7: I mean, you just need to be in an environment
27:14
Speaker 7: where that microbe exists. So it doesn't only have to
27:18
Speaker 7: be at the moment of birth. It could be at
27:19
Speaker 7: the moment of birth, but it could also be really
27:22
Speaker 7: at any time in the beginning of life.
27:24
Speaker 1: All right, Well, that takes us all the way back
27:26
Speaker 1: into prehistory and the understanding of microbes. And we're going
27:29
Speaker 1: to take a break and we're going to come back
27:30
Speaker 1: and we're going to talk about the present and the
27:32
Speaker 1: future of microbes.
27:51
Speaker 3: And we're back, and okay, Katrina, I have a question
27:53
Speaker 3: for you that I get asked a lot, and I
27:55
Speaker 3: would love to know what the answer should be. So
27:58
Speaker 3: I study parasites that manipulate the behavior of their house
28:01
Speaker 3: and often people will say, Okay, I've heard that our
28:04
Speaker 3: brains have nerves that go down to our stomach, and
28:07
Speaker 3: that bacteria do things like release serotonin and dopamine that
28:11
Speaker 3: can communicate with our brains. So are our behaviors controlled
28:17
Speaker 3: by our microbiome? Can our microbiome be like you need
28:20
Speaker 3: to eat more beans or something? So to what extent
28:25
Speaker 3: are our microbes influencing our behavior?
28:27
Speaker 7: Well, I mean a lot. For sure. There's definitely a
28:31
Speaker 7: very strong gut brain axis, and we've known that for
28:35
Speaker 7: a long time. Even independent of the microbes, we know
28:38
Speaker 7: that a lot of our nervous and immune system is
28:42
Speaker 7: in our gut, and so ninety percent of the serotonin
28:45
Speaker 7: in your body is produced in your gut, for example,
28:48
Speaker 7: and it's with the help of neuroendocrine cells in our guts,
28:53
Speaker 7: but those cells are being manipulated by the microbes. So
28:57
Speaker 7: there's a really strong connection between the dense community of
29:01
Speaker 7: microbes in our guts and all of the different types
29:04
Speaker 7: of cells lining our guts that are interacting with our
29:08
Speaker 7: nervous system. So there is a very strong gut brain connection,
29:12
Speaker 7: no question. And there's so much interesting evidence which is
29:16
Speaker 7: hard to sort through about how if you improve your
29:18
Speaker 7: diet you can improve symptoms of depression, or if you
29:22
Speaker 7: meditate regularly you can improve your inflammatory state and your
29:27
Speaker 7: microbiome composition.
29:29
Speaker 1: Where you're saying, it goes both directions, not just microbes
29:31
Speaker 1: or influencing how we think. But your brain can like
29:33
Speaker 1: control the microbe somehow.
29:35
Speaker 7: I mean when you say it like that, it sounds fantastical,
29:39
Speaker 7: but I mean I literally just watched Joe Handlesman give
29:42
Speaker 7: a talk last week about how people who were meditating
29:45
Speaker 7: regularly had improvements in their microbiome, and defining an improvement
29:49
Speaker 7: is a really hard thing to do in our field.
29:51
Speaker 7: So you know, ask more questions if you want, but yes,
29:54
Speaker 7: it goes in every direction. Because our microbe composition is
29:58
Speaker 7: influenced by the environment, and if you do things that
30:02
Speaker 7: helped to change your stress levels and the types of
30:07
Speaker 7: inflammatory cells that your body is inhabited by, then that
30:10
Speaker 7: changes the environment, and it changes which microbes are winning
30:15
Speaker 7: the battle of survival in your gut at that moment,
30:18
Speaker 7: and which microbes are there to break down the foods
30:21
Speaker 7: that you're eating. So, yeah, there's a very tight connection
30:25
Speaker 7: between our guts and our minds. But we're really at
30:28
Speaker 7: the beginning of figuring that out. There's a few conditions
30:32
Speaker 7: that we are starting to have really good evidence, like
30:35
Speaker 7: for Parkinson's disease, there's symptoms in the gut arising well
30:39
Speaker 7: before other symptoms like constipation, and that was one of
30:43
Speaker 7: the clues that helped us try to disentangle how the
30:46
Speaker 7: microbiome is involved in Parkinson's disease development. I'm so curious
30:51
Speaker 7: in ten years, like what we're going to understand better.
30:54
Speaker 7: But there's really cool evidence emerging all the time.
30:57
Speaker 1: So you've mentioned several times that the microbe was played
31:00
Speaker 1: roles in digestion, et cetera. Do we know what like
31:03
Speaker 1: a good microbiome is, Like, do we understand what your
31:07
Speaker 1: microbiome should be doing and what its composition should be,
31:11
Speaker 1: and is that true in the gut or am my
31:14
Speaker 1: nose or my ear.
31:16
Speaker 7: That is still a science question, and I think it's
31:18
Speaker 7: also maybe a philosophy question. Even just to define health
31:22
Speaker 7: is really interesting, and our field has had a lot
31:24
Speaker 7: of interaction with philosophers through the years to try to
31:28
Speaker 7: define what health is. For example, at the operation nearby
31:34
Speaker 7: in Testine for the product to VOUST, where they harvest
31:38
Speaker 7: so called healthy fecal spores from so called healthy donors
31:42
Speaker 7: in order to treat the diarrheal pathogen c DIFF. They
31:46
Speaker 7: have to decide who can be a healthy donor and
31:49
Speaker 7: they screen people and only one percent are considered eligible.
31:53
Speaker 1: To be clear, what we're donating here, are bms right?
31:56
Speaker 7: Yes, So they get volunteers to come and poop on
31:58
Speaker 7: site four to six times per week and then they
32:00
Speaker 7: harvest the spores out of their poop and that is
32:03
Speaker 7: the product VOUST, which is being used to treat se DIFF.
32:06
Speaker 7: It's one of two FDA approved microbiome therapies in the
32:09
Speaker 7: country right now.
32:10
Speaker 3: It's got to be hard to schedule, like you can't
32:12
Speaker 3: just do that on cue. My son seems to be
32:14
Speaker 3: able to. But he's the only one I've ever met
32:16
Speaker 3: who can do that.
32:17
Speaker 7: Yeah, I think they have like a big line in
32:19
Speaker 7: the morning. So people who can do that regularly. I
32:22
Speaker 7: remember asking in one of my classes ones like, who
32:25
Speaker 7: knows when they're gonna poop every day? Like, is it
32:27
Speaker 7: like something you know when it's gonna happen, or is.
32:29
Speaker 1: It like you're asking people about this in class and
32:31
Speaker 1: public that like raise their hand to talk about their
32:33
Speaker 1: poop schedule.
32:34
Speaker 7: Well, it was when I had somebody from the company
32:37
Speaker 7: Voused visiting to speak and she had exactly the question
32:39
Speaker 7: you just had, Kelly. Anyway, there were some people who
32:42
Speaker 7: were like, how could you not know when you're gonna poop?
32:44
Speaker 7: I always know when? And other people who were like,
32:46
Speaker 7: I would never be able to guess that. That's clearly
32:48
Speaker 7: like something that's different about each person.
32:50
Speaker 2: Huh.
32:50
Speaker 7: But you know, one percent of people are not the
32:53
Speaker 7: only healthy people. And I think that we need to
32:56
Speaker 7: think about what we mean by health differently. When I'm
32:58
Speaker 7: writing my ethics view approval documents for the studies that
33:02
Speaker 7: I do, I have a very expansive definition of what
33:05
Speaker 7: I think health is, And to me, health is someone
33:08
Speaker 7: who's out and about living their life, like a student
33:11
Speaker 7: in my class is definitely considered healthy that otherwise they
33:14
Speaker 7: couldn't like show up and be a college student if
33:16
Speaker 7: they have some allergy or some other kind of defined
33:20
Speaker 7: disease it's been diagnosed. In my mind, that doesn't like
33:22
Speaker 7: knock them out of the category of being a healthy person.
33:25
Speaker 7: And so that's a really difficult question to answer. But
33:29
Speaker 7: your question was do we know what a healthy microbiome is?
33:31
Speaker 7: And that was actually what the goal of the Human
33:34
Speaker 7: Microbiome Project was. It started in two thousand and six
33:37
Speaker 7: and they got three hundred healthy donors in the United
33:39
Speaker 7: States to give samples, and healthy was defined somewhat more inclusively,
33:45
Speaker 7: I think than the one percent that were accepted in
33:47
Speaker 7: that other donation context. And the goal was, like, what's
33:51
Speaker 7: the core human microbiome? Like, what are microbes that are
33:54
Speaker 7: shared between everyone? And the fascinating thing was that every
33:58
Speaker 7: time you added one more to the study, the then
34:01
Speaker 7: diagram overlap got smaller and smaller until there was nothing left.
34:05
Speaker 7: So there were no core human microbes. Everybody is different
34:08
Speaker 7: enough that there just really isn't a core human microbiome,
34:11
Speaker 7: depending how you define it.
34:13
Speaker 1: So you're saying, for example, person A is totally healthy
34:17
Speaker 1: and living their lives and having great poops and doesn't
34:20
Speaker 1: have anything in common gut bacteria wise with person B,
34:23
Speaker 1: who's also healthy and can eat beans and doesn't have
34:27
Speaker 1: terrible digestive problem.
34:28
Speaker 7: Yeah, people are extremely different from each other. If you
34:31
Speaker 7: only had two people, I bet you would find some overlap.
34:33
Speaker 7: But by the time you get to about ten people,
34:36
Speaker 7: you probably don't have much overlap left anymore. And then
34:39
Speaker 7: really big differences occur when you look around the world,
34:42
Speaker 7: and so there's really cool patterns of people who live
34:45
Speaker 7: in less industrialized places, where they eat more plants and
34:49
Speaker 7: less processed food, their guts tend to be dominated by
34:52
Speaker 7: plant breakdown microbes that are good at breaking down fiber
34:56
Speaker 7: and probably have other properties too, Whereas if you look
34:59
Speaker 7: in the industry world, and this is like so scary
35:02
Speaker 7: to meet that most people in the industrialized world have
35:05
Speaker 7: a lot of mucus breakdown bugs in their gut. So
35:08
Speaker 7: basically we're starving our guts of fiber, and as a result,
35:12
Speaker 7: the microbes are like turning to us and just like
35:15
Speaker 7: eating the mucus that's produced by the cells lining our gut.
35:19
Speaker 7: So there's this bug called Acromancia that's very common in
35:21
Speaker 7: the industrialized world, and bizarrely, it's even marketed as a
35:26
Speaker 7: probiotic because it has been associated with positive outcomes. But
35:30
Speaker 7: it's breaking down the mucus, which is the only thing
35:33
Speaker 7: between you and sepsis. You have like literally millions of
35:37
Speaker 7: cells of microbes in your colon and there's one layer
35:40
Speaker 7: of cells, this epithelial lining of cells lining your gut,
35:45
Speaker 7: and if that barrier breaks down, the microbes get into
35:48
Speaker 7: your blood and that's the blood infection that's called sepsis.
35:50
Speaker 7: That's deadly. And so your mucus lining, that one layer
35:54
Speaker 7: of cells is a really important part of the barrier
35:57
Speaker 7: protecting you. And so we're we have a lot of
36:01
Speaker 7: bugs that are breaking down that mucus. Maybe there's some
36:04
Speaker 7: kind of feedback there. I mean, these are all science questions. Maybe,
36:07
Speaker 7: like the bugs breaking down the mucus stimulate its production,
36:10
Speaker 7: and maybe that's not all bad. But just the fact
36:13
Speaker 7: that it's so common in the industrialized world and missing
36:17
Speaker 7: in the parts of the world where people eat more plants,
36:19
Speaker 7: it kind of makes me want to have the plant
36:21
Speaker 7: type of microbiome, not the mucus breakdown one.
36:24
Speaker 1: So then where can we expect similarities between microbiomes? Like
36:28
Speaker 1: you and I live in the same house, you mostly
36:29
Speaker 1: use similar foods, use the same toilets. Do we have
36:32
Speaker 1: similar microbiomes? Do we expect them to be similar?
36:34
Speaker 7: Definitely. That's one of the biggest signatures in every microbiome study,
36:38
Speaker 7: after the individual, is the household and the family. So
36:41
Speaker 7: when you collect samples from people who live together, they
36:44
Speaker 7: have so much in common, and so that's a really
36:48
Speaker 7: really cool way to do a study. Like my favorite
36:50
Speaker 7: way to do a study is with household controls, so
36:53
Speaker 7: you can compare people with the same background, and otherwise
36:56
Speaker 7: to do longitudinal studies where you take samples from the
36:59
Speaker 7: same person through an intervention and then use their starting
37:02
Speaker 7: point samples as the baseline, because if you try to
37:05
Speaker 7: do it cross sectionally where everyone is so different, it
37:07
Speaker 7: just doesn't work at all. And back to the household question.
37:10
Speaker 7: I mean, I really love studies that get into that.
37:14
Speaker 7: And I have a friend down in San Diego, David Pride,
37:17
Speaker 7: and he did a study once where he compared married
37:20
Speaker 7: couples who'd been living together for a long time with
37:23
Speaker 7: Craigslist roommates who moved in together, and after six weeks
37:27
Speaker 7: they shared a quarter of the viruses in their gut communities.
37:31
Speaker 7: So sharing a kitchen and a bathroom is enough to
37:34
Speaker 7: share a lot, huh.
37:35
Speaker 1: The Craigslist connection, Yeah, yep.
37:37
Speaker 3: How much do our own individual microbiomes change over time?
37:41
Speaker 3: So if you looked at a family now or five
37:43
Speaker 3: years down the road, how consistent would their microbiome be.
37:47
Speaker 7: They're quite consistent through time in families and households, but
37:51
Speaker 7: they're evolving because you know, microbes have high mutation rates.
37:56
Speaker 7: They don't correct themselves as much as ourselves do. So
38:00
Speaker 7: in a virus community, for example, there was one grad
38:03
Speaker 7: student who took samples from himself throughout grad school, which
38:06
Speaker 7: took a couple of years, and between the beginning and
38:09
Speaker 7: end of grad school, some of the viruses in their gut.
38:12
Speaker 7: I'm sure it was anonymous, so maybe I shouldn't say
38:14
Speaker 7: the name of this dadue. But anyway, some of the
38:17
Speaker 7: viruses had mutated more than three percent in their genomes,
38:21
Speaker 7: which is the definition of a new virus. Each of
38:23
Speaker 7: our guts is kind of like its own little chema
38:25
Speaker 7: stat where evolution can keep happening, and so through time,
38:30
Speaker 7: enough mutations arise that it could even be considered a
38:32
Speaker 7: new species of virus that's emerging. The other thing that
38:36
Speaker 7: happens is like say you travel and get diarrhea and
38:38
Speaker 7: really shake things up, or you take antibiotics, you can
38:41
Speaker 7: kind of like get your community steering to take a
38:46
Speaker 7: sharp turn after things like that.
38:48
Speaker 1: Wait, walk us through what's happening there, Like when you
38:50
Speaker 1: get diarrhea or you get seedp what's going on there?
38:53
Speaker 1: Something is coming in and out competing the microbes in
38:56
Speaker 1: our guts or what's going on?
38:58
Speaker 7: Yeah, exactly. So oftentimes a diarrheal pathogen, what will happen
39:03
Speaker 7: is that they'll come in with some toxin or some
39:06
Speaker 7: like really big hammer that causes big.
39:09
Speaker 1: Changes, meaning that it kills the other microbes.
39:12
Speaker 7: Or that it just triggers an enormous immune response, which
39:16
Speaker 7: brings in a lot of oxidative stress. And I was
39:19
Speaker 7: just telling you how the microbes in our colon's hate oxygen.
39:22
Speaker 7: Well inflammation is basically a pile of oxygen. So bringing
39:27
Speaker 7: in all those inflammatory cells and molecules, that's a tough
39:32
Speaker 7: condition for a lot of the bugs that live in
39:34
Speaker 7: our gut. And then you'll have an outgrowth of the
39:38
Speaker 7: kinds of bugs that can tolerate oxygen. In fact, when
39:41
Speaker 7: you study the microbiomes of people who have a terrible
39:44
Speaker 7: gut infection, you don't often find that the bug causing
39:48
Speaker 7: the infection is the most numerous. This really surprised me. Actually,
39:51
Speaker 7: I've done a few studies like this with lustratia deficial
39:54
Speaker 7: infections here at the CI Medical Center, and my naive
39:58
Speaker 7: expectation was that you I see like, oh, it's ninety
40:01
Speaker 7: percent seed difts, so they have a sea diff infection.
40:03
Speaker 7: But that's not what you see at all. You just
40:05
Speaker 7: see a bunch of bugs that can handle oxygen basically,
40:08
Speaker 7: and then there's probably a small number of sea diff
40:11
Speaker 7: cells that are just dumping toxin that's causing all that inflammation.
40:15
Speaker 1: That's really mind blowing, I mean, especially if you start
40:18
Speaker 1: from the point of view of like, diseases are microbes
40:22
Speaker 1: that come in, pathogens come in and colonize the humans.
40:25
Speaker 1: Now you're giving us a whole new way to think
40:27
Speaker 1: about what disease is. Now it's like microbial war where
40:31
Speaker 1: what's really being damaged are not the human cells, but
40:33
Speaker 1: like the microbes on our side that were doing their
40:36
Speaker 1: job for us.
40:37
Speaker 7: Yep.
40:38
Speaker 1: So it's really we're sort of like a host. We're
40:40
Speaker 1: just like the battleground for this microbial confrontation.
40:43
Speaker 7: Yeah, exactly. I really like the concept of a holo biome,
40:47
Speaker 7: which is the idea that you know, you are your
40:51
Speaker 7: own genome and cells, and then you are host to
40:55
Speaker 7: a community of microbes which comes from the environment that
40:59
Speaker 7: you live in. So all the microbes in the environment
41:02
Speaker 7: that you live in, and then some subset of them
41:04
Speaker 7: colonizes you. And so part of your environment is your diet,
41:08
Speaker 7: and part of it is like how much time you
41:10
Speaker 7: spend playing with dirt, so like your exposure to microbes.
41:13
Speaker 7: Who your roommates are, you know, stuff like that. Like
41:16
Speaker 7: sometimes people ask me, well, how can I get a
41:18
Speaker 7: healthy microbiome if I don't have one yet, And like
41:20
Speaker 7: one piece of advice would be to get a really
41:22
Speaker 7: healthy roommate who you knew how to help.
41:28
Speaker 1: You didn't cause a lot of stress here. People are
41:29
Speaker 1: gonna blame their diarrhea on their roommates. Now, if you
41:33
Speaker 1: only did the dishes, then I wouldn't have diarrhea.
41:37
Speaker 3: Or maybe you cleaned the bathroom too much. I needed
41:39
Speaker 3: your good microbes submand at them for that. So I've
41:42
Speaker 3: got a question about how we even quantify microbiome. So bacteria,
41:47
Speaker 3: you know, they can undergo conjugation, so they swap genetic
41:49
Speaker 3: material with each other. In just the course of a
41:51
Speaker 3: couple of years, viruses are becoming new species because they're
41:54
Speaker 3: mutating so much. How do you define a species when
41:59
Speaker 3: things are changing so quickly, and how do you compare
42:01
Speaker 3: between individuals when there's all this variability.
42:05
Speaker 7: Yeah, what a great question. And like I've been in
42:08
Speaker 7: this field long enough that I've watched the pendulum swing
42:10
Speaker 7: back and forth on how we make those definitions. Sometimes
42:13
Speaker 7: it's driven a little bit by technology, but you know,
42:16
Speaker 7: basically there have been people thinking about microbial communities for
42:21
Speaker 7: more than a century. So it goes back to there
42:24
Speaker 7: was a Ukrainian microbial ecologist who was studying pond scum
42:29
Speaker 7: in Switzerland and he made these columns called Winnegradsky columns,
42:32
Speaker 7: which had you know, just what I was talking about
42:34
Speaker 7: with the oxygen gradients, where you'd have oxygen loving bugs
42:38
Speaker 7: at the top and then their waste products become the
42:41
Speaker 7: treasure of the next layer of microbes which need less
42:44
Speaker 7: oxygen and have different strategies for metabolism. So those layers
42:49
Speaker 7: of microbes, you could even consider them to be the
42:52
Speaker 7: unit of selection that matters, and so it could be
42:55
Speaker 7: defined functionally. Almost since the mid twentieth century started having
43:00
Speaker 7: molecular techniques for probing all of the microbes in a community,
43:04
Speaker 7: and this all started with environmental microbiologists. All the human
43:07
Speaker 7: clinical microbiology people were too busy isolating one pathogen at
43:11
Speaker 7: a time and throwing anything that they didn't define as
43:13
Speaker 7: a pathogen down the drain as like unrelevant normal flora
43:17
Speaker 7: or something like that. So the environmental microbiologists got really
43:20
Speaker 7: good at these really cool molecular techniques, starting with less resolution,
43:25
Speaker 7: so they had to define a species based on the
43:28
Speaker 7: information they could get. So we started like digesting common
43:32
Speaker 7: genes like ribosomal genes, and using restriction enzymes that we
43:38
Speaker 7: got out of hot springs and putting them on gels,
43:41
Speaker 7: and then like if the bands on the gel looked different,
43:44
Speaker 7: then that would be defined as a different species. So
43:46
Speaker 7: probably we're talking like a few percent difference in genome
43:50
Speaker 7: because we were only looking at one gene. Even if
43:53
Speaker 7: that one gene is exactly the same, there could still
43:55
Speaker 7: be millions of years of evolution separating those two organisms.
44:00
Speaker 7: Then we got much better. Now we can sequence everything.
44:03
Speaker 7: And so when I first started in this field around
44:06
Speaker 7: two thousand and eight or so, we defined a bacterial
44:09
Speaker 7: species as being three percent different from the next in
44:13
Speaker 7: this one ribosomal gene. And that was how we defined
44:16
Speaker 7: a species. Since then, as our techniques have gotten better,
44:20
Speaker 7: we've leaned towards using even tighter definitions. So we could,
44:25
Speaker 7: you know, look at organisms that are almost identical and
44:29
Speaker 7: only have one nuclear hide difference, and then we would
44:31
Speaker 7: start to define that as the taxonomic unit that mattered.
44:36
Speaker 1: Because these guys reproduce asexually.
44:38
Speaker 7: Right, yeah, they reproduce asexually, but they have pretty high
44:41
Speaker 7: mutation rates. They don't like correct all their mistakes. So
44:44
Speaker 7: you know, for a virus, every progeny is immutant basically,
44:51
Speaker 7: I mean, think about that for flu or covid, Like
44:53
Speaker 7: I think there were actually really great visualizations about that
44:56
Speaker 7: since the pandemic that helped that become obvious to everybody.
45:00
Speaker 7: Which is so interesting, Right, if every time a virus
45:03
Speaker 7: makes a copy, it's a new mutant. Some of those
45:06
Speaker 7: just fall flat, But that's not the strategy. The strategy is,
45:09
Speaker 7: like most of them do okay, some of them do amazing.
45:12
Speaker 1: Well, hey, look, I'm sure those virus parents love all
45:14
Speaker 1: their little mutants.
45:17
Speaker 3: All right, So let's take a break and think about
45:19
Speaker 3: the mutants in our life that we love, and when
45:22
Speaker 3: we come back, we'll talk more about the microbiome.
45:43
Speaker 1: All right. So we're back, and we're talking to Professor
45:46
Speaker 1: Katrino Whitson of the Whites and Research Institute about the
45:49
Speaker 1: microbes in our body, how they influence our world and
45:52
Speaker 1: shape our lives. And we're talking about the links between
45:55
Speaker 1: microbiome and health. And in a minute, I want to
45:58
Speaker 1: ask you about what we can do to packed our microbiome.
46:01
Speaker 1: But you sort of laid out this picture that like
46:03
Speaker 1: these things are in our guts. We don't really understand
46:06
Speaker 1: why they're so different from person to person. We can't
46:08
Speaker 1: even really define health. We don't understand necessarily what microbiome
46:11
Speaker 1: you need to have healthy function. But we know that
46:13
Speaker 1: there's a connection between microbiome and health, right, And I've
46:17
Speaker 1: heard about people talk about connections between like the microbiome
46:20
Speaker 1: and like Alzheimer's or microbiome and autism and microbiome and
46:25
Speaker 1: all sorts of things in our lives. How much do
46:27
Speaker 1: we know about the impact of the microbiome on these.
46:30
Speaker 3: Conditions, Can I super fast interject. I love that Katrina
46:34
Speaker 3: is president of the Whites and Institute, but I do
46:37
Speaker 3: feel like we've never actually mentioned that Katrina is also
46:40
Speaker 3: a professor at UC Irvine and has her own lab.
46:42
Speaker 3: Have we given her actual credentials at some point?
46:46
Speaker 1: She does have a secondary affiliation that you see Irvine.
46:49
Speaker 3: Okay, all right, so she is incredible in lots of ways.
46:52
Speaker 3: But okay, all right, sorry, go ahead with the question.
46:55
Speaker 7: That's nice of you. Well, I mean, yes, we have
46:59
Speaker 7: observation evidence associating microbiomes with health on a lot of
47:04
Speaker 7: different fronts, and I mean just it's hard to even
47:07
Speaker 7: know where to start. But one place I could start
47:08
Speaker 7: is that when I started my lab at EC Irvine
47:10
Speaker 7: in twenty fourteen, right when microbiome was becoming big in
47:14
Speaker 7: the literature and everybody was excited about it, I had
47:17
Speaker 7: one hundred labs contact me wanting to collaborate. In that
47:21
Speaker 7: first year, I think I had one grad student just
47:23
Speaker 7: beginning to join my lab. We obviously couldn't do one
47:25
Speaker 7: hundred collaborations, so I ended up joining forces with an
47:28
Speaker 7: ecologist here, Jennifer Martini, and we started a Microbiomes center,
47:32
Speaker 7: and in the last ten years I have gotten to
47:34
Speaker 7: study easily one hundred different types of microbiomes. Like name
47:39
Speaker 7: a type of body example you could think of, I've
47:41
Speaker 7: probably got some in our lab freezer, and I've probably
47:43
Speaker 7: studied it's microbiome. And that goes for like lots of
47:46
Speaker 7: different kinds of creatures, including sharks that eat seaweed from
47:50
Speaker 7: Donovan German's lab, for example. So we have been going
47:54
Speaker 7: around and like watching what the microbiomes look like and
47:58
Speaker 7: taking notes and associating that way health. So a lot
48:01
Speaker 7: of the information we have is observational. So we still
48:04
Speaker 7: have in the future a need to do more interventional
48:08
Speaker 7: studies where we ask how does the microbiome change when
48:11
Speaker 7: you manipulate it in a certain way. You know, now
48:13
Speaker 7: we kind of know that microbiomes are associated with obesity
48:17
Speaker 7: and cancer and so forth, But then what do we
48:19
Speaker 7: do about it? That's kind of like the next ten
48:21
Speaker 7: years of challenge. And there's a few glimmers of really
48:24
Speaker 7: really exciting outcomes that make me think it's going to
48:28
Speaker 7: be possible. So, like, for example, cancer treatment is an
48:32
Speaker 7: area that I think has a lot of room for
48:35
Speaker 7: big improvement where my colleagues at m D Anderson gen Wargo,
48:39
Speaker 7: for example, have done studies showing that when melanoma patients
48:43
Speaker 7: are getting immunotherapy, which usually only succeeds about thirty percent
48:47
Speaker 7: of the time, and the thirty percent of people who
48:49
Speaker 7: have a successful immune therapy tend to have a certain
48:52
Speaker 7: kind of microbiome. Well, it turns out if you do
48:54
Speaker 7: a fecal transplant from someone who's immunotherapy succeeded into someone
48:59
Speaker 7: who's immunotherapy failed, you increase their chances of a good outcome.
49:04
Speaker 7: Or if you ask how much fiber people ate, people
49:06
Speaker 7: who ate more than twenty grams of fiber per day
49:09
Speaker 7: have double the progress free survival when they're doing immunotherapy.
49:13
Speaker 7: And now they're even doing intervention studies where they're getting
49:16
Speaker 7: people on immunotherapy to eat fiber and they're watching to
49:19
Speaker 7: see if that increases their healthy outcomes. And that's not
49:23
Speaker 7: published yet, but I'm very optimistic. So those are the
49:27
Speaker 7: kinds of things I could see happening in the future.
49:29
Speaker 7: We even know that vaccine efficacy depends on fiber intake,
49:33
Speaker 7: so like if you want to have a good response
49:34
Speaker 7: to a vaccine, eating well and Having enough plant fiber
49:38
Speaker 7: to support your gut microbes and keep your immune system
49:41
Speaker 7: going will actually make you have a more robust response
49:44
Speaker 7: to a vaccine.
49:45
Speaker 1: See. I knew tacos are good for you. I always
49:48
Speaker 1: knew that tacos.
49:49
Speaker 3: Exactly what are you putting in your tacos? Why are
49:51
Speaker 3: your tacos high fiber? Oh? Oh, I see not all
49:55
Speaker 3: tacos have beans in them, Daniel.
49:57
Speaker 1: Real tacos. Are you having like weird virgin the tacos
50:00
Speaker 1: with beans?
50:01
Speaker 3: I guess?
50:01
Speaker 7: So, yeah, I guess even Texans put beans in their chili.
50:06
Speaker 1: Yeah, no, exactly no, No, Texans have no beans in
50:09
Speaker 1: their chili. That's very important contrining.
50:11
Speaker 7: Okay, well, all.
50:13
Speaker 1: Right, So you've mentioned a few ways that we can
50:15
Speaker 1: impact our microbiome. Let's dig into those in detail. So
50:18
Speaker 1: you've talked a couple of times about fecal transplants, and
50:21
Speaker 1: people are probably wondering, like, what are you talking about here?
50:23
Speaker 1: When I think about transplant, I think about taking a
50:25
Speaker 1: kidney out of one person's body and putting it in
50:27
Speaker 1: somebody else's body. Now I'm trying to think about what
50:30
Speaker 1: a fecal transplant means. Like, walk us through this what's
50:33
Speaker 1: going on here? How does this work at all? What
50:35
Speaker 1: do we know about it?
50:36
Speaker 7: Okay, well, fecal transplants refer to taking a healthy microbiome
50:42
Speaker 7: from one person and trying to give it to another person.
50:45
Speaker 7: We have been doing this since ancient times, so more
50:48
Speaker 7: than a thousand years ago in China, people were using
50:50
Speaker 7: what they call golden soup to treat diarrhea. And actually,
50:57
Speaker 7: since I teach about this in my big classes, and
50:59
Speaker 7: I've heard so many good stories from my students who
51:02
Speaker 7: bring up, Oh, yeah, my family's from the South and
51:04
Speaker 7: we used to do cow Patty's tea to treat diarrhea.
51:09
Speaker 1: What really, Yeah, Southern hospitality there you go.
51:12
Speaker 3: Yeah, you guys have a lot to look forward to
51:14
Speaker 3: when you come to visit.
51:17
Speaker 7: I mean, this is something you would only do when
51:19
Speaker 7: you're in dire streets, right, But if you've been having
51:21
Speaker 7: diarrhea and you weigh sixty five pounds and you can't walk,
51:25
Speaker 7: you might be up for trying something bizarre to survive,
51:28
Speaker 7: you know. And so actually, a modern time story comes
51:31
Speaker 7: from the Mayo Clinic in Minnesota, where a woman who
51:35
Speaker 7: had a sea diff infection. Sea diff is typically caused
51:37
Speaker 7: by taking antibiotics and decimating your healthy microbiome, which makes
51:41
Speaker 7: it easy for sea diff which forms spores in your gut,
51:44
Speaker 7: to rear its head and make toxins and cause diarrhea,
51:48
Speaker 7: and it can get really recurrent and difficult to treat.
51:51
Speaker 7: And the standard of care, ironically is more antibiotics, which
51:54
Speaker 7: caused the problem in the first place. So a woman
51:57
Speaker 7: at the University of Minnesota at the Mayo, her doctor
52:01
Speaker 7: had this, you know, kind of crazy idea like let's
52:04
Speaker 7: take a fecal sample from her husband and transplant it
52:07
Speaker 7: into her and see if we can help this situation
52:10
Speaker 7: get better, And her symptoms improved. Within a day. She
52:14
Speaker 7: went from having had diarrhea every fifteen minutes and she
52:17
Speaker 7: was in a wheelchair and was like unlikely to survive
52:20
Speaker 7: to the next day her diarrhea was resolved.
52:23
Speaker 3: It's incredible.
52:24
Speaker 1: I think you're skipping over some of the crucial steps involved,
52:27
Speaker 1: Like when you talk about this fecal transplant, are we
52:29
Speaker 1: talking about the northern route the southern route, Like how
52:31
Speaker 1: do you get it from him into her?
52:33
Speaker 7: Yes, good question. You've heard me say my northern and
52:36
Speaker 7: southern route joke. Well, I mean your digestive tract is
52:40
Speaker 7: a tube, so you have a couple of entry points.
52:44
Speaker 1: She's so polite for me.
52:47
Speaker 7: And so to do a fecal transplant, you can take
52:50
Speaker 7: a healthy sample, put it in the blender and then
52:54
Speaker 7: get it into a nasal gastric tube down into your
52:58
Speaker 7: stomach from the northern route, or you can do it
53:01
Speaker 7: more like an enema into the bottom part of your
53:05
Speaker 7: digestive tract. You can also make capsules, and you would
53:09
Speaker 7: need to swallow about twenty or thirty glisterin capsules that
53:13
Speaker 7: have poop in them to have an impact, which reminds
53:16
Speaker 7: me of a favorite story. Stanley Falco at Stanford in
53:19
Speaker 7: the nineteen fifties was a hospital technician as a young man,
53:23
Speaker 7: he's now like he was one of the fathers of
53:25
Speaker 7: the hygiene hypothesis, But as a young man he was
53:27
Speaker 7: helping a surgeon who had this idea that they could
53:31
Speaker 7: hide healthy fecal samples from before a patient had surgery
53:35
Speaker 7: in their ice cream and they could eat that post
53:37
Speaker 7: operatively as they were waking up, because a lot of
53:39
Speaker 7: people were getting diarrhea from the antibiotics they were getting
53:42
Speaker 7: in the surgical ward, and without telling them, they had
53:46
Speaker 7: them eat ice cream with these fecal glisterin caps in there,
53:51
Speaker 7: and it was working great, like nobody was getting diarrhea.
53:54
Speaker 7: But when the director of the hospital found out, he
53:56
Speaker 7: fired them.
53:58
Speaker 1: Yeah yeah, no more Brownie Chunk ice cream.
54:03
Speaker 7: But they've all recovered and that thinking got them really far.
54:06
Speaker 7: So that was actually very ahead of their time to
54:08
Speaker 7: be doing that in the nineteen fifties. But then it
54:10
Speaker 7: was around twenty ten or so that this story in
54:13
Speaker 7: Minnesota I told you about emerged, and then since then
54:18
Speaker 7: it's become like really a sought after treatment for sea
54:21
Speaker 7: diff but very hard to regulate. It's kind of similar
54:24
Speaker 7: to blood donation, like we haven't figured out how to
54:26
Speaker 7: make synthetic blood and it's still a quest, and similarly
54:30
Speaker 7: for fecal material, it's a quest to figure out like
54:32
Speaker 7: what is even in there, which parts of it are
54:34
Speaker 7: needed to make a fecal transplant successful.
54:37
Speaker 1: So what's happening is that, like my microbiome is devastated,
54:40
Speaker 1: which is why I have Diarrhea'm getting somebody else's community
54:42
Speaker 1: that comes in and then grows into some healthy community.
54:45
Speaker 1: That's the idea.
54:47
Speaker 7: Well, that might have been initial thoughts on what the
54:49
Speaker 7: idea was, but interestingly in the last fifteen years, we've
54:53
Speaker 7: tried dissecting the poop into its various components, and so
54:57
Speaker 7: fascinatingly we've discovered that many of the components are enough
55:01
Speaker 7: to work as a fecal transplant. So you can filter
55:04
Speaker 7: the poop and only give the liquid supernatan, which has
55:07
Speaker 7: molecules and maybe viruses, but certainly not bacterial cells, and
55:11
Speaker 7: that's enough to cause a successful so called fecal transplant.
55:15
Speaker 7: We call it a filtered fecal transplant, and that still works.
55:19
Speaker 7: Or you can just isolate the spores out those are
55:23
Speaker 7: cells for sure, and give that as a treatment. That's
55:26
Speaker 7: the FDA approved treatment for the product v OUST, or
55:30
Speaker 7: you can take a whole fecal community. There's a Swedish
55:33
Speaker 7: poop from the nineteen nineties that has been cultivated anaerobically
55:37
Speaker 7: ever since then.
55:39
Speaker 6: Poop.
55:40
Speaker 7: Yes, and my students are like, hey, that poop is
55:42
Speaker 7: older than me.
55:46
Speaker 1: Whenever I use the bath though, I never imagine it's
55:48
Speaker 1: going to go down in history, but this one really did.
55:50
Speaker 7: Yeah, this one poop has saved like probably thousands of lives.
55:53
Speaker 7: This one poop has been cultivated anaerobically for many years,
55:57
Speaker 7: and so presumably none of the initial molecules from that
56:02
Speaker 7: poop are present, but just the progeny of all those
56:04
Speaker 7: generations of microbial growth, and that has been enough to
56:09
Speaker 7: cure seedff in many, many different people. So, to be honest,
56:13
Speaker 7: it's still a science question, like what you actually need
56:16
Speaker 7: to make a fecal transplant work. There also have been
56:19
Speaker 7: famous failures. There were phase three clinical trials of cocktails
56:24
Speaker 7: of microbes that people put together in the pharmaceutical industry
56:27
Speaker 7: thinking that that would work, and it didn't. So there's
56:30
Speaker 7: a geni sequax about the poop that just works perfect.
56:34
Speaker 3: So you mentioned that when you've got the liquid supernatan
56:37
Speaker 3: without any of the bacteria in it, but you've got
56:39
Speaker 3: their metabolic excretions plus viruses, it works fine.
56:44
Speaker 7: Yeah.
56:45
Speaker 3: Does that suggest it's the viruses that actually matter?
56:48
Speaker 7: What a cool question. I love that question. I don't
56:51
Speaker 7: know the answer, but it has been shown in like
56:53
Speaker 7: a number of different ways. There was a group in
56:55
Speaker 7: Germany and Kiel that showed this with the viruses with
56:59
Speaker 7: the filtered fecal filtrate. And then there's a group at
57:02
Speaker 7: the University of Copenhagen who have done really extensive studies
57:05
Speaker 7: in this really cool model of baby piglets, and their
57:08
Speaker 7: goal is to be able to help preterm infants in
57:11
Speaker 7: the NICKEU. And it's such a good idea because it
57:13
Speaker 7: would be very dangerous to give live microbes to pre
57:17
Speaker 7: term babies whose guts are in really bad shape. But
57:20
Speaker 7: if you could do it with the viruses, you might
57:22
Speaker 7: be able to create an environment that helps the gut
57:25
Speaker 7: microbiome develop successfully. And like babies in the nick you
57:29
Speaker 7: have really bad outcomes with their guts, like a third
57:32
Speaker 7: become septic, a third get necrotizing enterocolitis, and a third
57:35
Speaker 7: have what they call healthy outcomes, but I mean they're
57:38
Speaker 7: really in dire straits. And so I love what the
57:41
Speaker 7: group at the University of Copenhagen is doing because they're
57:43
Speaker 7: starting in a model of baby piglets, which is pretty
57:46
Speaker 7: similar to a human model, and I am optimistic that
57:49
Speaker 7: it won't take too long before they'll feel like it's
57:52
Speaker 7: safe to try it in babies because the room for
57:55
Speaker 7: improvement there is just enormous. So that to me is
57:57
Speaker 7: like a really really cool way that we could improve health.
58:01
Speaker 1: So if you get a transplant from somebody else they
58:03
Speaker 1: have a different microbiome, it's no guarantee that it's definitely
58:06
Speaker 1: going to work for you? Is the ideal transplant a
58:09
Speaker 1: donation from yourself, Like, if you're out there having good
58:12
Speaker 1: poops every day, should people put some of that in
58:14
Speaker 1: the freezer for the day when they have surgery or diarrhea.
58:18
Speaker 7: I really like that idea. It's certainly been a topic
58:20
Speaker 7: of conversation in our household.
58:23
Speaker 1: Don't dig around in our freezer unless you want some surprises.
58:26
Speaker 13: By the way, well, not your favorite part of our freezer,
58:29
Speaker 13: I know, but I appreciate your open mindedness. And by
58:34
Speaker 13: the way, when my students have to put vehicle samples
58:37
Speaker 13: in the freezer for our studies, we joke about like
58:39
Speaker 13: the right way to do that, and like, if your
58:41
Speaker 13: roommates don't like the idea, just empty out a box
58:44
Speaker 13: of strawberry popsicles or like chicken nuggets and you could
58:46
Speaker 13: just hide your samples in there. And if they're trying
58:48
Speaker 13: to steal a popsicle, I mean, that's on them.
58:52
Speaker 1: Oh they're going to get a popsicle. It's not going
58:54
Speaker 1: to be strawberry exactly.
58:56
Speaker 3: After this conversation, I'm never going to look at popsicles
58:59
Speaker 3: again say yeah.
59:03
Speaker 7: Yeah, So the question was could we do like auto
59:07
Speaker 7: like self fecal transplants and have that work. And that
59:09
Speaker 7: has been studied in a lot of different contexts also,
59:12
Speaker 7: for like recovery from antibiotics. If you really know that
59:15
Speaker 7: you're healthy, Like maybe everybody should be banking their own
59:19
Speaker 7: sample at some point in their life when they just
59:21
Speaker 7: were digesting really well and they were eighteen and had
59:24
Speaker 7: like been eating really well for the summer or something,
59:26
Speaker 7: save a moment of that glorious part of your health
59:29
Speaker 7: in the freezer so you could restore yourself to it.
59:32
Speaker 7: I like that idea. I've proposed this for different kinds
59:35
Speaker 7: of context. Like one time I wrote a proposal about
59:38
Speaker 7: helping people who are going to have to have radiotherapy
59:41
Speaker 7: for cancer. And often people get essentially diarrhea and other
59:46
Speaker 7: really rough consequences of the radiation treatment. So the idea
59:50
Speaker 7: was to restore their health to what they were before
59:52
Speaker 7: the treatment. But somebody who has cancer might have cancer
59:56
Speaker 7: promoting properties in their own fecal microbiomes, so you could
1:00:00
Speaker 7: certainly bring them back to getting cancer again. I mean
1:00:04
Speaker 7: this has been studied extensively, Like this kind of approach
1:00:07
Speaker 7: has been used. There was a big study in New
1:00:09
Speaker 7: York City of people who were getting bone marrow transplants
1:00:13
Speaker 7: for blood cancers, where they did transplants from people's before
1:00:18
Speaker 7: fecal sample in order to try to help them avoid
1:00:21
Speaker 7: getting I mean, people get terrible infections after getting cancer treatment.
1:00:25
Speaker 7: So this is an area again kind of like the
1:00:27
Speaker 7: preacher and babies. There's like a ton of room for
1:00:29
Speaker 7: improvement there. But the concern is that you would cause
1:00:32
Speaker 7: cancer again, so maybe a healthy donor is safer. And
1:00:36
Speaker 7: then I hear your question, well, what if the healthy
1:00:38
Speaker 7: donor is really different than you. Well, another thing that
1:00:40
Speaker 7: happens is it's rare that we follow up our studies
1:00:43
Speaker 7: long enough to really see what happens. But there was
1:00:46
Speaker 7: one study of autistic children where they did fecal transplants
1:00:49
Speaker 7: from a stranger, like a healthy donor, not a family member.
1:00:52
Speaker 7: But then they followed up for two years both the
1:00:55
Speaker 7: kids with autism and a healthy sibling in the same household.
1:00:59
Speaker 7: And I loved that they did this for two years.
1:01:02
Speaker 7: This is Rosy Krasmo like Brown at Arizona, and they
1:01:07
Speaker 7: found that at first the autistic children who received the
1:01:11
Speaker 7: fecal transplant from a stranger donor their guts were more
1:01:15
Speaker 7: similar to the healthy donor, but after two years their
1:01:19
Speaker 7: gut microbiomes resembled their siblings more, but they did have
1:01:23
Speaker 7: higher diversity. So it's almost like the fecal transplant kick
1:01:26
Speaker 7: started the capacity to carry a higher microbial diversity, But
1:01:31
Speaker 7: then all those strains got replaced by strains that were
1:01:35
Speaker 7: available in the household. So the household influence is really important,
1:01:40
Speaker 7: and it makes me wonder like when people get married,
1:01:43
Speaker 7: there's going to be a battle of the microbiotas and
1:01:45
Speaker 7: somebody's going to win, and that hasn't really been studied
1:01:48
Speaker 7: that much.
1:01:48
Speaker 1: You know, killed diarrhea do us part? Can we talk
1:01:53
Speaker 1: about the probiotic industry you mentioned earlier. It's eighty billion
1:01:57
Speaker 1: dollars and I feel like I see pills and powders
1:01:59
Speaker 1: and yogurts promoting probiotic this and probiotic that. What's in
1:02:04
Speaker 1: those And what's your take on whether they're likely to
1:02:07
Speaker 1: do anything?
1:02:08
Speaker 7: Well, that's a really big question. It is a really
1:02:10
Speaker 7: big industry. I was even just comparing the size of
1:02:13
Speaker 7: the probiotic industry in the antibiotic industry, and I think
1:02:16
Speaker 7: the probiotic industry might even be a bigger money maker
1:02:20
Speaker 7: than antibiotics, but it's close. But I mean that's amazing
1:02:23
Speaker 7: to me. Eighty billion dollars, like that's close to the
1:02:26
Speaker 7: GDP of many nations. And so whether it could work
1:02:30
Speaker 7: is one question. And yes, the idea of a probiotic
1:02:34
Speaker 7: makes sense. I mean, if you could get the right
1:02:36
Speaker 7: bug to the right place at the right time, that's
1:02:38
Speaker 7: a great idea. It could definitely work. When we say probiotic,
1:02:42
Speaker 7: that includes fermented foods like yogurt and kombucha and kiefer
1:02:46
Speaker 7: and miso, and those we actually can see really kickstart
1:02:51
Speaker 7: diversity in our guts. Not necessarily because the bacteria in
1:02:54
Speaker 7: those products are colonizing our gut, but they can kickstart
1:02:58
Speaker 7: diversity in a good way. Most people when they take
1:03:02
Speaker 7: a probiotic, and many packages claim that it's gonna directly
1:03:06
Speaker 7: increase your microbiome diversity. I think a lot of people
1:03:09
Speaker 7: when they eat a probiotic, imagine that now that bug
1:03:12
Speaker 7: is happily living in their gut and they just like
1:03:14
Speaker 7: got their community a little happier now. Most probiotics actually
1:03:18
Speaker 7: don't do that. Most are transient. So if you are
1:03:21
Speaker 7: taking those pills and then you measure people for a week,
1:03:24
Speaker 7: you'll see a wash out period and after a week
1:03:26
Speaker 7: or so it'll be gone, which is probably not what
1:03:29
Speaker 7: people imagine. You also might not want the probiotic to stick,
1:03:33
Speaker 7: so I always remember the story of a startup in
1:03:35
Speaker 7: San Francisco where they evolved probiotics that were good at
1:03:39
Speaker 7: binding to mucus, with the idea that they could persist
1:03:42
Speaker 7: in the gut. But they forgot about gum mucus and
1:03:44
Speaker 7: everybody got cavities in their little study.
1:03:49
Speaker 3: I'm not laugh is so complicated, I know.
1:03:55
Speaker 7: So on average probiotic packages, you know, they don't have
1:03:59
Speaker 7: to have evident for the claims they make on the packages,
1:04:02
Speaker 7: so they can say some pretty fantastical things. And actually,
1:04:06
Speaker 7: in my Microbiomes class this quarter, we had a probiotic
1:04:10
Speaker 7: sus score, like a suspicion score activity where everybody had
1:04:14
Speaker 7: to go find a probiotic with crazy claims on the
1:04:16
Speaker 7: package and then try to investigate the claims and like
1:04:18
Speaker 7: what evidence there was for them, and there was not
1:04:21
Speaker 7: usually a whole lot of evidence, And the students had
1:04:24
Speaker 7: amazing comments afterwards that were like, man, if I saw
1:04:27
Speaker 7: a celebrity claiming that a probiotic worked, I just would
1:04:30
Speaker 7: believe it. It never occurred to me to like investigate the evidence.
1:04:32
Speaker 7: And I'm like, you guys are science students. I'm glad
1:04:35
Speaker 7: if you're learning that.
1:04:36
Speaker 3: Yeah, it's important.
1:04:38
Speaker 7: Yeah. So you know, just off the top of my head,
1:04:41
Speaker 7: you know, there's probiotics out there that are named like
1:04:44
Speaker 7: happy hoo ha, and they claim to improve your imaginal
1:04:47
Speaker 7: micro or like you know, anyway, there's some pretty funny ones.
1:04:54
Speaker 7: But there are some probiotics that are well investigated and
1:04:57
Speaker 7: people are doing studies with them, and so sometimes they're
1:05:00
Speaker 7: not sharing the evidence in order to protect their ip.
1:05:04
Speaker 7: So it's complicated. But the way the industry is regulated
1:05:07
Speaker 7: is just that the probiotics have to be generally regarded
1:05:11
Speaker 7: as safe or grass, which is not a very high standard.
1:05:14
Speaker 7: I mean, it's a high standard in the sense that
1:05:16
Speaker 7: like this thing's not going to kill you, that's.
1:05:17
Speaker 3: Good, might give you cavities, might give.
1:05:20
Speaker 7: You cavities, or might just do absolutely nothing. And I
1:05:22
Speaker 7: mean the supplement industry, even beyond probiotics, is an enormous
1:05:26
Speaker 7: industry and there's very few claims and it's pretty hard
1:05:30
Speaker 7: to know. I mean, even for you know ourselves, like
1:05:33
Speaker 7: Daniel and I we have a son who's an athlete,
1:05:35
Speaker 7: and he's always, you know, really willing to do what
1:05:38
Speaker 7: it takes to be healthy. And so we've had a
1:05:40
Speaker 7: lot of conversations about what we understand about what's in
1:05:43
Speaker 7: a supplement versus what we understand about what's in a food.
1:05:46
Speaker 7: And you know, with the tools we have in our
1:05:48
Speaker 7: own households, we can't really assess the safety of food
1:05:52
Speaker 7: or supplements. That's why we need infrastructure and institutions that
1:05:57
Speaker 7: help us understand that. But a lot of the things
1:05:59
Speaker 7: that we can buy in packages might have stuff that's
1:06:03
Speaker 7: dangerous in them, and we have to be really careful.
1:06:05
Speaker 7: So my general instinct is to lean towards food, and
1:06:11
Speaker 7: you know the advice to generally not eat things that
1:06:14
Speaker 7: your grandparents wouldn't recognize as food, or maybe it has
1:06:16
Speaker 7: to be our great grandparents now, because a lot of
1:06:19
Speaker 7: the processed foods that are available to us these days,
1:06:23
Speaker 7: with tons of ingredients we can't even pronounce, it could
1:06:27
Speaker 7: be really damaging our health. It's not like I have
1:06:30
Speaker 7: really great evidence for every single one, but I think
1:06:32
Speaker 7: that leaning towards eating things that you can recognize tends
1:06:37
Speaker 7: to work the best for the evidence that we have
1:06:39
Speaker 7: right now.
1:06:40
Speaker 1: And earlier on you mentioned fiber and beans. Why is
1:06:43
Speaker 1: fiber something good to eat? I mean, if you're not
1:06:45
Speaker 1: going to do a poop transplant and you're not buying
1:06:47
Speaker 1: happy hooha or whatever, if you're just going to try
1:06:49
Speaker 1: to do this through like healthy eating and food, tell
1:06:52
Speaker 1: us why fiber is important.
1:06:54
Speaker 7: Definitely. So, fiber is the part of carbohydrates that doesn't
1:06:58
Speaker 7: get digested very quickly. It's longer chains of carbohydrates that
1:07:02
Speaker 7: your human enzymes can't even access. So the way to
1:07:05
Speaker 7: figure this out is if you look at a nutrition label,
1:07:07
Speaker 7: it'll list the total carbs and then it'll list the
1:07:10
Speaker 7: subset of the carbs that are fiber. So for a
1:07:12
Speaker 7: piece of white bread, it might be like nineteen grams
1:07:15
Speaker 7: of carbs one gram of fiber. Wheat bread might be
1:07:18
Speaker 7: nineteen grams of carbs five grams of fiber. Okay, cool.
1:07:21
Speaker 7: So now we're talking like you know, nearly a quarter
1:07:24
Speaker 7: of the carbs in that piece of bread is fiber.
1:07:26
Speaker 7: It's going to be slower to hit your blood sugar levels.
1:07:30
Speaker 7: It's going to persist in your digestive track down to
1:07:32
Speaker 7: your colon where all the microbes live and give them
1:07:35
Speaker 7: some food. So that's pretty good. Now let's talk about
1:07:37
Speaker 7: beans and lentils. Half of the carbs in beans and
1:07:40
Speaker 7: lentils are in the form of fiber. So if you
1:07:43
Speaker 7: eat a cup of black beans or old navy beans
1:07:46
Speaker 7: or lentils in a day, you'll get probably ten or
1:07:49
Speaker 7: twenty grams of fiber out of the thirty or forty
1:07:52
Speaker 7: grams of carbs. That's half of your fiber needs for
1:07:55
Speaker 7: the day. So the daily recommended allowance of fiber in
1:07:58
Speaker 7: the US is twenty five to three five grams per day,
1:08:02
Speaker 7: and we're usually getting half of that. Most Americans are
1:08:04
Speaker 7: getting ten to fifteen grams per day, So we all
1:08:07
Speaker 7: need to think about how to fill our fiber gap.
1:08:09
Speaker 7: You always hear about how we're not eating enough protein.
1:08:11
Speaker 7: I mean, to be honest, we're probably eating money of
1:08:12
Speaker 7: protein in the United States, but we really are not
1:08:14
Speaker 7: eating enough fiber. If you eat fiber, you are fueling
1:08:18
Speaker 7: the microbes in your colon. And then if you do
1:08:21
Speaker 7: experience some kind of stress, whether it's antibiotics or diarrhea
1:08:25
Speaker 7: or just like literally stress that causes inflammation and oxygen
1:08:29
Speaker 7: descending upon you and making it harder for those bugs
1:08:32
Speaker 7: to thrive in your colon. When you have fiber in there,
1:08:35
Speaker 7: you've given the bugs a place to hide out, so
1:08:37
Speaker 7: you can weather the storms of any kind of other
1:08:40
Speaker 7: fluctuations in your life better and keep the microbes happier.
1:08:43
Speaker 7: So like, if you did know you had to take antibiotics,
1:08:46
Speaker 7: I would definitely really recommend making sure you're eating enough
1:08:50
Speaker 7: fiber and fermented foods actually are another really good contributor.
1:08:54
Speaker 1: All right. So that's scientific evidence that chili should have
1:08:57
Speaker 1: beans in it. Settled that age old question.
1:09:01
Speaker 7: I mean, I don't think there's anyone who would disagree
1:09:04
Speaker 7: that if you wanted to protect your microbiome, having beans
1:09:08
Speaker 7: in your chili would be a good idea.
1:09:10
Speaker 3: All right, everybody, So tonight, grab your beans and your
1:09:13
Speaker 3: bino and hopefully Katrina Whitson will be back on the
1:09:16
Speaker 3: show and not too long. Thanks for spending some time
1:09:18
Speaker 3: with us today.
1:09:19
Speaker 7: Awesome. Thank you.
1:09:27
Speaker 3: Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We
1:09:31
Speaker 3: would love to hear from you, We really would.
1:09:33
Speaker 1: We want to know what questions do you have about
1:09:36
Speaker 1: this Extraordinary Universe.
1:09:38
Speaker 3: We want to know your thoughts on recent shows, suggestions
1:09:41
Speaker 3: for future shows. If you contact us, we will get
1:09:44
Speaker 3: back to you.
1:09:45
Speaker 1: We really mean it. We answer every message. Email us
1:09:48
Speaker 1: at Questions at Danielankelly.
1:09:51
Speaker 3: Dot org, or you can find us on social media.
1:09:53
Speaker 3: We have accounts on x, Instagram, Blue Sky and on
1:09:57
Speaker 3: all of those platforms. You can find us at d
1:09:59
Speaker 3: and Hey, universe
1:10:01
Speaker 1: Don't be shy write to us.