Katie Amato wonders what it means to be human (she's a biological anthropologist)

the typical Western diet of more meats, less fiber, processed sugar and things like that. What kind of overall effect is that having on our microbiome? Bad.

You don't need science to tell you that.

Hi, I'm Rachel Moeller-Gorman. I'm a science writer and I interview scientists about their research. But I've always wanted to pry a little deeper and ask more personal questions like, what were you like as a kid? What happens when you make mistakes? Why should the rest of us care about your research? I can't wait to ask these questions and many more on Socializing with Scientists. Hey everyone, welcome. Today my guest is Katie Amato. Katie is a scientist at Northwestern University in Chicago, and I discovered her initially because I read some of her research on how drinking juice versus eating fruit affects the tiny industrious microbes in our guts. But then I looked her up and found out that she does so much more. She also followed animals all around the rainforest for her research, but she did it to figure out how humans evolved and whether the Thank you so much for joining us. But basically, as she says, she's just trying to figure out what it means to be human, like we all are, I guess. So anyway, here we go with Katie Amato. So welcome. I'm so happy to have you here today. And the first question I always ask is, what kind of scientist are you? And then what does that mean? That's a great question because I sometimes am not sure exactly how to label myself. Technically, right now, I'm a biological anthropologist because I'm in the Department of Anthropology. A biological anthropologist is somebody who tries to understand what it means to be human from a biological perspective. So understanding how aspects of our health and how our bodies work have changed over evolutionary time, but also thinking about variation across the world today in different populations And a lot of what we're interested in is understanding how environments have contributed to that sort of variation in how our bodies work. I could also be considered a primatologist, a microbiologist, an ecologist. So I can put on a lot of different hats depending on who I'm talking to and what the problem is. You do it all. So you then, you study the gut microbiome, right? Like is that one way that you get at some of those things you were just talking about is by looking at... Correct. Yes. So I study the microbes that live in and on our bodies and how they affect how our bodies work. And I do that in non-human primates in the wild, trying to understand how their bodies are responding to their environments and how the microbes might be mediating those sorts of interactions. And then I also try to understand how that translates into what's happening in humans. So looking at humans and variation in their environments and how that affects their their microbes and then how those microbes feed back to affect health across human populations, but also trying to compare humans and other primates to understand how we might or might not be similar to other primates and then trying to figure out how that might help us understand human health better as well. Okay. So I wanted to kind of establish the basics first. I know a lot of people have heard of the gut microbiome and they have kind of a general sense of what it is, but can you sort of, I guess, walk me through first, what do you consider the gut like what parts of the body are the gut and then how do bacteria get in there like what are these bacteria just sort of like a basic primer on what what is going on in there absolutely it's Complex, but really fascinating. So when I refer to the gut, really, that means the whole digestive tract. So going from the stomach to the small intestine to the large intestine, the majority of microbes that live in our digestive tract are in the large intestine. When I say microbes, I'm referring really, that's a fancy term for just anything you need a microscope to look at. So that includes bacteria, this kingdom called archaea that we just discovered a few decades ago, viruses and microscopic eukaryotes. So things like parasites, you think of like an amoeba like that. The majority of the microbes that are studied today that we know the most about are bacteria. So usually when I'm talking about microbes, I mean bacteria, but technically the term means a lot more. In the gut, there are bacteria and other microbes in the stomach, in the small intestine, in the large intestine, but really the majority are in the large intestine. That is the place where a lot of what is left over from what we eat that we can't digest ourselves ends up, and the bacteria are really able to use it there. And so our body kind of has to control where these microbes are to some extent, right? If you think about your immune system. Its job is to keep things out of you that are not you. And we have all these microbes in and on us that are not us. And so our immune systems have developed over evolution to kind of figure out who's there and whether they're okay to stay or not. And so it does a kind of stronger job of that in the small intestine because that's where we're absorbing a lot of our nutrients. And we don't want other microbes taking that away from us, right? But once we get to the large intestine, we've gotten a lot of that sugar, that protein, all that out of our diet. And a lot of what's left are things that we can't digest, things like fiber, things that have been bound to plant toxins. So things like tannins. Tannins tend to be in like red wine and coffee. It's that feeling in your mouth, the kind of like... dry feeling you get when you drink those things those are tannins they're binding the proteins in your mouth and so they bind the proteins in your food and so you don't digest that as easily that's the sort of thing that gets to the large intestine and then bacteria can actually process that and use that as energy so they really like to hang out in the large intestine they get a benefit from being there how do we get these microbes is a great question um And I guess I'll take one quick step back and say we have microbes in other places beyond the gut, right? They're in their mouth, they're on our skin, etc. We kind of know the most about the ones that live in our gut. But even then, I would say that with the caveat that this is a pretty new field, we only really were able to start understanding which kinds of microbes are in and on our bodies and what they're doing. around the turn of the century, around the 2000s. So it's a very young field and there's a lot we don't know, but we know the most about the gut. In the gut and the rest of the body, we generally in utero think that there are not a whole lot of microbes there. We used to think it was sterile. I think we're careful about saying anything is sterile anymore. There's a lot of debate about whether there's microbes in utero. If there are, there's very few. And really, we get this kind of input of microbes at birth. So that's when babies are exposed to microbes in mom's vaginal tract, fecal microbes, skin to skin gives exposure to babies from the skin microbiome. Breast milk, we now know has microbes in it, specific microbes that we consider to be probiotic. And breast milk also has sugars in it that only microbes can digest, the baby itself cannot. And so all of that comes together to start to kind of see the microbiome in babies and then we start to get other inputs from the environment as we get older right crawling around putting things in our mouths coming into contact people and pets and things like that so it really is this development that happens very early in life

Okay.

And you mentioned that they digest certain types of food for us then. How does that work? And are we totally unable to process those foods without the bacteria? Yes. So there are things that we can digest that bacteria can digest. They would be super happy to. digesting simple sugars, right? That's like metabolically easy for them. That's an easy thing for them to do. But they can do things that we can't do at all. So we do not have the enzymes, the chemicals in our body to digest fiber. We eat a big salad full of kale. We can't actually process a lot of that. But microbes can. They do it through this process called fermentation in the gut because there's not a lot of oxygen in the gut. And they can go through this fermentation of the fiber and break it down. And by doing that, they get energy for themselves from kind of something that we're discarding from our diet, right? But when they do that, they also are producing things that we can then use that we couldn't otherwise. So they produce something called short-chain fatty acids when they do this fermentation of fiber. And these short-chain fatty acids are energy sources that we can absorb from our large intestine, and we can use them. There's different types of short-chain fatty acids, and some are present preferentially used by different parts of the body. So like the gut likes a certain type of short chain fatty acid that it uses for energy. Skeletal muscle likes a different kind. These short chain fatty acids we're also discovering are fascinating. They can do all sorts of things in the body. So they have anti-inflammatory properties. They can affect gene expression. We think they can maybe cross the blood brain barrier and provide energy directly to the brain and or change how genes and things are working in the brain. They can signal other parts of the body to switch metabolism from fat burning to fat storing or vice versa. So they're doing a lot of things in the body that I think we are understanding more every day, but we really started like 20 years ago with, oh, this is just energy. And now we realize that they're doing all sorts of other things to influence how our body works. I guess the other thing that's worth noting is that these microbes, that's one of the main things that these microbes do is digest fiber for us and produce all these compounds. But they're producing things besides short chain fatty acids and they can digest other things besides fiber. So there's a lot of other interesting pathways where these microbes are interacting with our bodies. So a lot of our serotonin originates in the gut. a lot of dopamine. I think it's something like 50% of dopamine comes from the gut. GABA, another neurotransmitter that can affect our behavior, some of that is produced in the gut. These gut microbes affect how bile acids are kind of recycled in the body. And bile acids are something that we use to digest the fats in our diet, right? They're produced by the gallbladder and interact with the liver. And the way that microbes interact with the bile acids that get into the large and after the liver puts, sorry, the gallbladder puts things into the small intestine can affect how our body works. So there's a really interesting study where they found that the types of microbes you have can actually interact with the diet if you're eating a lot of red meat and produce this compound that contributes to atherosclerosis disease. So there's all these sorts of fascinating connections with what we're eating and how the microbes are processing that and then what they do create and how that then feeds back to affect our body so is it that when we hear about i don't know the microbiome being dysregulated or people being on antibiotics or whatever is it that we don't have the right kind of percentages of the right kind of bacteria in there that are producing enough say dopamine or serotonin or whatever and things get kind of messed up like is there an ideal percentage of certain types of these bacteria that allow our body to function properly Yeah, I think that's the million dollar question in the field, right? That's what everybody wants to figure out. And presumably, yes, there is some ideal percentage of these different microbes. It gets really tricky because you have to think about what aspect of health are you thinking about? We know that these microbes, I've talked about how they can affect digestion and the sorts of things we absorb from our food, right? These neurotransmitters can affect the brain and behavior there. These microbes can also feed back since the immune system is basically communicating with them to allow them to be there. These microbes are communicating back. And so there's also studies that have shown that these studies that have shown that these studies that have shown that these microbes actually program our immune microbes actually program our immune microbes actually program our immune system and help it operate right make sure system and help it operate right make sure system and help it operate right make sure that it's not becoming overly reactive and contributing to things like allergies, but also making sure it is reacting when there's an infection, right? So these microbes can really affect all aspects of our health. And so the question becomes, are you talking about mental health? Are you talking about metabolic health? Are you talking about your immune system and how it's functioning? And it's probably not the same microbes necessarily that are contributing to those functions. And so I think there is very likely to be a range of kind of correct percentages of different types of microbes that you need to be healthy. And again, you don't wanna put so much effort into maybe promoting certain types of microbes that affect one aspect of health. And then there's this negative trade-off for another aspect of health. That's something we're still trying to figure out, I think. And we kind of haven't come up with the magic formula. But yes, when we talk about a dysbiotic gut, the idea is that There's this kind of balance of microbes that are ideally allowing all these different aspects of our body to be kind of regulated and functioning the right way. And you have a shift kind of out of that balance that can lead to some aspect of the body not working the way we want it to, right, and health issues. And is there a way, this might not be exactly your area of expertise, but a way to live your life in such a way just to encourage these helpful types of bacteria, like food you can eat or... exercise or i don't know where you're living the environment gardening like i don't know are there certain things that healthy people do that have these healthy microbiomes? Yes, I think all of the things you just mentioned. I sometimes laugh and say it's this brand new cutting edge field and it's teaching us the lessons we all kind of already know. So, you know, I think there's a lot of people trying to figure out what are these specific super foods, right? I can tell you to go eat like this many blueberries and this half a cup of chia seeds. And I think we'll get there eventually. I What we do know is that eating fiber is a good thing. It allows those microbes to produce those short-chain fatty acids, which are good for almost any aspect of health we can look at. When microbes don't have fiber, they tend to go for other things to support themselves. They'll break down leftover protein in our diet, or they'll even go on the mucus lining of the large intestine will start to kind of eat away at that a little bit. And that can cause health problems in and of itself. And then also the things they're producing as a byproduct don't have the same health benefits, right? So a lot of fiber fermented foods, are really great. Um, they have the microbes in them themselves. So they're a probiotic. Um, they have their prebiotic. So prebiotic is food for microbes and things like fiber. Right. Um, and then they have a lot of the things these microbes produce in them because the microbes were living in the food as part of the production. So they have things like short chain, fatty acids and other compounds that microbes produce. Um, So some of the kind of exploration I've done in the literature suggests that evolutionarily eating fermented foods has been really a big part of our diet as humans. And I think it's really important for supporting these microbial communities. In terms of other aspects of life, yeah, I mean, the people you're around transfer microbes to you. So choose wisely. No, I'm kidding. But we just know that there's types of microbes that we get from other people that we wouldn't get if we were more in isolation and we can kind of, you know, you think about disease and passing disease among people, which is a health risk, but we're also passing these good microbes with each other. Yeah. There's some cool work that suggests that if we weren't kind of social, there's some types of microbes that we wouldn't be able to kind of support because they kind of get washed out of the body quickly. And so they need to be able to kind of hop from person to person. So having that social interaction is a good thing. Yeah. Being outside the microbes that are in the spaces that we live in inside tend to come from us. Right. We're like microbes. And so it's the microbes that are coming from the people in the buildings. It's microbes that can live on the materials inside. Right. So things that are going to live on, you know, I'm looking at a lot of wood furniture in my house right now, but I'm thinking about like offices where it's like a lot of like, you know plastic and

metal

and if we're outside uh we get microbes from the soil and from plants and you know from what's outside and we think that tends to have a benefit as well there's a cool study that showed that with some kids in a daycare and that exposure to being outside actually exposed them to more of these good microbes and led to reduced inflammation so yes Get outside, eat fiber and fermented foods. Don't over sanitize, right? Again, thinking about that, like using hand sanitizer and antibacterial soap and, you know, using all these antimicrobial disinfectants, like on our kitchen surfaces and things like that. We want to do that, right? So that we don't have like salmonella growing in the kitchen, but we also don't want to do it if we don't need to because we're killing off the good microbes when we do that.

So you study evolution as well.

How would understanding the gut microbiome help you understand evolution that are where we came from? So what's really interesting about these microbes from this evolutionary perspective There's just a lot of environmental input in the types of microbes that you get. So it's something that can change relatively quickly in terms of what a person's body has. So it's not like genetics where it's passed from parents to offspring in a pretty robust way, right? It is, but there's kind of more noise involved, which allows kind of more variation across generations. And it allows for change to happen more quickly than it happens with our genetics. And what's Interesting, and why I'm comparing this to genetics is that these microbes, as I've kind of been alluding to, really affect how our bodies work, right? They're going to affect kind of how we live in the world, and we know that that's what selection acts on, right? So when we think about kind of survival of the fittest, you have a group of organisms, and some of them have one trait and others have another and whichever trait kind of works best in that environment, those individuals that have that are going to reproduce and that's going to be passed on across generations. And we tend to think about that as our DNA, right? But these microbes can actually affect those traits as well. And they can be passed on across generations, but again, not in a way that's quite so faithful from one generation to the next. So there's room for more noise and potentially room for kind of quicker adaptation as a result of these kind of microbes that one would pick up. So I'm trying to think of a good example here without getting too far into the weeds. I mean, I think diet is a good example in that, again, these microbes can kind of dictate what we can digest. And if we're thinking about like some of the wild primates that I study, some of them consume a lot of leaves, which is really hard to digest, right? Primates like us don't have the enzymes, the chemicals to digest this fiber that's in these leaves, right? So they need microbes to do it. And you can imagine across evolutionary time, if... food availability starts to change in an environment, right? Maybe there's less fruit, which is easier to digest. You don't necessarily need microbes to do that. If that starts to disappear and a primate starts to have to depend more on things like leaves because they're around, That's gonna be hard for the primate to kind of change their physiology through genetics to be able to do that, right? That's gonna take a really long time, multiple, multiple generations. But you might be able to pick up some microbes that are better at doing that, right? And that could actually speed up that process so that that species could start to eat this new food without having to completely change the way its gut works and the way the rest of the body works. The microbes can kind of pick up the slack, if you will. And so then that species might start to eat more leaves over time. And then maybe the genetics catch up, right? And there is some sort of change in how the gut works based on kind of the physiology and animals born with. I think of it as this kind of stepwise process potentially. So these microbes essentially can kind of help, I think, guide the direction of how species are changing over time, essentially. How do you study that? How do you study what microbes were in, say, ancient people? Or I guess you study primates then, too, and look in their guts? Yeah, so there's kind of three ways people go about this. One is to compare humans to our closest living relatives, which are other primates, and we kind of look for what's shared and what's not shared. And the things that are shared are probably things that a common ancestor had, right? And so we can think about going back in evolutionary time and saying, okay, if all these primates have this, our common ancestor probably had this, which means it's probably ancient to humans as well. I also like, as I was saying, to use primates in terms of thinking about Okay, if we're in this habitat, which humans don't live in anymore, right? If we're in a woodland savanna habitat, my population of humans that I live in is not living in that habitat. But maybe I can go study primates that are in that habitat and understand how their microbes are responding to the sorts of challenges that environment puts forward. We can also do that with some populations of humans that maybe are living in those savanna woodland habitats currently, right? We have to be really careful because just because a population of humans today is living in that savanna grassland doesn't mean they're ancient. They're clearly modern people with modern practices. But again, there might be aspects of their lifestyles that we think might be more similar to some of our ancestors. And we can look at kind of the interaction between those aspects of lifestyle and the microbes and health. The last thing that people like to do is look at coprolites. So that's fossilized poop. So you can actually go out and find fossilized poop. It's not easy. I've never done it myself. But you can imagine that poop tends to not hang around so long in the environment. So it's not something we find at archaeological sites super often. But when it is found, we can try to go and look at the microbes that are in those fossils as well. There's caveats with that as well, like there are with the primates and the modern human comparisons in that those samples have been sitting out for thousands and thousands of years, right? And so depending on how the poop was preserved, right, it could be more like what it was when it came out of the person, or it could be more like, you know, the dirt that it's sitting on. And so there's kind of a lot of risk there in terms of what microbes are really still there. And then what we're using to measure these microbes, which I guess I haven't said yet, is DNA. We're sequencing the DNA of these microbes and identifying what they are using that technique. And DNA only lasts so long. So if I find a coprolite that was like hundreds of thousands of years old, the DNA would not be good anymore. So there's a limit to how far back we can actually go with this method. But yeah, those are the three primates comparisons to other human populations and coprolites. Yeah. I was going to say, how is that even preserved over like what, what would do to keep poop preserved for that long? We tend to find them in like deserty areas more where things dry out really quick. But yeah, it's pretty rare to find coprolites. I think there's, you know, a couple of papers out there and there's a handful of coprolates in those papers total, you know, less than 10 or 20 in those papers. So we're always eating for more, but there's not that many out there.

Well, on that note, I'm going to shift gears here

and move the focus over to you a little bit more. Where did you grow up? Did you grow up in the city? Do you grow up in the country? Did you, you know, experience being outside and, you know, increasing your gut microbiome by frolicking in the forest. I don't know. What was your childhood like? Yes and no. So I grew up in the suburbs of Chicago. And so I wasn't right in the city, but definitely not the country either. You know, without traffic, it's like a 30 minute drive downtown. But there was a lot of just kind of backyard time that I had. So we didn't do like a lot of camping or hiking and things like that. But I was one of those kids that was like, you know, told to go outside and play and come back when it was dark. And a lot of running around the neighborhood, bike rides and kick the can and go to the graveyard. We would go to like... You know, the botanic gardens and nature preserves and things to walk around. I think my mom always encouraged us to kind of observe and learn from what was around us, not in a specific like pay attention to nature way, but just kind of more generally and then encourage us to generally be outside. Um, I remember my younger brother and I remember at one point, I don't know how old we were. I must've been like eight and he was five or something. And I was like, we're going to spend the whole day outside in the backyard. And I like brought snacks. And I remember him like, well, what if we have to go to the bathroom? Well, you can go inside really fast and then you have to come back out again. I had this whole plan. So, um, I think I went with it maybe more than, um, More than I was directed to, right? I enjoyed it. I remember one of my favorite books was the Boxcar Children. Oh, those are mine too. I love those books. So I think that's what I was trying to recreate. I was like, we're going to live in the backyard in this little house that we made. We're going to, you know, find plates that we're going to make. Yeah, no parents. No parents. Take care of yourself. We're going to survive in the forest. in the backyard of the suburbs of Chicago so so yeah I wasn't like out in the wild but I was trying to be but you had freedom and you kind of did your own thing yes Was there some favorite thing that you did in the summer? It's just summer here now, and I'm thinking about all the fun summer things I did as a kid. Is there something in particular that you loved to do in the summer as a kid? We would do a lot of bike rides. My mom would take us on a lot of bike rides, or both my parents when it was the weekends. We'd go to the beach a lot. Oh, Lake Michigan? Yeah, Lake Michigan, yep. Yeah, it really was just kind of a lot of spending time outside, honestly. So nothing in terms of like... formal organized experiences but just kind of enjoying being outside yeah so do you think that kind of informed your love of science or when did you was there a moment when you first thought oh I like I like science I like kind of experimenting or trying to solve problems answer questions yeah I think that came somewhat naturally I think it came from that kind of exploring and being outside I know my grandmother used to say she'd watch me I'd be like two, three years old and I'd be squatting over in like the patio watching the ants and trying to figure out what they were doing. So I think that always was kind of part of my interests. I do always credit the interest in primates to a second grade unit we did on Jane Goodall. We learned about her and I thought that was fascinating. We made these little clay chimpanzees. I still have mine. And I was like, oh, again, it was like the go live in the forest kind of thing, you know, And I was like, that would be amazing. I never thought I was going to do anything like that because, like, who does that? I didn't know anybody that was a scientist, right? I didn't know anybody that did anything like that. But I thought it sounded really interesting. Yeah. Yeah. And I always did. I was really good at math. I really liked to try to figure things out. So I kind of just kept taking that path as I grew up. I had some fantastic biology teachers in high school, John and Jim Burnside, they're brothers. And one of them taught kind of intro bio and the other taught AP bio when I was a senior. And they were so enthusiastic and engaging and, you know, treated us as equals. But we're excited about the And so, you know, I already had the interest, but that really kind of blew it open for me. And I was like, oh, I like biology. I'm really going to do this. You know, teachers are so important. Like I said, I was really good at math, but I had terrible physics teacher. So I decided very quickly I was not going to do physics, which I probably actually could have done. But again, it was the teachers. Right. And I kind of just kept following that pathway. I had the opportunity. to do a marine biology program at the Shedd Aquarium as a high schooler in Chicago. I think they still do it. You go to classes for two or three weeks, and then they bring you down to the Bahamas on a research assignment for a week. It was really cool, and you do little science projects, and then you come back and do a presentation on your project. I learned I get seasick, so marine biology was mostly off the table for me. Yeah. And then in college, I kind of decided, you know, I went into college thinking, I really like biology. This seems really interesting. But I also knew that most people when they're going to college have no idea what they really like and change their minds and try out all sorts of different things. So I always half expected I would change my mind. And I didn't. Yeah. I took a lot of ecology classes, um, you know, trees, insects, plant, you know, I say plants, trees are plants. Um, um, You know, understanding that nobody studied primates or did a class on primates at my university, but I did a study abroad. I got to go to Costa Rica as part of like kind of the, they did it in a way at my university where it was kind of part of the normal curriculum. They made it very easy to just go. It was like a set of classes that the university gave and you just went and took them somewhere else with professors from the university. And that's where I saw my first wild primate. And I had more opportunity. We had to do these different projects at different sites in Costa Rica. You know, we go somewhere different every week and we'd have to do a new science project in the forest. Right. So I did a project on moss and I did a project on insects and I did one on primates. We did three weeks of marine biology, which turns out scuba diving is a little better because you get under the waves. But yeah, So I had that fantastic experience. And then I also actually reached out to the Lincoln Park Zoo here in Chicago. And, you know, I was interested in primates and I was like, hey, could I ever come volunteer? I had actually reached out in high school and they told me no, that I was too young, but to come back when I was in college. So I did. And so what I would do is I'd get a part-time job during my summers and work like two or three days there. And then the other two or three days I would go down to the zoo and they taught me how to observe primates and take data on how the chimpanzees and the gorillas there in the Regenstein Center for African Apes, how they were using their space and how they were reacting. They had just opened a brand new exhibit. I was actually there on the day they opened it. And so they wanted to know if they had designed it well, and they wanted to watch the behavior of the apes as they got used to those new exhibits, but also over time, so that if something changed... They could go back and look and say, oh, this gorilla is acting differently. You know, maybe there's something wrong. And so I didn't do any of that data analysis, but they taught me how to kind of do that systematic observation of the primates, which was fantastic for me. So that's where kind of the primates ecology kind of nature part of the science came and kind of emerged and developed. When you were in Costa Rica, what did it feel like the first time you saw a wild primate? That must have been such an amazing experience. It was so cool. Actually, I laugh because what we saw first or heard first were howler monkeys, which is what I ended up going on to study for my PhD. They are very loud and scary. They're one of the loudest animals on earth. Actually, the first time I heard them, I was like, what in the world was that? But it was amazing. It was, it was amazing. I was just over the moon to even be in a rainforest, let alone seeing primates. So I, that was just a fantastic trip. And then after that, I think I saw that you, did you spend a year in Mexico after graduation? Then you said studying the howler monkey. I did because everything I kept doing, I kept being interested in, um, in terms of primates and ecology. And I thought I wanted to get a PhD, um, because I thought I wanted to do research. I really enjoyed doing research. Um, and I also wanted to teach and interact with people and, you know, I didn't want to be in like, um, an industrial or kind of government lab where I had, um, different interactions with people. Like there weren't students and things around. I liked that kind of mentoring environment as well. So that was like, hmm, seems like I want to be a professor, which means you need a PhD. But I didn't want to jump right into a PhD. I didn't want to commit to this like years long degree and then find out that I hated it two years in. So I applied for grants to be able to go do a project in Mexico. I call it my fake master's. I ended up going straight into my PhD after this, but I do think it kind of served as a master's experience. I wrote up a project. I got some funding. I got a Fulbright. I got some funding from National Geographic. I linked up with a professor in Mexico who I literally just cold emailed a bunch of people in Mexico. I had also done a study abroad in Spanish in Mexico. And so I spoke Spanish and I wanted to go back to Mexico. And I thought it would be really interesting to do biology there because at least where I came from in the US, people didn't usually think of Mexico and biology. There's so much cool biology there. And so I just started cold emailing primatologist in Mexico and one responded and was like, sure, come down. If you can get money, come on down. And so that's what I did. I got money and I went down there and I did a project comparing the types of fruits that the two different species of howler monkeys in Mexico eat and how they were moving the seeds around the forest through poop. So my beginnings in poop were early and basically pulling seeds out and seeing if there was differences in sizes in the seeds in the two species or the types of fruits they were eating, et cetera. And that was a great experience. I wrote it up. I wrote it up as a paper. I didn't get an agree, but I funded a project. I did the project. I wrote up the project. And I realized that I really liked being in the field. I also had a limit to being in the field. It's hard to be limited. far away from your family and kind of cut off. I was by myself a lot of the time in forest, which on the one hand is awesome, but then after a while it can be lonely. So I learned that I'm not a Jane Goodall. I couldn't do that for years and years and years and years. And I also learned that I wanted to do something that involved like observing the monkeys, following them around, but something else in addition, like beyond just observing. I wanted to be able to kind of analyze other things about the monkeys where I could answer questions beyond just kind of, you know, how far they went in a given day or what they ate. And so that's kind of how I came into my Ph.D. So where did you end up going for your Ph.D.?

?

I went to University of Illinois in Urbana-Champaign. I worked with Paul Garber, who did a lot of kind of diet and behavior, or does a lot of diet and behavior work with monkeys that live in Central and South America. And now Mexico also. He had a few other students at the same time as me that were working in Mexico. I showed up... Paul is fantastic. He is a field primatologist. He doesn't wear shoes if he doesn't have to. We always make fun of him about that. And I showed up and I said, you know, I love being in the field. I like that. But I don't know if I want to be in the field for like a whole 12 months. And I want to do something else like in the lab as well as part of this. And he said, well, you should go talk to these other people on campus who've been talking about this microbe thing. And this was kind of where I got lucky because this is right about the time that our ability to do this kind of microbiome science was exploding. And so I went and talked to them and they were really interested in understanding kind of the relationship between brain size and evolution in different primates and these microbes and were writing a grant. And they hadn't gotten funded yet. And so I talked to them. I thought it was really interesting, but I wasn't going to like piggyback directly on their project because it was somebody else's unfunded project and I needed to start working on my PhD. But I started reading and there was this really cool paper where they showed that if you put microbes from an obese person into a mouse that has no microbes of its own. So these are called germ-free mice. They make them sterile. that mouse becomes obese. And if you put microbes from a lean person into a mouse with no microbes, the mouse stays lean. And so there's this like causal effect of microbes and obesity. And they got really excited and they figured out that it was linked to these short chain fatty acids and that the microbes from the obese person actually produced the short chain fatty acids more effectively, made more of them than the ones from the lean person. And then I remember there was this line in the paper that said, assuming that the individual does not need additional energy. It has to store that energy as fat, presumably, and that contributes to weight gain. So like if you're making too many short chain fatty acids, you have to do something with them. You store it and you gain weight. And I remember reading that line and I was like, well, if you're coming from this clinical perspective where it's somebody like me who's like sitting around in their house, maybe I don't need that extra energy but if you're a howler monkey like the ones that I was just chasing around and there's a part of the season where there's not a lot of food you might need those types of microbes that are more efficient to survive

yeah

And so that's kind of where I– that's really what I did my PhD on was I went back with the hollow monkeys. They switch their diet from season to season. When there's fruit, they eat it. When there's not, they eat leaves. That's a huge diet shift. You basically can't handle those leaves without microbes like I talked about before. And so I said, well, let's go look if these microbes are shifting in a way that it looks like they're going to help the howler monkeys survive when there's not as much food, which meant that I did have to go chase howler monkeys around again for a whole year because you've got to get those seasonal changes. But I got my lab part in there. And kind of my guess seems like it was right. That looks like what happens in these howler monkeys. And now we're seeing other types of wild primates as well. Yeah. So that was really a happy mistake. So then now are you continuing to look at primates and their microbiomes? Yes, I am. So I have a project right now funded by the National Science Foundation where we're looking at how the microbes change in three species of primates in Kabali National Park, Uganda and two species of primates at the Tuanan Research Center in Borneo in Indonesia. And so we're following all these primates around for two years and collecting really detailed information and what they're

eating.

We're collecting fecal samples to look at the microbiome. We're collecting urine to look at how kind of their energetic balances change over time. We can get that information out of urine to really try to get this picture of how microbes might fit into nutrition for these wild primates and be able to compare it across different primates in the same forest and also in different forests. I have a few of, yeah, I would say about a third of the work that's going on in my lab is some of this wild primate nutrition kind of work about a third of it is humans only and looking at environment human interaction and then third of it is kind of that human primary comparison that I was talking about that kind of evolutionary perspective okay and I know one of your recent studies that was just published was looking at people who ate whole fruits versus and vegetables versus juicing those fruits and vegetables and the differences there can you just talk a little bit about that Yeah, absolutely. That was a really interesting study that we kind of came upon because somebody was doing this study looking at the effects of juicing and different kinds of diets on health more broadly. They wanted to look at inflammation, et cetera, but they also wanted to look at the microbiome. And so they put people on either this kind of whole foods diet this food plus juice diet or a juice only like a juice cleanse diet over a relatively short period of time it was only you know a matter of like days and wanted to look at how the microbiome changed and it was interesting because you know I think juicing gets promoted a lot as something that is a health benefit, right? That it's cleansing you and washing out toxins and maybe rebalancing the microbiome and things like that. But what we found was that that didn't seem to really be the case and that the people that were consuming a juice-only diet, and to some extent the people that had the food plus juice diet, showed shifts in their microbes that actually looked different. negative potentially. So shifting towards more of these microbes that break down sugar rather than fiber and things that are associated with promoting inflammation rather than tamping it down. And we think this is because what happens when you juice is that you're taking a lot of that fiber out of the fruits and vegetables, right? And in terms of the microbiome, that is the part that's really beneficial, the kind of promoting that healthy microbial community. So it really seems that in that sense, this juice diet, at least the specific one that we tested in this study, is not having that benefit that people want. And you're actually pulling out the good stuff in terms of the microbiome. So, yeah, even though you have the nutrients and the vitamins, they're still there without the fiber. There's... more of a negative effect than a positive effect correct yeah right so yeah you're getting right the nutrients the vitamins etc from the fruits and the vegetables but you're also putting a whole lot of sugar into your system simple sugars and kind of eliminating that step of digestion where the microbes are degrading that fiber and producing the anti-inflammatory things you know and to some extent if you're putting that much sugar through the body you know a lot of it's going to get absorbed in the small intestine but some of it will get to the large intestine and those microbes will then shift over to using the sugar because it's easier for them and when they do that the things that they're making as a result of that process are not necessarily good for our health yeah because i mean there's obviously been so many studies on sugar sweetened beverages and not just like sodas and energy drinks and Gatorade and just plain old juice. So is this the mechanism then behind why those seem to be so unhealthy? Or is it just that the large influx of sugar into our system is, that's one part of it is the microbiome, but then it's just also our body trying to like insulin and trying to process that sugar is what causes a lot of the problems in people. Yeah, I do think it's both. You know, biology is complex. And so I think with the microbiome field, like any new field, everybody wants to jump on that wagon, right? And say that this is causing everything. And it does have a huge effect, but it's definitely not the only thing. So yeah, I think those microbial effects contribute to it. But like you said, there's also the direct negative effects of having that much sugar in the body. So... I think you kind of studied this too, just the typical Western diet of more meats, less fiber, processed sugar and things like that. What kind of overall effect is that having on our microbiome? Bad. You don't need science to tell you that. There you go. That's the surest answer. Yeah, I mean, the Western processed food diet is really bad in a lot of ways. Like you were saying, directly bad for us, ignoring the microbiome side of it. But if we think about the microbiome side of it, Right. You don't have a lot of the fiber in there. You have a lot of sugar in there. You tend to have a lot of fats in there, which, as I kind of alluded to earlier, that can, you know, if you're digesting fats differently, that means bile acids are coming into the system differently and that's interacting with microbes differently. So, right, we think there's a risk of eating a lot of red meat and part of that risk comes through the microbiome. And lack of fermented foods is another thing in a lot of these processes. diets, right? Even things that traditionally were fermented are not really anymore, right? What do you mean? Can you give me some examples of the fermented foods? So fermented foods would be things like cheese. I think ketchup was originally fermented. Chocolate has a fermentation process. It goes through bread, right? Sourdough bread. And then you can think of things like kimchi and sauerkraut and yogurt and kefir. If you think about it, kind of most every culture around the world has some kind of staple part of their diet that's fermented. Same thing with bread, like a lot of the process, you know, the bread, white bread in the aisle that you get out of a bag. That's really different than making sourdough bread in your house. because you're not using that slow microbial process. You're using baker's yeast, which goes really quickly. It doesn't break things down the same way. It's not producing the same compounds as part of it. And so you're losing some of those dietary inputs that you would get from a result of even just processing the food differently. So overall, maybe just the less processing, the better. If you can choose foods that are more whole, less processed. Absolutely. It's healthier. To change subjects again. So I saw one of the things that I was interested to talk to you about was some of the work that you do in Chicago to kind of engage the public. I think that if we're doing science, we need to be able to explain the science we're doing to people. Um, and it's all well and good for me to do studies and publish them, but if I can't explain it to somebody, um, and help them understand kind of what we're doing and why I think a lot of the point is kind of lost. Um, And I do think we've seen that kind of recently in the U.S. without going too far into kind of politics. But I will say that I don't think we have great science education. And so I don't always think that kids or even adults kind of understand what scientists are doing, why, kind of how the process works, etc. or even understand what it means for me to have data, right? And that like, I think this is the pattern, but I'm never sure that it's the pattern. I'm always trying to work to get better, right? But that doesn't mean I don't know anything. And I think that sometimes gets confused. So, you know, trying to communicate what we're finding and what it is, but also, you know, like you're doing such a good job with the podcast, right? What does it mean to be a scientist and do science? Like, what's that really about? So are there specific... projects that you've worked on? Yeah, there was a project or, um, You know, there's a lot of kind of yearly events that we try to go to where we're engaging kids in kind of the middle school realm of things to talk about the types of research that we do. So there was one for a long time that I think unfortunately kind of tailed off a little with the pandemic, but it was middle school girls and they would do a whole day going to kind of different stations with different researchers during the day to learn about an aspect of their work. So we would have them, um, talking about what's antibiotic in their homes, what's probiotic in their homes. We actually did this virtually a couple of times too. Um, you know, what would happen, you know, if we have different colored beans that are different microbes that like different foods, what happens if your diet changes like this and have them kind of counted out, right. Um, you know, talking about what it's like to go chase monkeys around. Um, So yeah, we try to get into schools as much as we can. I've done things at the zoo. You know, right now I'm working with some urban gardens in Chicago because we're trying to do a project on how being in a garden can positively affect your microbiome, like working with dirt. If that, you know, like I was talking about, we think having that outdoor exposure is a good thing, trying to actually test that. But it's been fun to like talk to and learn from the people that are setting up these gardens and kind of creating this service for the community. So yeah. Yeah. What would you say then is kind of the overarching goal of your work? Like in 20, 30 years, if you look back, like what do you, what do you hope you're going to accomplish or what do you hope that you will learn? And is it more about like the curiosity of figuring out truth of where we came from and things like that? Or is it about using this work to help other people? Or is it both? Or kind of what are your goals? Yeah, I think they're twofold. It would be two main goals. I think, you know, one on kind of the basic just curiosity side, I am really interested in trying to figure out if we can find evidence for that microbes actually contributed to human evolution, right? There's this idea out there, but can we actually show it better and come up with data to show that? I think that would be fantastic on kind of the basic curiosity side. On the more human engaged side with the gardens and the diet, et cetera, I'd really like to be able to contribute to people's understanding, as you were talking about, in terms of lifestyle, even contributing to policy, things like that. What are things that we can do to try to promote these microbiomes that we think are better for people in kind of a preventative health way, right? So before or when somebody is sick, in addition to some kind of traditional medical interventions, can we think more about... diet and being outside, et cetera, kind of an integrative medicine perspective. I think along with that, really bringing this awareness of microbes into like a health inequities perspective. So thinking about if the environment is so important for determining what types of microbes we have, then we really have to think about what types of environments people are living in. If they have access to non-processed food, are they living in a food desert? Do they have safe outdoor green space or not? Should people be living in multi-generational households to the extent that it's possible to be sharing microbes from grandkids to grandparents, et cetera? Trying to kind of contribute to our understanding of those pathways would be my other... kind of more health, human health focused goal. Yeah. Um, and my last question, uh, what do you, what do you like to do to have fun, to relax? Like, do you have time for that? Or you seem pretty busy or there's certain things that, that make you happy in that way. You know, I don't have a lot of time. Um, I have two kids right now and we got a puppy in November, um, after me saying no for a year and a half, um, cause I knew it was going to happen. Um, So there's not a lot of time outside of that. I mean, when I come home, it's all hands on deck with my kids. I have a very, a pretty strict work-life balance. So I think being with my family is my fun. I jog. I do CrossFit. That keeps me sane. Yeah. I like to read and I do like being out in the garden. It's been kind of fun with this new garden project, um, that I kind of have to go be in a garden as part of work. Um, so yeah, I still, I still like that being outside part. I just don't get quite as often. Do you watch TV? Do you watch Netflix? I do watch Netflix sometimes. I don't fall asleep on the couch. Yeah. Yeah.

That always happens.

I would say that that's something I could not do. Like, 15 years ago. And now I'm very good at it. Falling asleep on the couch or watching Netflix? No, falling asleep on the couch. All right.

All right. Well, I think those are all of my questions. Thank you so much for speaking with me. This has been

so fascinating to hear. I hear so much about the microbiome. I have like a basic understanding, but this was so fascinating to hear about it in primates and humans and you know, how it all comes together in evolution. So, so thank you. Thank you for sharing your time. I appreciate it. Yeah. Thanks for having me. That's it. Our theme music is called discussion and was composed by folk acoustic. Send along any questions to socializing with scientists at gmail.com. Subscribe to the podcast on your favorite podcast app. And we'd love it. If you could give us a five-star rating or a short little review, follow us on Instagram at socializing with scientists and on blue Thanks

so much, and we'll see you next week.