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A Few Minutes With E. 58

A Few Minutes With Jacob Allen

AHS media relations specialist Vince Lara speaks with Jacob Allen, an assistant professor in the Department of Kinesiology and Community Health, to discuss his research on how diet, exercise and stress influence the gut microbia community.

Click here to see the full transcript.

VINCE LARA: Hi, and welcome to another edition of A Few Minutes With, the podcast that showcases Illinois College of Applied Health Sciences. I'm Vince Lara, and today, I'm speaking with KCH Assistant Professor Jacob Allen about his research on how exercise, stress, and diet influence gut microbial communities.

So I'm talking with Jacob Allen, who is a new addition to the Department of Kinesiology and Community Health. And, Jacob, I notice from your CV that you had done your undergrad and master's at the University of North Carolina at Chapel Hill. And yet you left Chapel Hill, which is a lovely place in which I lived for a while, for Chambana, which we're covered in snow this morning. Tell me, what made you do that? What prompted your move here?


JACOB ALLEN: That's a good question. Well, so I did my bachelor's in exercise science with a minor in biology. And coming out of undergrad, I didn't really know what I wanted to do-- surprise, surprise, a little bit young. But I was interested in exercise physiology, and so I decided to stay on and do a master's program in the Exercise Physiology group at UNC-Chapel Hill.

And I did my masters in working with breast cancer survivors, where we looked at how exercise affected inflammatory markers in these patients that were coming off of breast cancer treatments to see if exercise could reduce some of the systemic inflammation they experienced. So that was my foray into exercise. And then because I was looking at inflammatory markers, these proteins called cytokines in the blood, I started getting interested in immunology.

And at the time, and still is, Jeff Woods, Dr. Woods here at University of Illinois, was prominent and one of the few exercise immunologists in the field. So I figured if I was going to study exercise and study the immune system, I should probably go get a PhD with somebody that knows what they're doing. And so I looked up Jeff's name and gave him a call.

And that's what started my process of moving to Champaign to do my PhD in 2013 to look at exercise and the immune system. And so I came to Illinois, and I took off from there, where we started to look at both the immune system, but also the microbes in the gut and how the microbes affect the immune system. So I guess it was more of a career path that took me from Chapel Hill, where it's a little bit warmer, to Champaign, Illinois.

VINCE LARA: Right, yeah, absolutely. And then the opportunity to work with Jeff obviously is a big part of it.

JACOB ALLEN: Right, yup, it was, definitely.

VINCE LARA: Yeah. So you talked about how your research focuses on exercise and diet and how they influence gut microbiota. What led you to study that? Usually there's some sort of inspiration to what a researcher decides to study. Was there something in your early life that led you to look into that?

JACOB ALLEN: You know what? I wish I could say there was some beautiful epiphany I had or something like that. But I can't really tag it to anything specific. I'd say I'm interested in questions that we don't understand, and that's probably why I did biology.

And when I started in Jeff's lab, there was this emerging topic of the microbiome and these trillions of microbes that live in our gut that we still don't know exactly what they do. And so it kind of just spiraled into studying it. Again, like I said, I was an exercise scientist looking at how exercise affects breast cancer survivors.

And it got me interested in the immune system. And then being interested in the immune system led me to study the microbiome. And what we know now is that the microbes in our gut are really important for training the immune system and establishing the immune system, and then in many inflammatory diseases, affecting the immune system. And so the study of the microbes tied in directly with my interest in immunology. And so that's how I got to studying the gut microbiota.

VINCE LARA: How granular can we get in terms of, if you change one food, if you stop eating one food, can you determine how that affects the gut and how it affects disease?

JACOB ALLEN: That's a great question. Number one, I'll say, it depends-- depends on the food. We know a lot about-- relatively a lot-- about certain types of food with regards to the microbiota. One of them is dietary fiber and something that our lab is interested in.

So fiber comes in different forms, but in one of the forms, it's a soluble, fermentable fiber. And what that means is that it can reach the colon, where most of the microbes are. And the microbes use that fiber as food, as a sugar source.

And so what we know is that by feeding the microbes with this fiber-- and again, there's various types of it-- we can change the microbiota quite extensively. What's still not understood is how different types of fiber feed the microbiota differentially. And does that matter for our health?

And what's important is that once the microbes get a hold of these-- this food type, this fiber-- they can degrade it into these bioactive molecules that then affect our immune system. So we're still trying to understand that process of how the microbes feed off of these-- off of our diet. What type of metabolites do they produce? How does that change the microbial communities? And then how does that all affect our immune system and our health is our interest in our lab.

VINCE LARA: What you've said is that you wanted to provide a new perspective on environmental conditions and microbiota. Is that tying into what you're looking into?

JACOB ALLEN: Exactly. You know, our lab is named Integrative Microbiota Lab. And the reason for that is that I think that in science, we're really good at isolating things and tying down to what we call a mechanism, which is really important. And that's part of our lab, too.

But in especially humans, as we walk through our daily life, we're doing all sorts of things. We have different exercise patterns. We have different levels of psychological stress. And that's another component of my lab, is looking at how stress affects the microbes as well.

And then obviously, we all have different dietary patterns. And so trying to tease out those factors and how they regulate the microbiome in a daily life is the purpose. And my long-term goal of my lab is to look at these individual environmental factors in isolation. And then long-term, how are they all together affecting the microbes in the gut?

VINCE LARA: Can you tease out things like physical stress versus mental stress? Or is that something that you even can separate?

JACOB ALLEN: Another great question. There's debate among this in the field of how to define stress in humans. And obviously, it's all based off of the experience of the person.

But we can measure certain biomarkers that correlate heavily with stress. So we know some classical pathways that are activated by psychological stress-- the hypothalamic pituitary axis, which ultimately results in the release of a glucocorticoid called cortisol, which I'm sure many are familiar with. And so we can look at levels of cortisol in the blood, but also, more long-term, elevations of cortisol in things like hair roots and stuff like that to see if these individuals are experiencing acute levels of stress, which we all experience, or if they're experiencing stress on a chronic level on a daily basis, where we see this long-term elevation of hormones associated with stress.

So the short answer is it's complicated. But we can at least get somewhat of a diagnostic of how stressed people are or individuals are based off of some of the hormonal responses we see in the blood and other tissues.

VINCE LARA: Interesting. You know, you recently received a grant along with Jeff Woods to study age-related dysbiosis and physical resilience. What can you tell me about that project? I mean, first of all, what's age-related dysbiosis?

JACOB ALLEN: Yeah, so first, the word "dysbiosis," for those that don't know, is essentially a broad term to suggest a disrupted microbial community in the gut. And so there's various forms of, quote, "dysbiosis." But what we know is that if the community of microbes in your gut is healthy, it usually is fairly stable and goes through similar-- has similar patterns amongst individuals that stays fairly stable over time.

What we see with, quote, "dysbiosis" is that those communities become less stable and less even. So you sometimes get what we call pathobiont species that expand in the gut. And these are potentially bacteria that might induce some negative consequence on our immune system or other components of physiology. And so that's what we term-- what we call dysbiosis. And what the age part is that there's accumulating evidence that aging, getting older, might contribute to some form of dysbiosis.

And what we're studying with this grant-- so it's a one-year grant funded by the NIH that will hopefully extend into a longer grant-- is to see how antibiotic exposure affects the microbiome in aged populations. And there's a couple of reasons for this. One of them is that aged individuals tend to consume antibiotics more extensively because they're experiencing more sickness as they get older. And so we want to study it on that level.

And number two, obviously, these antibiotics affect the microbiome. And so we want to see if a, quote, "aged microbiome" responds differentially to antibiotics versus a young, healthy microbiome. And so to test this, we're using first, a preclinical model, which is a mouse model, to test these hypotheses.

And tying it in, we think that those microbes, if we disrupt them in old animals, there's going to be consequences both within the gut, but we also think that is affecting their physical resilience-- so how well they perform on particular tasks such as exercise tasks. And so that's our hypothesis going in. And of course, we don't know the answers yet, and that's why we're running the studies.

But we think that the aged animals will respond differentially to the antibiotics and maybe not recover as well. And that might lead to some potential issues with how they move and how they respond to challenges. So that's the purpose of the grant, if that makes any sense.

VINCE LARA: Yeah, absolutely. How symbiotic is the relationship between exercise and gut health? Does one influence the other more?

JACOB ALLEN: Yeah, that's a great question. So some of my PhD work showed that exercise changes the microbiome. And it increases some beneficial metabolites that we think are health-promoting.

And one of them is called a short-chain fatty acid that initiates some overall anti-inflammatory and beneficial effects on our tissue. Now, whether it's, quote, "good" or "bad," I think we still need to figure out. There's definitely changes with exercise and the microbiome. But again, trying to delineate the long-term effects and whether it's good or bad is still up for debate and up for what we need to investigate with our science.

Your other question-- does gut health affect exercise? And I think that that's another open question in the field. Is there some gut-brain signaling that affects motivational behavior to exercise? And that really has not been investigated at all to my knowledge. So I think you bring up a good point. And it's something we don't know quite yet.

VINCE LARA: Yeah. You mentioned that you're hoping that this grant with Jeff is going to be a long-term grant-- multiyear. But researchers always have to look to the next thing, right? And so I'm curious what you're working on or what your next big project might be.

JACOB ALLEN: Yeah. There's a couple. Currently, I did some work that was independently funded at the end of my postdoc that I was able to take with me to start my lab here in Illinois, focused on some of the stress effects on the microbiome. And so we're currently, in the lab, really interested in how the microbes interact with the cells that line the gut, called epithelial cells.

And what we found is this really intricate interaction between the gut microbes and these epithelial cells. You think of it as like a tit for tat. As the epithelial cells, which are our cells that line the gut, produce some molecules, they change the microbes. The microbes then feed back and change those epithelial cells.

And what we found is that stress, for some unknown reason, really changes the profile of these epithelial cells. And we're not sure why yet. But what the evidence is pointing towards is that those changes in epithelial cells with stress is really driving the microbial changes that we see in the gut, and potentially in negative ways.

And so we're trying to understand that process in a little more detail in our lab currently. So that's the next frontier where we're focused. And then we have some other focuses, too, particularly with exercise.

And going back to the integrative portion of it, we're interested in how exercise and dietary fiber interact to modify the microbiome. We know that both in isolation change the microbiome. But really, not a lot of work has been done with a focus on how the interaction of diet and exercise might change the microbes and what that might mean for our health. So that's another focus of the lab currently as well.

VINCE LARA: My thanks to Jacob Allen. For more podcasts on Illinois's College of Applied Health Sciences, search A Few Minutes With on iTunes, Spotify, iHeart Radio,, and other places you get your podcast fix. Thanks for listening, and see you next time.

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