What poop says about your health | ASU KEDtalk

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For Meli'sa Crawford, talking about poop isn’t gross or impolite — it’s an important part of a day’s work. She studies poop to learn about the microbiome, or gut bacteria, and to understand how gut bacteria affect your health.

April 9, 2019

ASU KEDtalks: The podcast with Meli'sa Crawford
Video transcript

In my grandmother's household, she would say, that if we were having trouble pooping, then we may be sick. This concept would intrigue me as a child. So, you mean, if I can’t poop, then somethings wrong with me? Well, why poop? I didn’t know it at the time, but my grandmother was planting the first of many seeds used to help me develop into a future gastrointestinal researcher. Which also means, that other peoples’ poop is a huge part of my life.  

I grew up in South Phoenix, which was considered to be a food desert. While there were many grocery stores in the area, the quality of the food was disappointing, and many families, like my own, could only afford fast food. Needless to say, I saw many family members and friends struggling with their health. Which made me wonder if a lack of bowel movement were to blame.  
Now, my grandmother isn’t a scientist, but she was definitely on to something. Poop can tell us about our health.  

The gut microbiome is associated with many metabolic and gastrointestinal diseases, like obesity, type 2 diabetes and inflammatory bowel disease. 60-70 million people are affected by digestive disorders, and over 97 billion prescriptions are written annually to treat these debilitating illnesses.

But a poor diet is the most important factor that can determine whether you get metabolic and gastrointestinal diseases.  

In our lab, we examine how a high fat diet can alter gut bacteria and what passes through the intestines. We’ve found that a high fat diet can increase bacteria associated with disease. And it can also increase inflammatory proteins. In most cases, increasing fiber intake through fruits and vegetables can improve gut health.  

So, the majority of the information that researchers and doctors use to help develop new treatments starts with knowing the composition of your poop. For example, you can donate your fecal samples to a nonprofit stool bank like OpenBiome. With that information researchers can develop pills that contain healthy fecal microbes to treat patients suffering from GI disorders. My hope is that one day we can improve food quality and accessibility for underprivileged areas, so that one day we can eliminate disease risk.

Podcast transcript

Boudreau: Welcome to ASU KEDtalks, the podcast. I'm your host, Diane Boudreau, and I'm here today with Meli'sa Crawford, an ASU PhD candidate in biology who studies the microbes that live in our guts. Welcome, Meli'sa.

Crawford: Thank you.

Boudreau: So one of the first things that you said when we met was, my whole life is poop. I don't think I'll ever forget that. What specifically can we learn from looking at poop?

Crawford: Well, you can tell a lot about a person from their poop. More specifically you can tell about their health. So if they're unhealthy, their microbes in their poop would be different than a person who is healthy. So, for example, what we eat can affect the microbes that live in our gut. And so in a healthy person who's probably active and who works out and who eats like a normal balanced diet, they would have more diversity in their gut in comparison to someone who is unhealthy, quote unquote, unhealthy.

Crawford: So maybe not as active. Who eats a diet that is more enriched with fat. You would have less diversity in your gut. So less microbiome or less microbial diversity. And that can pose a problem. So basically your poop can tell you how healthy you are. It can tell you if you're active or not. It can tell you, yeah, a lot about your metabolic health overall.

Boudreau: I'm intrigued by this notion that we have this whole ecosystem living in our guts, this microbiome. What is in there specifically?

Crawford: So more, so there's bacteria, there's fungi, and they're just, and they interact with each other basically. So, in the sense of other things, I'm not quite sure, but I am aware that there are like over trillions of microbes. So trillions of these bacteria and fungi species living in your gut, these interactions can have like a broader impact on our health.

Crawford: And so in terms of the microbiome, if there's less diversity, so if there's only a couple of species within our gut, um, it's basically indicative of a problem. So it's indicative of like either obesity or diabetes, where in a healthy person there's more diversity, you know like we discussed, and that greater increase in diversity leads to a greater effect. So bacteria can metabolize things, can release fatty acids that can, you know, help in terms of either eliminating metabolic risk factors.

Boudreau: So what effect do they have on our bodies? What do they impact?

Crawford: The microbes in your gut, like bacteria, they can metabolize things that we can't. And so they use what we eat as an energy source. So we share this nice symbiotic relationship with them. They help us, we help them. In some cases there are bacteria in our that can be harmful. And so if we're not careful with what we eat, or just around that notion of being healthier and eating better foods, there are bacteria that are gram negative and they have, a wall that has something called lipopolysaccharides. And so in most cases, once you're eating all this bad food and you're increasing the abundance of these gram-negative bacteria, that can have a terrible effect on your gut. And so that can release endotoxins. So endotoxins can cause inflammation and that can, that inflammation can flow systemically throughout your system and can affect other organs. And so basically we want our bacteria to be happy in our gut. We don't want the pathogenic bacteria causing inflammation. So this is why it's important for us to increase that abundance of good bacteria, quote unquote. And then they can also promote good immunity in our gut.

Crawford: And so they can promote the immune system to work actively, um, instead of the negative aspects of the microbiome. Yeah.

Boudreau: And then you said these endotoxins can get into the rest of your body, right?

Crawford: So they can flow systemically.

Boudreau: So what kinds of health issues are we looking at here?

Crawford: Yeah, so one of the things I look at the most is how that affects the actual gut barrier. And so once you're eating fatty foods and your immune cells can attack these gram-negative bacteria releasing endotoxins, those endotoxins can promote the production of inflammatory proteins. So these inflammatory proteins can then affect the tight junction. So what's holding our cells together, they can affect that by breaking them apart and causing holes in our gut. And so that's what I want to look at more into how that's causing gut disease. And then the inflammatory proteins that flow systemically throughout our blood, they can affect the heart, they can affect your liver, they can promote other inflammatory diseases.

Crawford: And so that's what we want to focus on too, is just how is your bacteria in your gut affecting every organ in your body and causing all these diseases.

Boudreau: So, okay, these bacteria have an effect on us. How do we affect them, in turn?

Crawford: We don't take care of them like we should. So, and again, that goes with how healthy we are. And of course, every environmental factor around us. So that can, we can affect the microbes in our gut by just eating unhealthy and then air pollution. That's another big factor. And so there's been a lot of research on how the particulate matter in the air. So basically all of these bacteria and fungi in the air, how they're causing a negative reaction in our gut and how that can actually increase the risk of inflammatory diseases or metabolic complications like obesity and diabetes and things like that.

Crawford: And so if we, and it's complicated because everyone's different. So even if I were to say that I can help my microbiome this way, by exercising or eating healthy or staying indoors because air pollution is scary, that may not have the same effect for everyone. And so that can cause a really big problem too.

Boudreau: You've kind of touched on this a little bit, but do you have any advice for listeners who are saying, Oh my gosh, I want to have, I want to have a healthy microbiome. What can I do? Obviously, staying away from a high fat diet would be one piece of advice. Is there anything else that we know that we can tell people?

Crawford: Yeah, that would be ideal. I know there's a lot of information on the market that's talking about, you know, maybe you should increase supplementation of probiotics and prebiotics or you should exercise cause that'll always have a huge impact on the gut microbiome, or yeah, eating healthy. But it really depends on who you are and, but those are some of the easier ways to shift your microbiome in a more positive direction. But if we wanted to know how to drastically change it, I think that starts with knowing exactly who you are and knowing the composition of your poop, you know, knowing what's in your poop and the type of microbes that are there or that are residing in your gut. And then we can take it from there. And I feel like that's where treatment is going towards, like it's going towards that direction.

Boudreau: Is there a way now to know to, to be able to find out what your gut microbiome is?

Crawford: Yeah, which is so funny cause I was so excited when I found this out that you can donate your stool samples, you know, to OpenBiome. So, although, in a sense OpenBiome is there to collect your stool samples and then to just to see if you like, it's healthy enough, like the microbes in your poop are healthy enough to treat someone who is actually diagnosed with a gut disorder. So of course they make fecal pills, so poop pills that contain these healthy microbes. So maybe that can give you an idea of your fecal composition. And of course there might be clinical studies that are actually, try and get people in to donate their fecal samples to identify like the composition of their poop. And then the huge Human Genome Project of course has been one of the most defining factors in microbiome research. And so I feel like in the Western culture we have an idea of like the average composition of our microbiome.

Crawford: You know, the bacteria duties, to the Firmicutes, like how they interact with each other. But really if you wanted to be more personalized, I feel like that's what we need to do more research on. That's what we need to find out. Yeah. Maybe there are other sources out there, but yeah.

Boudreau: So you mentioned the need for more research on this. What do you personally want to study in the future?

Crawford: So obviously I love what I do. I love microbiome research. But my true passion really does lie in knowing how the microbes and knowing what we eat and knowing environmental factors, how all of that is contributing to intestinal permeability. So basically again, those holes in your gut and increase of holes in your gut and how that can lead to other gut disorders. So yeah, I'm passionate about that. And then how is that even developing or increasing the risk for gastrointestinal cancers?

Boudreau: When we talked before, you talked about food deserts and how you grew up in a food desert and how that affects the quality of your diet and then that affects your microbiome and that affects your health. So there's this cascading effect here. And you mentioned that you were sort of interested in looking at also food accessibility. Is that something that you'd like to do more with in the future?

Crawford: Oh, definitely. Yeah. I think that comes into getting more involved into science policy, so food policy, and how to regulate what's being shipped to stores on the South side in comparison to Sun City, you know, there's a huge difference in the quality of food in these two areas. And why is that? Why is this more underprivileged area receiving food that's of lesser quality? So there has to be an answer to that, and there could be a billion possibilities, but I feel like that's something I would want to pinpoint into why, because yeah, in these underprivileged areas, you also have a higher risk of metabolic syndrome, higher risk of obesity and diabetes and cardiovascular disease.

Crawford: And of course, the majority of that starts with what you're eating. And is it expensive, and are these families able to afford what they're being given in these grocery stores? Cause it's like I said before, my family could only afford these fast foods, you know? And I remember my mom would always complain like, gosh, like it cost so much, you know, to buy a salad and it's so much more cheaper to just go to Taco Bell and get a meal, you know? And that would always intrigue me too. Like why, why would it be so expensive? And so I think that would be something I would want to look more into.

Boudreau: In your KEDtalk video, you mentioned being inspired by your grandmother when you were a child. Obviously, other things happened in the course of your lifetime. How did you end up as a PhD student in a microbiome lab? What was the path you took?

Crawford: Yeah, so, it's funny because I didn't think I would ever be a PhD student. I didn't think I'd ever apply to PhD program. But I worked at the Arizona Science Center forever, for about year or so. And that really helped me increase my interest in the sciences right after my bachelor's. But my grandma was one of the defining factors, I think, because she was very, she insisted that whatever we did, and no matter what it was, if we were having a bad day, go poop. If you were sick, go poop. Just, just get it over with or have you been pooping, whatever? And I'm always like, why would she say that? Like why was this always a big, like component in her life? Like just poop. It'll be okay. And it made me wonder, yeah, a lot.

Crawford: Like why would this be important? And I feel like once I, after I worked at the Arizona Science Center, I did clinical research, and it was always in the back of my mind, gastrointestinal research. But I'd never, I don't know, I think the interest, something, it just didn't peak just yet. You know. So when I did clinical research, I was working with obesity and diabetes patients a lot. And then when I got to ASU, I worked in a synthetic biology lab first, and that was completely out of my league. It was like an engineering program. And I was like, okay, this is not for me and I need to find something a little bit like, something that's going to cater more to my interests. And so, after about a year in the engineering program, I applied to biology and got accepted and my PI now, like she's not a microbiologist, we hardly do microbiome research.

Crawford: It was just an interest of mine that we were able to kind of push in the right direction. And so she actually does, she's an avian physiologist so she works with birds, but we also, yeah, study obesity metabolic syndrome in humans and rat models. And so I just had this interest of, you know, the gut and I watched a TED Talk on the microbiome and that was like, okay, this is actually going to work for me. And so she put me on a project looking at like liver function and high fat diets and that just kind of increased my interest a lot, peaked it a lot. And then I was like, what else can I figure out about the GI system? And there's so much more to it. It excites me. It's like one of the most exciting topics to me.

Boudreau: Since you're in the throws of finishing your dissertation, right, do you have any advice for students who are considering maybe getting an advanced degree in science?

Crawford: I would tell them to, well first I would say this, that it's okay if you don't know exactly what you want to do in the beginning, because I feel like I spent a lot of my time wishing I knew, just to try and figure it out because I felt like there was a lot of pressure to know immediately. When I started my first PhD program, before I applied to biology, I was kind of in the midst of trying to figure out what I wanted to do and rotating through labs and trying to figure out if this lab was the right one for me. But I realized that it takes time. You know, it takes time to find your passion sometimes, like it doesn't come immediately.

Crawford: And then I would also say that it's really important to find the right PI. I feel like a lot of grad students struggle with finding a lab for them. So they may think the topic is correct, but the PI may not match your personality. And that PI-mentee relationship is one of the most important relationships you'll have throughout your entire PhD because they're like a parent basically. Yeah. And they're there to help you. They're there to guide you on your way throughout your PhD. But you also have to be happy. You have to love what you're doing and you need to be content with the work you're doing and happy with this relationship. And if you're not, I think that affects the entire, your entire experience.

Boudreau: Something you mentioned too, you talked about, um, the OpenBiome project and how they can, they're working to develop treatments. So you're saying that you can take somebody's poop, and make medicine for somebody else basically with that. How does that work?

Crawford: There's been this idea about poop pills, fecal pills that contain healthy microbes. So it's really easy to isolate the microbes from your poop, you know? And so I think with that or even, once they isolate it they can or sterilize the poop, well not even sterilize cause that eliminates all the microbes. But like, yeah, just to isolate the microbes, put it in a pill, give it to someone. Because the idea is that their microbiome is less diverse and because of that, the less diverse their microbiome is, probably the more problematic it is. So they want to increase diversity in the gut. So again, like that healthy microbiome has more diversity, more microbes running free, you know, that are more beneficial to the type that a person who's suffering from a digestive disorder would have.

Boudreau: And are these being used?

Crawford: Oh yeah. Yeah, yeah, yeah. There's been a lot of clinical research on that actually. Which is exciting. It makes me want to donate my own poop. I'm trying to figure out what the criteria would be. You know, cause I'm sure there's like a very selective process for it. I don't think anyone can just walk on up and poop for them.

Boudreau: If you're interested in more from Meli'sa Crawford, watch her ASU KEDtalk video at research.asu.edu/kedtalks. Subscribe to our podcast through your favorite podcast directory and find us on Facebook and Twitter @ASUresearch.

 

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