“I had not planned to go into this field. But when I was at UNC Chapel Hill, I was in a lab that studied a nutrient called choline. And all of a sudden, all this literature came out about choline. a microbial metabolite called TMAO. And guess what? That is derived from the breakdown of dietary choline from the gut microbes. So that sort of led me down that path to start with.” “So, the gut microbes, which by the way, are all over the body, but the largest numbers are, are in your gut or in your colon. They do things like process nutrients and metabolize them. They can impact how some diabetes medications work, like metformin, which is a pretty common medication for people with diabetes. They also impact things like immunity and inflammation, which we know don't work the way they should sometimes in people with things like diabetes or obesity.” “So, the bottom line is that we are the ones that feed the gut microbes. So it goes into our mouth, most of it gets absorbed in the small intestine, and that's where most of the magic happens in the body. But there's a small percentage, which we control based on our food choices, that ends up making it all the way down the gut to the colon, where the microbes can ferment those foods and perform various functions. So diet is by far the most fundamental way that we as humans impact those gut microbes every single day because we all got to eat at least once or twice a day.” “So, transdisciplinary just means across disciplines, and back, you know, many, many decades ago, it was, you could just envision this, right? The lonely scientist in the dark lab, in the corner, pipetting and just trying to figure all this stuff out. by him or herself. And we have just changed so much because now we don't just look at one gene. We can look at all the genes. We don't look at one microbe. We can look at all the microbes.”
In today’s episode, we are honored to have Dr. Karen Corbin. Dr. Corbin will discuss optimizing gut health through diet, especially in the context of diabetes. Tune in for valuable insights that bridge the gap between research and real-world applications in the realm of nutrition and health.
Clinical Translational Scientist at the AdventHealth Translational Research Institute focused on advancing gut microbiome and human metabolism research. Founder and Chief Geek at Geeks That Speak with a mission to elevate the voices of scientists through scientific storytelling.
[00:32] Shireen: In today’s episode, we are honored to have Dr. Karen Corbin join us. She talks and discusses how to optimize gut health through diet, especially in the context of diabetes. Tune in for valuable insights that bridge the gap between research and real world applications in the realm of nutrition and health.
[00:53] Shireen: Dr. Karen Corbin is a clinical translational scientist at the AdventHealth Translational Research Institute focused on advancing gut microbiome and human metabolism research. She’s the founder and chief geek at Geeks That Speak with a mission to elevate the voices of scientists through scientific storytelling. Welcome, Dr. Corbin.
[01:17] Dr. Karen Corbin: Thank you so much for having me.
[01:19] Shireen: And also a pleasure having you on. Dr. Corbin, I would love to start with your why. What really inspired you in your career as a registered dietitian? What really led you to that?
[01:30] Dr. Corbin: So, I knew since I was a little girl that I wanted to go into science, so I started in biology. And then I had this sort of flip in my mind where I said I want to use science to help people and I stumbled across dietetics. You know, back then we had catalogs on paper, there weren’t a bunch of websites, so I had to figure things out sort of experientially. So then I decided that nutrition and dietetics was the field for me.
[01:55] Shireen: I love that. Thank you for sharing that. And next, I, you know, you read in your bio, this focus on gut health and like gut microbiome. Tell us that journey and what led you to that.
[02:05] Dr. Corbin: Yeah, that was also not planned. So for anybody out there thinking that their career doesn’t make sense, it’s okay. You just take steps. I had not planned to go into this field. But when I was at UNC Chapel Hill, I was in a lab that studied a nutrient called choline. And all of a sudden, all this literature came out about choline. a microbial metabolite called TMAO. And guess what? That is derived from the breakdown of dietary choline from the gut microbes. So that sort of led me down that path to start with. I set it aside for a bit because I was doing other things. And then when I came down here to Orlando, my boss and colleague and friend, Dr. Stephen Smith, was able to win a grant in collaboration with Rosie Crashmall McBrown at Arizona State that was focused on the gut microbiome. And he said, “Will you join us on this journey?”. And I said, “Yes, this stuff is really exciting.” So, uh, it was a happy accident.
[03:01] Shireen: Lovely. And now help us understand some of these relationships. Now, of course, for this episode, we’re really focused on that gut microbiome, but there’s this relationship, this influence that gut microbiome has this influence on diabetes. Now, help us understand what that is and why is that relationship important to explore?
[03:21] Dr. Corbin: So the gut microbes, which by the way, are all over the body, but the largest numbers are, are in your gut or in your colon. They do things like. process nutrients and metabolize them. They can impact how some diabetes medications work, like metformin, which is a pretty common medication for people with diabetes. They also impact things like immunity and inflammation, which we know don’t work the way they should sometimes in people with things like diabetes or obesity. So there’s all these connections, most of them, to be honest, in mouse models, but slowly but surely we’re starting to find more and more evidence in humans that the gut microbes are very critical. For managing not just blood sugar but body weight and there’s even some evidence that We don’t all respond to food the same I mean I think we need to acknowledge that we’re all just a little bit different and the gut microbes might contribute to some of that Variability and how high your blood sugar goes After you eat the same food as somebody else eats.
[04:25] Shireen: Now, how does diet play a role in really shaping that gut microbiome and how can it be optimized to really benefit individuals who have diabetes?
[04:35] Dr. Corbin: So the bottom line is that we are the ones that feed the gut microbes. So it goes into our mouth, most of it gets absorbed in the small intestine, and that’s where most of the magic happens in the body. But there’s a small percentage, which we control based on our food choices, that ends up making it all the way down the gut to the colon, where the microbes can ferment those foods and perform various functions. So diet is by far the most fundamental way that we as humans impact those gut microbes every single day because we all got to eat at least once or twice a day. So that is how the diet ends up having such a big impact on the gut microbiome.
[05:18] Shireen: And are there certain types of foods that we should be thinking about when it comes to that?
[05:22] Dr. Corbin: Yes, so anything that is highly processed, that doesn’t have any fiber, all those types of foods are very easily absorbable in the small intestine and, and they essentially starve the microbes. But if we want to feed the microbes, then it’s a matter of thinking about four different concepts. One, as I mentioned, is fiber, so your veggies, your whole grains, your whole fruits. Resistant starch, which is a special kind of carbohydrate that is resistant to digestion in the small intestine and percolates down to the colon where the microbes do different beneficial things with that. The third is Whole foods or in our paper, we called it larger particles. And the reason this is believed to be important is because a larger piece of food has less surface area for the digestive enzymes to get to it. So more should make it down to the microbes. And finally, processed foods, so something that has, you know, emulsifiers or has been just completely changed from its original natural form and colors and various things added, all those foods are believed to have a negative impact on the gut microbiome. So the bottom line is a healthy Whole foods diet, which, you know, our moms and dads have told us are good for us for years. The public health authorities and dieticians have. So it’s actually not a new concept, but our study just started to understand why it is so good for us. Via the microbiome.
[07:00] Shireen: Interesting. Now, given that each individual’s gut microbiome is unique, how can we approach personalized dietary recommendations for people with diabetes to really optimize their gut health?
[07:13] Dr. Corbin: Yeah, and as, and you’re bringing back that point that we’re all a little bit different, not just biologically. In our microbiome, but also in what we like to eat, what’s in our culture, what makes us happy. I mean, food shouldn’t be just about, it’s good for you, but you know, bring you a little joy. That’s okay too. So thankfully, these types of things like the fiber and the resistant starch have an impact. No matter what microbes you have. Now, some people may respond more or less, but in general, it should provide a benefit. Now, to get to really personalized nutrition, which, or precision nutrition, which would be, I’m going to evaluate a person and understand their health and understand their microbes, and then prescribe tweaks to their diet so that they optimize the health of the microbes. That’s going to take understanding really exactly what the microbial community does, you know, it’s kind of interesting. We’re not that different from bacteria. They don’t function well in isolation. They depend on each other. They cross feed. So if we just go one-by-one and say there’s more of this microbe or less of this one, you’re not understanding the community in a global level. So there’s new techniques emerging that are going to tell us exactly what the microbes are doing and importantly what they eat, because once we know what they eat, we can figure out what we should eat to specifically change different microbes. So this is all emerging technology that we’re planning on acquiring funding to study in the future.
[08:53] Shireen: Interesting, and any particular foods that we should be thinking about?
[08:58] Dr. Corbin: Yeah. So if I was going to think about not totally, you know, changing what I love about my diet, but think about how do I make some upgrades? How do I think about, have I fed my microbiome today? What can I do today? Or at this meal or snack? To tweak it a little bit to feed the microbes. So I would include more whole grains and less processed grains. More veggies. Resistant starch is the one people kind of look at me funny like, Where do I find that? So if you like hummus, great. It’s in beans, it’s in seeds, sesame seeds, sunflower seeds. In special kinds of grains like quinoa. And also, interestingly, green bananas. Not ripe bananas. And cooled potatoes. So if you’ve cooked the potato but allow it to cool, then the resistant starch forms. So those are some examples of ways to not just add fiber, which we kind of all have some familiarity with, but how to add foods with resistant starch to the diet.
[09:58] Shireen: That’s interesting, and I also want to, as we’re talking about these foods, can you also talk about cultural foods from that same lens?
[10:05] Dr. Corbin: Yeah, so this is what I love about what we did in our study is that we included all kinds of foods. We didn’t intend this to be only plants or only. You know certain types of foods. We just upgraded between one diet and the other and what’s interesting about me You may not have guessed it, but I’m from San Juan Puerto Rico. So I grew up on an island eating, you know Hispanic foods and you know what our mothers were right. The beans are great for us, the plantains the root vegetables. So all cultures have versions of foods that are able to feed those microbes so we can retain those cultural choices that not only are part of our heritage, but frankly, we enjoy and still feed the microbiome.
[10:49] Shireen: You know, we hear about all sorts of different tests that can help us really tailor dietary recommendations. What is your stance on that? And then can you tell us a little bit more about recommendations for individuals with diabetes again?
[11:03] Dr. Corbin: So, with the tests that claim that they could measure your microbiome and tell you what to eat. Unfortunately, I have to say, from my knowledge, the evidence is still really emerging and it comes up to that point I made earlier. It’s that we may know that you have more or less of a particular species of bacteria, but we haven’t cracked the nut per se on understanding what the microbes are doing and exactly what they’re eating. So at this point in time, I say we need a little bit more work. If I was a person with diabetes, what I would do today is think to myself. “If I feed my microbes It could be beneficial for my body weight” because our study showed that when we reprogram the microbes with diet, people actually absorb less calories in part because of an expansion of the microbiome and an increase in hormones that help you feel full. Second, the microbes can also help me manage my blood sugar. So you’re getting a dual benefit of having a microbiome centric thought process when you’re making food choices and the great thing is that the foods that feed the microbes. They feed us less which for most of us is a good thing. Not necessarily for everyone, but in doing so, there are multiple benefits to our health including the fact that the foods the microbes tend to have a lower Impact on our blood sugar because they’re not the refined high sugar types of foods that can fit on occasion. But if we eat those foods all the time, we all know that it won’t be so great for our blood sugar. So thinking about the microbes can help optimize both improving glycemic control and improving body weight for those who need to do both of those things.
[12:53] Shireen: That’s helpful. Now, what are some challenges or obstacles that you see in implementing dietary interventions really to optimize the gut microbiome for diabetes management.
[13:06] Dr. Corbin: So you know, when I was taking care of patients that had either obesity or diabetes or heart disease, to me, the challenge is always the same. We all know that broccoli is healthier than a doughnut. I mean, that’s just intuitive, right? But we still like the doughnut, right? Sometimes. So it’s hard to have. a really restrictive approach to eating, in my opinion. So I think it’s a matter of working with your healthcare provider, your dietician, and looking at which parts of your eating habits could we tweak. And don’t tweak them all at once. Start with one. Go to the next one. And I promise as you make the tweaks, You’ll feel better. You’ll get more motivated to continue making changes because you feel better, the numbers on your glucose monitor look so much better. And so to me, it’s a strategic sort of paced approach. So that the changes can just be incorporated into your life basically forever, you know, with leaving room with somebody’s having a birthday and you want the birthday cake and you don’t want to always have to say no. So it’s really about goal setting. That’s mutual between you and your dietitian or health care provider and taking things in a stepwise approach So that’s not such a shock to your system that all of a sudden your diet’s completely different And also if I could say just one more thing, foods that feed the microbes have a lot of fiber and things that do make it to the colon So if you’ve spent your whole life not eating those foods Eating a ton of them all of a sudden could give you a little bit of a tummy ache or some Gastrointestinal symptoms, so it is good to gradually increase fiber and resistant starch and not just put a whole bunch in at the same time.
[14:52] Shireen: Oh, that’s, that’s definitely good to know. Can you discuss the potential long term health outcomes of optimizing the gut microbiome through diet for people with diabetes? Taking into account what you just mentioned as well, what are some of those long term strategies we can start doing?
[15:08] Dr. Corbin: So I think as far as long term outcomes, there haven’t been enough long term studies that focus specifically on the microbiome, but we have plenty of evidence of long term population studies. With diets that focus on whole foods and higher fiber and things like that. So, you know, the great thing to me about what we did is that it’s in alignment with what’s already believed to be good for public health, what’s already believed by clinicians, dieticians, et cetera, to be beneficial. So. Clearly, there could be other tweaks we do in the future and find more and more things that could be, uh, customized, but for now, it’s a very reasonable approach that aligns with healthcare guidelines and because the nutrients included are known to be better for glycemic control, I think in the long term, it could have a benefit as part of a comprehensive strategy for managing blood sugar to be, you know, a positive way to include one more step in your care plan to improve not just your blood sugar, but your long term health.
[16:11] Shireen: And what I’m hearing you say is also very like, small, consistent changes that help sort of take us there.
[16:18] Dr. Corbin: I think so. I mean, there could very well be some people that actually do better with rip the bandaid off and just jump into the pool head first. And that’s where a dietician is really helpful because we’re going to assess all of that. But just from the patients that I saw and just from myself, I mean, as soon as you tell me I cannot eat something, I want it. It’s hard, right? So it works. You know, in my life to do things gradually and I’ve seen it work in some patients, but really all of it is customizable and for some people making a drastic change could work. So I think being open minded about the road to take that makes sense in your life is really important.
[17:01] Shireen: That’s helpful. Now, your work is described as being transdisciplinary. Could you really explain how collaboration across different fields has contributed to your research and the impact, again, on diabetes?
[17:16] Dr. Corbin: So, transdisciplinary just means across disciplines, and back, you know, many, many decades ago, it was, you could just envision this, right? The lonely scientist in the dark lab, in the corner, pipetting and just trying to figure all this stuff out. by him or herself. And we have just changed so much because now we don’t just look at one gene. We can look at all the genes. We don’t look at one microbe. We can look at all the microbes. And with that, we figured out how integrated and connected things are. So it’s really important to bring in a table of experts. And for us. At Advent Health Translational Research Institute, our expertise is metabolism, nutrition, and human physiology. And in order for us to succeed with doing microbiome work, we needed a partner like Arizona State University, led by Rosie Krasmallick Brown. Because they’re microbial ecologists. So they think about microbes all day long. We think about food and humans all day long. And bringing those together really helps to elevate the quality of the science, elevate the types of questions we’re asking. Because look, nobody knows everything. The first doctor or dietician or scientist that tells you that they know everything, run the other way. Because I’m telling you, I learned something new every single day and often times, I’m learning for people in fields that are complementary to mine and not necessarily in my own field.So I think it’s beneficial for science, and it’s also beneficial for the care of people with diabetes, because we’re able to think bigger, think more creatively, be more innovative, so that we can get, that we can get. Better treatments, better approaches to not just control the blood sugar, but reduce long-term complications and eventually improve health spans. So not just how long you live, but how long you live in a way that you’re healthy and are able to do the things that you enjoy. So it’s such a critical component and it’s not just scientists that need to come together. Clinicians need to be in the room with scientists too, because they’re the ones that see the emerging trends in their patients. I don’t see that anymore. I’m on the science side of the world, so I spend as much time as I can with my clinician colleagues to see what they’re seeing and say, okay, that’s an important trend. How do we study that? Because at the end of the day, doing science is only valuable to me personally, if it’s going to move the needle in the care of people with diabetes and other metabolic disorders.So I just really enjoy bringing all the groups together in the name of making progress.
[19:58] Shireen: That’s helpful. Can you help us understand if someone listening has, you know, diabetes and they’re not sure if their gut health is right where it needs to be, are there signs and symptoms that they can look for? And then can you also provide some guidance around what they can start doing today, some practical advice on what steps they can take?
[20:18] Dr. Corbin: I think as far as signs and symptoms, the only really overt ones that I can think of not being a GI physician is people who may have something like Crohn’s or IBD where there’s some just obvious GI disturbances. But I think in people that don’t have sort of a clinically diagnosed GI disturbance, I don’t think that you’re going to actually have any sign and symptom because, you know, these microbes are super smart and they’ll find a way to survive and do what they need to do. To me, the sign and symptom is that without optimizing them, it’s a little harder to optimize our health.
So if your waistline is not where you’d like it to be, if your blood sugars are not where they need to be. Of course there are pharmacological or medicines that can help with this and exercise and better sleep. But layered on top of that is adding a strategy to use diet to feed the microbes so that by feeding them they help us be healthier.
[21:18] Shireen: And any practical advice on things that folks can start doing today?
[21:22] Dr. Corbin: Yeah. So, you know, I’ve always dreamed of doing science that could go from the lab bench to the kitchen table. And I think this work is just that example. So when you’re making, let’s say a salad. Look at the ingredients. Is there anything on there that you could upgrade to feed your microbes more? Can you add more veggies? Can you throw some beans in there? I just start throwing seeds and beans in my salad and just upgrading it. So as you’re making a food choice, think, is there an alternative instead of the juice? Can I do a whole fruit instead of something that’s prepackaged? Do I have a fresh option that’s accessible to me instead of something that has been so refined that when you look at the label, it’s almost no fiber. Is there an alternative that I’ll still enjoy that has some of the nutrients that will feed the microbes? So to me, it’s really about a mindset of thinking about, did I feed my microbes today? And making those upgrades as you go throughout your day to improve the health of your gut while you’re waiting for us in science and medicine to come up with better biomarkers and better tests. But in the meantime, You have nothing to lose and a lot to gain by making those small changes to the diet to feed the microbes.
[22:41] Shireen: Lovely. What are areas of research that you’re seeing sort of come down the pipeline related to gut microbiome health and diabetes that you’re excited about and what do you see as the future direction in this field?
[22:55] Dr. Corbin: So we have a lot to learn, and I really think it comes down to moving away to asking just who lives in the neighborhood, so what bacteria are there to what’s the community doing? What are they making? What are they secreting that goes into our bloodstream? And how do we then use that as a therapeutic pathway to modulate the microbes, either with diet or with some sort of other precision technology to reprogram the microbes? And how do we continue to refine that so we can determine? Are the gut microbes something we can directly target beyond what we talked about today, which is a very general approach to just feed them and make them happy. But what can we get more detailed and say, we need more of these and more of these because when we do this, there’s a specific outcome we’re looking for. That’s really the next level, all of this, because at the end of the day, the microbes are either doing something specific that causes diabetes or makes it worse. Or, there’s simply a reflection of our health, so we get less healthy, they get less healthy. Or it could be a little bit of both, because, you know, we’re talking back and forth to each other all the time, for sure.
That’s where I think the term gut instinct came from, and they’re in there, and they’re talking to your brain, I promise you. So the functional aspects and how to develop therapies that target them are what really excite me.
[24:21] Shireen: Lovely. And until then, I want to thank you so much for your time, Dr. Corbin. Thank you for coming on and really enlightening us with all the research that is happening in this space. At this point, can you tell our listeners how they can connect with you and learn more about your work?
[24:30] Dr. Corbin: Thank you so much for having me. This was so much fun. And really just Google Karen Corbin and you’ll find all my social media profiles and even some of the articles that we’ve published that may be of interest to you.
[24:48] Shireen: And we will also try to link up some of the things in the show notes so folks have direct access to them. Thank you again, Dr. Corbin for your time.
[24:55] Dr. Corbin: Wonderful. Thank you so much.
[24;57] Shireen: And to our listeners, you know what time it is. Head over to our social media, Facebook, Instagram, find this podcast post and comment below to tell us what is the one thing you can do to improve your diet today. So what is the one thing that you ideally learned from this episode that you’d like to do to really kickstart your gut health? Again, head over to Facebook, Instagram, at Yumlish, find this podcast post, comment below. We’ll continue the conversation there. Thank you again, Dr. Corbin.
[25:23] Dr. Corbin: Thank you.