Our gut helps fight disease. It processes energy for us and boosts our mood. So, having a healthy gut is extremely important — but there’s still a lot we don’t know.
Gut biome tests are a new and exciting technology, but are they the be-all and end-all for dietary decision-making? And are there simpler ways (and tastier ways, perhaps) to tell what’s happening inside our bodies?
In today’s short episode of ZOE Science & Nutrition, Jonathan and Dr. Will ask: What are the signs of an unhealthy gut? And how can we improve our gut health?
Referenced in today’s episode:
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This podcast was produced by Fascinate Productions.
[00:00:00] Jonathan Wolf: Hello, and welcome to ZOE Shorts, the bite-sized podcast where we discuss one topic around science and nutrition. I'm Jonathan. And I'm joined this week by Dr. Will Bulsiewicz.
[00:00:09] Dr. Will Bulsiewicz: Jonathan, our guts help fight disease process energy and boost our mood. So a healthy gut is hugely important, but there's still a lot we don't know, our understanding of the gut microbiomes in its early stages.
[00:00:17] Jonathan Wolf: So is it possible for us to spot the signs of an unhealthy
[00:00:19] Dr. Will Bulsiewicz: Yes it is, but it's not as straightforward as you think. And interestingly, it involves blue poo.
[00:00:26] Jonathan Wolf: Well, blue is my favorite color. My wife often says that if I would buy something that wasn't blue, she'd be really happy about it. And I'm, uh, I'm wearing a green top just because I thought we might be talking about blue today. So let's get into it. So will, when we say a healthy gut, we could mean a lot of different things.
So, What do you mean here?
[00:00:39] Dr. Will Bulsiewicz: First of all, a healthy gut means we have a good balance of microbes, otherwise known as bacteria and yeasts in our gastrointestinal tract. These microbes help our body to take energy from our food to clear toxins and fight viruses, and they help produce the feel-good hormone serotonin.
I mean, this is just a minor glimpse into what they do. They do a lot of great things for us, and secondly, it means that we are not suffering from digestive problems that make eating food difficult for us.
[00:00:56] Jonathan Wolf: And so do you feel that the digestive problems themselves are somehow linked to [00:01:00] this sort of poor situation with the microbes?
[00:01:01] Dr. Will Bulsiewicz: Absolutely. Now to be clear, everyone has occasional digestive symptoms. I mean, particularly if you have one too many pints and you load up on spicy, greasy food. But really what I'm talking about are chronic symptoms that are occurring weekly or even more than that. There are many ways that they could manifest as a clinician.
My first question to the patient is very simple. How do you feel?
[00:01:14] Jonathan Wolf: That's the same question my therapist asked me. So, I like that it's getting straight to the point. So if you're looking for, for centers in this case, and I think you said, look, these are centers where you're having this at least once a week, that's where you're starting to, uh, say this is not just because you ate something that you're not used to, but this is sort of really starting to be something you might talk to a doctor about. So what are the sorts of symptoms that, you know, I or any of the listeners might say, Hey, that's a manifestation of an unhealthy gut?
[00:01:33] Dr. Will Bulsiewicz: Sure. I mean, of course, it could be digestive symptoms. So some of the classic digestive symptoms would be gas, bloating, cramping, abdominal discomfort, diarrhea, and constipation.
But you know, it's important to understand that it also goes beyond the gut. So it could be sleep issues. Or like skin changes such as rashes, sugar cravings, um, unexplained tiredness, or even unexplained mood disorders. I always think about the whole person. You have to think about everything, not just the gut and the gut symptoms.
So it's very important to me to think about these things like mood and brain health, um, where it could potentially manifest with neurologic.
[00:01:58] Jonathan Wolf: And I think a lot of people listening to that will be quite surprised that you [00:02:00] didn't just limit yourself to a set of obvious sort of gut-related symptoms, but you've sort of said, Hey, I mean, you've sort of mentioned every part of the body right, from your mood to your skin, um, you know, to, to fatigue that actually, you can see this in all of these, um, these different places is an interesting and, and sort of shows what a, what a big picture you, you have in mind here.
[00:02:14] Dr. Will Bulsiewicz: Well, I think, you know, to that point, Jonathan, We're getting at the connections of these gut micro microbes to the rest of our body. And so yes, they are very involved with our digestion, but they're involved with all these other aspects of human health, and this is why they can manifest beyond just gut symptoms.
[00:02:27] Jonathan Wolf: And I guess there could be food intolerances too, that these can crop up when the gut is not functioning.
[00:02:31] Dr. Will Bulsiewicz: I mean, what's happening when a person experiences a food intolerance, which is where you consume a food in a normal quantity and then you suffer digestive symptoms afterward, basically what's happening there is that the gut, the gut microbes are not up to the task of processing and digesting that particular food in most cases.
[00:02:42] Jonathan Wolf: Got it.
So you've asked this first question, what's the next thing that you're gonna ask? Our sort of hypothetical gut patient who's coming to...
[00:02:47] Dr. Will Bulsiewicz: The second thing, it may be a bit taboo for a lot of people, but as a gastroenterologist, I've found this to be incredibly important and that's bowel movements.
[00:02:54] Jonathan Wolf: So Will, we've talked about this before, you know, normal people when you first meet them, you don't ask them how often they go to the toilet.
Uh, in fact, it's something that lots of people don't even want to talk about with their family or their partner. So why do you have to ask them this?
[00:03:04] Dr. Will Bulsiewicz: Cardiologists look at blood pressure and heart. As a gastroenterologist. I look at bowel movements, this is my vital sign and I see it as a window into digestive health.
When things aren't working the way they're supposed to within our gut, it's typically gonna manifest in the toilet bowl.
[00:03:16] Jonathan Wolf: And so what kind of things do you talk about with patients Will?
[00:03:18] Dr. Will Bulsiewicz: So the first thing that I look at is rhythm. I feel that the gut is designed to be in rhythm, you know, very similar to the heart.
If you get off rhythm, then things just get disrupted and they don't work the way they're supposed to. So we're supposed to have a cadence, and that means that we should be pooping regularly.
[00:03:30] Jonathan Wolf: That's, that's a real thing.
Uh, as, as a doctor, it's not just something that, you know, maybe we are just all like to have a certain rhythm to, to our life.
Like, we know, we'd like to know what we're having for breakfast and that we're gonna watch this particular show at, at, at 8:00 PM?
[00:03:39] Dr. Will Bulsiewicz: . Oh, I mean the rhythm, you know, is a part that's an innate part of the way that our biology was designed to function. You know, we think about things we've talked about on this show, time-restricted eating, or um, intermittent fasting, and that's just a manifestation of our circadian rhythm.
And what I'm saying here, what I'm here to say today is that you know, our gut has a rhythm too, and it's important that that rhythm be manifested with routine regular bowel movements.
[00:04:03] Jonathan Wolf: I guess, as well as rhythm. There's something about the whole experience being easy, you know, you should feel good, you know, like you are sort of strutting out of the bathroom with a smile on your face.
Not like you've just done, you know, five rounds in, in the boxing ring.
[00:04:17] Dr. Will Bulsiewicz: Certainly not five rounds. And I do think that there's you. Maybe we're not supposed to say this, but you're allowed to feel good. You're allowed to feel well after a good, healthy, um, evacuation, you know? As a medical doctor, that's where I want you to be.
And the bathroom experience really should be positive and relaxed.
[00:04:38] Jonathan Wolf: I do think it's really interesting, you know, so I have, we both have relatively young, uh, kids as, as well as older kids. And, um, you know, we're all too young to remember being toilet trained. Uh, but you sort of see it with your children and you realize, That there's a huge amount of shame wrapped up in this experience, right?
Because it's so important. And I think you do build into that. Therefore, the sense that if you don't do it right, [00:05:00] it's really bad. And so, you know, it's not something I've, I've studied or I, I'd read in new papers about, but you can sort of see how you can end up feeling a lot of. Shame. It's not something you talk about.
If things aren't going quite right, then actually you are sort of failing. And I, I can see how, you know, maybe I'm traumatizing my child, you know, my little girl already, um, by, by the very fact of going through toilet training over the last few years.
[00:05:26] Dr. Will Bulsiewicz: Um, you know, look, I, I, I do think that that's part of this, I think.
Also, we need to be talking more openly about these things. And also I think that the process of toilet training brings up an interesting point, Jonathan because there is a conditioned aspect to this. So the conditions and the circumstances within our life do ultimately affect our ability to go in and have that effortless, satisfying bowel movement that I'm trying to guide people towards.
[00:05:49] Jonathan Wolf: So we've talked a lot about, you know, is it easy and effortless? Tell me what else you, you ask at this point.
[00:05:57] Dr. Will Bulsiewicz: Yeah, so, uh, rhythm is one thing. I'm gonna [00:06:00] also look at things like the form of the stool form, meaning the shape or the way that it visibly appears. And the way that I typically will approach this is using something called the Bristol stool chart, which classifies the poop into specific types based on its shape. So there are seven different categories within the Bristol stool chart.
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[00:06:17] Jonathan Wolf: And we'll put a link in the, in the podcast notes so you can look up your own stool based upon this. Now, Bristol is a city in the UK for those listeners from around the world who, who don't know that, and I don't know how good they feel that now across the world, they're actually most famous for classifying poop.
Uh, however, They are in luck if they would like that to move on because the latest science suggests that there may be a new way to measure a healthy gust that isn't named after Bristol, and that is gut transit time. And gut transit time is how long it takes for food to travel from your mouth... to the other end.
Will, can you tell us a bit more about that?
[00:06:56] Dr. Will Bulsiewicz: ZOE did some exciting research into this, Jonathan, and by [00:07:00] simply eating food that contains this blue, this blue dye coloring, and then tracking how long it takes from when you first eat that food to when it ultimately comes out the other end with a blue bowel movement, the blue poo, as we like to say.
What's interesting about this is like, you know, it's, it's curious, it's, it's cheeky, but also it's science-based. Um, the blue poo we have discovered is correlated with characteristics within your microbiome. We found that transit time can be a better measure, believe it or not, of your gut health than looking at things like your stool consistency or the frequency, or even the Bristol stool scale.
[00:07:37] Jonathan Wolf: And I think that's, that there's something quite fun about something that, that seems fun and light on, on one side. And on the other hand, went into one of the top peer review journals. Uh, and saying that this time it takes, uh, as you said, well, really gives us some additional information, which, which I love.
So, um, what's next?
[00:07:56] Dr. Will Bulsiewicz: So, we've talked about symptoms. How do you feel? We've talked [00:08:00] about looking at your bowel movements, and now the third thing that I really would wanna focus on as a medical doctor is potential conditions that might be associated with an unhealthy gut. When the bacteria in your digestive tract become unbalanced, Jonathan, it can lead to something called dysbiosis.
[00:08:15] Jonathan Wolf: So, Will, dysbiosis is not a word most of us use regularly. You know, Hey honey, I've got some dysbiosis. Has never been said by anyone ever. Could you turn that sort of medical jargon into something, uh, more understandable...
[00:08:30] Dr. Will Bulsiewicz: Well first of all, speak for yourself. My wife and I do speak like that, at home, but.
[00:08:35] Jonathan Wolf: I apologize.
[00:08:37] Dr. Will Bulsiewicz: Um, you know, dysbiosis, what it means is that your microbiome is out of balance. So when you measure it, it would look different than a person who has a healthy gut microbiome. And typically what you would see when there is dysbiosis present, or this loss of balance, is that there's a lower diversity of the different species.
You have less of the. beneficial gut microbes, and unfortunately you have [00:09:00] more of the inflammatory or non-beneficial gut microbes. Some of the effects of dysbiosis could be things like your stomach getting upset after you have food poisoning, and in, in this particular setting, it's temporary and mild. Really what I'm trying to get at here is that there are these serious chronic conditions that may be associated with dysbiosis.
[00:09:17] Jonathan Wolf: And so what, what are you looking for in, um, in this, Will?
[00:09:21] Dr. Will Bulsiewicz: So, you know, much like we, when we were talking about the symptoms, how it can affect the whole body. I, I'm, I'm looking at this through five particular types of conditions that can be manifest, um, as the result of dysbiosis. So, you know, first obviously would be digestive issues.
This is what I do as a gastroenterologist and includes things like irritable bowel syndrome, Crohn's disease, and ulcerative colitis. They're just, just to name a few. But you know, particularly with our work at ZOE, we're looking at metabolic issues. This is through the lens of the gut and things like obesity and diabetes, or high blood pressure and high cholesterol.
They have all been connected back to a loss of balance within the gut microbiome. There's also [00:10:00] the immune-mediated conditions involving the immune system. So really I'm talking about allergic diseases or autoimmune diseases. The fourth category, Jonathan, would be hormonal issues.
So like in women, this would be things like irregular period infertility, endometriosis, polycystic ovary syndrome, or in men, it could be the most dreaded condition that a man could have, or erectile dysfunction. And um, finally the sort of fifth place that we think about medical conditions being the manifestation of dysbiosis is in the brain.
Believe it or not, this is part of the brain-gut connection, and it can include things like mood disorders, but it could also include things like chronic migraines or even Parkinson's disease.
[00:10:41] Jonathan Wolf: And I think, you know, tying back to what you said earlier, this is an enormous list of things, right? Touching every part of your, um, your body and lots of things. I think people, again, might be surprised by when you're talking about things like hormonal changes, um, that I, I think we normally think of as being completely different to this situation.
[00:11:00] Dr. Will Bulsiewicz: Yeah. And, you know, in my mind as I'm approaching this as a clinician, what I'm doing is I'm sitting there and I'm looking at this person and they're telling me how they feel. They're telling me about their bowel movements, and then I'm thinking about like, is there a pattern within their chronic health history that would help for me to, uh, explain what's going on with them?
And, you know, so I'm not looking for one thing. I'm looking for the emergence of multiple of these different diagnoses that I just mentioned. And when you see that pattern, then you know that, you know, gut is a part of the issue here.
[00:11:28] Jonathan Wolf: So, so far we've talked about three ways that you might investigate signs of an unhealthy gut.
You've got symptoms, you've got the bowel movements, you've got the related medical conditions. But one thing you haven't mentioned is gut microbiome testing.
[00:11:43] Dr. Will Bulsiewicz: I feel that the testing needs to be validated. So for us to have confidence and use these tests within a clinical setting where we are helping to guide patients to better results, we need research that validates.
And proves [00:12:00] that using this test and the information that we get back from it, we can get to that place of improving a person's health. So almost all of the, the problem, Jonathan, is that almost all of the microbiome tests that are currently available, they, they haven't done this. They need to publish papers showing us that they work.
[00:12:15] Jonathan Wolf: Now, a lot of listeners will be a bit surprised about that because ZOE is hosting this podcast and is part of ZOE's testing at the beginning of the personalized program. We do our unique microbiome tests. So, what are you saying?
[00:12:29] Dr. Will Bulsiewicz: So obviously I believe in ZOE and um, the issue is that ZOE is not just a microbiome test.
And I think it's very important for people to understand that ZOE is far more dynamic in terms of what it's being offered and it goes far beyond just microbiome testing and isolation. I mean, you know, we're looking at their blood sugar response, their blood fat response. We're looking at their complete dietary picture, and I think its most fair for us to say that microbiome testing is still in its early stages, and we don't know enough as of today to be able to give strong advice based upon. The microbiome alone.
[00:13:07] Jonathan Wolf: Well, I think I'm, I'm glad to hear you. You feel it has someplace here and, as we've been looking at this, you know, at ZOE, we've sort of concluded that we don't feel comfortable that just using a microbiome test on its own is enough to advise you on what to eat.
And so I think this is, uh, you know, it's a key message to always recognize that you can hear about this incredibly exciting new thing, sort of on the edge of science. And then when you're trying to come down and say, well, you know, I wanna know what I should eat, or I want to know what my mother should eat, my wife should eat, um, then you need to say, okay, what's all the best evidence together now, Will.
[00:13:54] Dr. Will Bulsiewicz: Thinking about this as a sort of technology company, as a doctor, is it unusual to say, Hey, there's just not like this one test that I would use and give me all the answers.
I mean, that's not unusual at all, to be honest with you. I, I think it's important for people to understand that as a doctor [00:14:00] when we attack, You know, these problems and try to guide our patients to a better place.
It's about integrating all of the available information, whether it's the microbiome or blood sugar, or food intolerances. The point here, Jonathan, is that when you see this bigger picture and you integrate more information, you can get more clarity in terms of what defines the person.
[00:14:21] Jonathan Wolf: And so, Will, what if I've listened to all of this and I think, you know what, I think I might have an unhealthy gut based upon, you know, I'm sort of ticking off the things as you described them. What should they do?
[00:14:32] Dr. Will Bulsiewicz: Well, to be honest with you, even for the listeners who are sitting there saying, look, I feel like I'm pretty good.
My gut's healthy. I, I would say to you, look, this is so important no matter who you are, we all should start where we are today and strive towards an even healthier gut because this is so essential to human health. And for all of these people who are trying to take that step towards a healthier gut, the most important thing is to make the right diet and lifestyle choices that can lead to better health.
This can include things like managing our stress [00:15:00] levels, uh, improving the quality of our sleep. Believe not simple things like eating slower, drinking more water, eating a varied diet that's high in fiber and grains, and leafy vegetables, and cutting back on all highly processed foods can be another step that people can take.
[00:15:15] Jonathan Wolf: And if I do all of those things, do you think I would expect to see a change in my gut health if I, I was exhibiting some of the things that you'd been just talking about earlier?
[00:15:23] Dr. Will Bulsiewicz: Absolutely. I mean, remember that you know, it kind of comes back to this basic first question, which is how do you feel you should feel.
When your gut is becoming more healthy, you should feel better. You should see an improvement in food intolerances. You should have better bowel movements and um, over the long run you may be able to. Improve your health status in terms of reversing or improving or reducing your risk of these chronic medical conditions that we've been talking about.
[00:15:48] Jonathan Wolf: And one of the things I always love, whether it's you talking about this or Tim or anyone else, is there's a huge amount of positivity because this is an area where you're always saying, you know what? There's a power for us to make changes that can improve our health. And I think most of the time, We feel we're sort of stuck in a one-way, uh, deterioration.
So like it's all like, ah, you know, my body was great when I was 21 and now it's just getting worse and worse. Or, um, you know, there's nothing you can do. All you'll do is just sort of hold back the tide. And so I think what's, what's great listening to this is you're saying to lots of people you can improve your gut health so that it's a lot better in a year than it has been, you know, maybe for decades, maybe forever. Is that, yeah? Is that true?
[00:16:34] Dr. Will Bulsiewicz: Yeah. I mean, Jonathan, you're mentioning a 21-year-old. I'm, I'm twice the age of a 21-year-old at this point in my life, and I think I have twice as much health as I did when I was 21 years old.
And that's because of changes that I've made to my diet and lifestyle through the years that have allowed me to get to a better place. And I think it's a message of empowerment here, which is that you are not a genetically pre-programmed list of medical conditions and health-related problems.
That you have the power through your [00:17:00] choices to make small changes that can yield massive results in terms of your health. And that, to me is the important message and it's really exciting, and that's a part of what we're doing.
[00:17:08] Jonathan Wolf: And, and maybe just, to finish up, I'd love to, to go back to the neon blue muffins that we talked about earlier when we were talking about measuring your gut transit time.
Um, because this is something that anyone listening to this podcast can do at home. If you wanted to, to find out more, there's, uh, a link. We'll put it in the show notes. But it's at joinzoe.com/bluepoop. Um, and will, is this something that you tried with your family?
We did, yeah. So, um, at the time we had two kids. We now have three. Um, I didn't give blue poop to my, you know, seven-month-old who's drinking bottles. But we did it and it was, you know, it's quite fascinating. It's quite fascinating just to kind of. Get the results, but also when you dig into the paper that was published in the journal Gut, which by the way, uh, speaking as a gastroenterologist, this is the top European gastroenterology Journal.
Uh, when you dig into the ZOE uh, paper on this topic, it's fascinating to discover the connections that exist between your gut transit time using the blue poop method and your microbiome, and even potentially your cardiovascular risk. So it's. You get a lot of bang for your buck by just eating a couple of muffins.
Absolutely. And um, I did this, I enjoyed doing it. Um, but my, uh, my kids enjoyed doing it as well. Cause we got the whole kitchen blue and then interestingly we were all fascinated, you know, for the next 24 to 48 hours about, you know, when we were gonna find the blue coming out the other side.
And, therefore, what this was going to say, as always, I think one of the interesting things is you don't know your transit. So you might go regularly every 24 hours, but you don't know how long it takes from the point that you eat to when it comes out the other side. It might be that it's taking you two or three days.
So I, I do think it's just this, it's, you know, incredibly cheap, do it yourself, experiment. Um, and there's something that's always so interesting about understanding more about your own [00:19:00] biology and also realizing that there's this huge variation. People. And so once again, this idea that we're all just the same, you know, it's just a little micro example of how that isn't true.
[00:19:10] Dr. Will Bulsiewicz: Yeah. I, I think just to riff off of that real quick, Jonathan, um, first of all, people who do the blue poop challenge, which you can do at any time, uh, you can input your results and actually will provide you, receive feedback from, uh, our website that allows you to understand even further beyond just like how much time it was.
And I, I, and I think one of the other things that I would say real quick is that a common question related to this is, well, why don't I just eat some corn? Or, why don't I just, you know, um, drink some beet juice and see when that comes out? And the answer to the question is that those particular tools haven't been clinically validated for this purpose.
So coming back to the idea of validating our research and publishing it in journals and showing that it works with the blue poo method, we have done that. We have shown that these [00:20:00] correlations are real and they do exist, and that's, that's the reason why you opt for this technique as opposed to just, you know, drinking some beet juice.
[00:20:06] Jonathan Wolf: Amazing.
Well, Will, I think we learned a little bit today about an unhealthy gut, uh, which was a lot of fun. If you have listened to this and you'd like to try ZOE's personalized nutrition program to discover what's going on in your microbiome and improve your health, you can get 10% off by going to joinzoe.com/podcast.
I'm Jonathan Wolf.
[00:20:27] Dr. Will Bulsiewicz: And I'm Dr. Will B.