Simple ways to improve gut health | Dr. Karan Rajan

25:28And then those bacteria themselves are somehow also managing our immune system. So there's this sort of complex interplay. And maybe I want to come back to that thing you mentioned early on about our early life? Because I understand that there's a lot of research suggesting that one of the really important things that's going on inside children in the first couple of years is actually sort of developing their microbiome and managing it and a sort of two-way system. I mean, in terms of microbiome, building it and building it the right way as though it were a neatly curated bonsai tree, I think there are certain things we can do to guide it in the right way, but it's not always possible for everyone.

26:10For example, we generally have to assume these days that when you're a fetus, as far as we're aware, essentially that fetus is sterile in terms of there is no existing microbiome and it's populated throughout life. And there are certain paths that microbiome can take. So for example, vaginal birth versus cesarean section, there'll be a different set of microbes either way. So through the mother's vaginal canal, there'll be some microbes that come onto the skin, onto the mouth, which is then swallowed. And then that populates it. And C-section, there'll be bacteria from the mother's skin potentially, or from the surgeon himself touching, surgeon themselves touching the baby.

26:49And then the next stage would be interacting with the environment, whether the child is breastfed. So the bacteria from the breast milk, or if it's via formula or infant formula or something like that, whether the child at an early stage is in an urban or non-urban environment, exposure to animals at a young age, whether it's an only child or it's the youngest child or the eldest child, that also has a role to play. As an eldest child, I want to know what's best because I know I have a younger brother and a younger sister. They would each argue that being the youngest or the middle is best. So I'm going to put you on the spot now and find out what is the best.

27:27So based on some of the research that's been done on this allergy risk and autoimmune disease risk, it suggests that the youngest child is probably the best, as it were, in terms of having the lowest risk for these things. Because it's getting these infections from their older siblings and interactions from these people. There's more diversity in their environment because the elders just had themselves. That's fascinating. So it's another example where it's the exact opposite of the way that I understand things when I grew up, which is you want to keep the environment completely clean. You're basically saying the youngest child is surrounded by all these older children who are like bringing in dirt and mess.

28:07And actually, they are therefore having less issues than the eldest child who is sort of wrapped up in cotton wool by their adoring mom and dad. Yeah, supposedly. And I think actually you mentioned there about the sort of sterile environment and this hygiene hypothesis. And that's one of the things which we've changed in terms of scientific community. We've changed our idea on a lot over the last few decades. There was this idea that hygiene hypothesis, that the sterile environments are leading to increased rates of allergies, etc. But that hygiene hypothesis is not quite right. And it's more called almost the new friends hypothesis.

28:43You don't want a super sterile environment. You also don't want to introduce unnecessary pathogens to children. So, you know, if a child drops a chocolate bar on a, you know, dog poo, you don't want them to consume that chocolate because you think, oh, yes, low-grade bacteria is good. That's no, pathogenic bacteria will always be pathogenic no matter how strong your immune system. All it suggests is that it's okay for kids to play in the mud and then, you know, make sure they're washed afterwards. Wash your hands, get your vaccines, all the basic things, but a little bit of dirty in the environment and diversity isn't a bad thing.

29:19And it probably could be a good thing. That's fascinating. I want to sort of bring us back, I guess, to the place we started was this amazing statistic of like 40 % of people having these gastrointestinal issues. And I understand that IBS is sort of the most common disorder within that group. Could you maybe help us to understand simply what it is, what's going on, and maybe what the difference is between that and some of the other sort of diseases that you describe, like Crohn's or something like that? The thing is with IBS, irritable bowel syndrome, we don't really understand in most of the cases why it happens.

29:59There are some cases of IBS which can be secondary to things we do to the body. For example, you can get post-infectious IBS. If you have a particularly bad bout of gastroenteritis or stomach bug or food poisoning, you can actually develop some sort of irritable bowel syndrome, which is not the sort of primary cause, but that is a thing. If someone's undergoing chemotherapy after bowel cancer surgery or radiotherapy, you can get some sort of pseudo irritable bowel syndrome. And there are lots of diseases which mimic IBS, but there's so many different subtypes of IBS. You can run constipated, you can run more loose, you can run mixed.

30:38And we don't have one specific cause. It's very likely that lifestyle factors maybe have a role to play to at least worsen symptoms. The microbiome and the immune system have a role to play, genetics, but we haven't put it all together. We have different parts of the puzzle, but we haven't put it all together. And really, it's, you know, dissimilar to other things like, for example, autoimmune conditions, which, again, the similarities probably stop at the microbiome and the immune system, which is heavily involved in autoimmune diseases like Crohn's or ulcerative colitis. But those are lifelong, and there are no real cures, as far as we know, for many of these things, IBS included, Crohn's, ulcerative colitis.

31:19We have medications, surgery, and management options which can limit symptoms, but there's no cure. Even for bowel cancer, we remove the cancer macroscopically, and then the patients might have chemotherapy, radiotherapy, and they have surveillance. But it's not an instant cure once we remove bowel cancer. There's a period of observation where we need to make sure there's no disease recurrence. And that's the problem with the gut. Because we know so little, it's hard to have definitive cures like in many other conditions. It sounds like you're saying, though, that actually our understanding of what is going on inside the gut is not as well developed as in many other systems.

31:55I mean, we know a lot about the gut. For example, colorectal cancer, the treatments for colorectal cancer have improved dramatically over the decades. And for all intents and purposes, you know, in most cases, like it was maybe decades ago, it's not really a death sentence. We have amazing technology, diagnostics, and operative and other management options to deal with it. And even now we've got novel monoclonal antibody treatments for various things which we didn't have years ago. For example, someone could essentially be virtually asymptomatic with Crohn's or ulcerative colitis in specific cases just using these monoclonal next generation antibody treatments.

32:36What is the difference between irritable bowel syndrome, IBS, and Crohn's? And then can you help us understand for a minute what you're describing, which sounds very exciting? So irritable bowel syndrome is different to inflammatory bowel disease, where one is autoimmune and one is, we think it's a gut-brain-driven functional disorder. Inflammatory bowel disease is not a functional disorder. It's an autoimmune disease where there is the body's immune system is attacking its own cells. Its own self, it doesn't recognize self as self, sees it as foreign and attacks it. And that inflammation can cause symptoms like bleeding from the rectum, pain, bloating.

33:14It can increase that chronic inflammation, can increase the risk of bowel cancers as well. In many of these cases of ulcerative colitis and Crohn's disease. And really these novel treatments, I mentioned these monoclonal antibody treatments, they're essentially immunosuppressants, which suppresses the immune system and thus would help to suppress and manage the symptoms that would be experienced by that inflammation. Anti-inflammatory treatments, essentially, which are fantastic. And that's just a testament to how much we've progressed in the gut space. But equally, I see the gut space as this sort of reverse Dunning-Kruger effect, where the more we know, the more we realize we really don't know.

33:54Because it's within the last couple of decades, people, I think a lot of it in Holland, have pioneered these fecal microbiota transplant therapies, you know, poo transplants, and seen remissions in cases of gut disorders. You know, clostridium difficile infection, clostridium difficile is a bacteria, and it's commonly C. diff. Diarrhea happens after prolonged antibiotic use. And that's awful. You know, that can be life-threatening. And, you know, someone pioneered a treatment where you get poo from a healthy person, put it into the gut of an unhealthy person with this disease, and you see a disease remission.

34:29And, you know, this poo transplant is pretty widespread, even in the UK. And that's fascinating for me to think that, wow, you know, such a DIY type therapy actually has some potent effects. So it shows me that we're rapidly progressing in our understanding. But also, wow, you know, it's like an abyss. There's so much to uncover. I was really struck as you mentioned the fact that these inflammatory bowel diseases is autoimmune disease where your body is attacking yourself. because we had a fascinating podcast recently about childhood allergies and the growth in peanut allergies, where our guest was explaining that now about one in 10 children in the US and the UK have a peanut allergy.

35:09And 50 years ago, it was like 1%. So there's been this enormous increase in this situation, which is an allergy, which is again, as I understood it, like your own body basically attacking this thing that is actually healthy food and thinking like it's a pathogen, is there an increase also in these sorts of inflammatory bowel diseases in comparison to 50 years ago? Is that the same as it used to be or has that increased also? Yeah, I mean, as far as the data concerns, increase in irritable bowel syndrome, increase in other digestive conditions, including inflammatory bowel disease, even colorectal cancers as well.

35:44And as to why that is, you know, I don't think there is one singular answer. There may be something to do with the diet, almost certainly. It's changed significantly, whether there's some effect there. Climate and environment, that is certainly a factor as well. And you could also argue that our lifestyles and behaviors have changed significantly from how we sleep to how we interact with other people. We have far more isolated lives these days than maybe 50 years ago, where maybe you could say we're a bit more asocial now, particularly post-pandemic. There's been increasing isolation. So there's a number of factors, and they all probably have a role to play.

36:23Epigenetic factors as well. So not just genetic, but environmentally, how the environment has changed our genetics. So I don't really know is the honest answer. And it's an evolving space as we understand why it's all changing. Because if you look at certain populations around the world, and if you compare yourself and myself, who are living in the UK, the Western world, and you compare our gut microbiota and, you know, will be relatively healthy guts. And you compare them to the most similar we can find to our ancestors maybe a few hundred years ago who didn't have access to the vices of modern life.

37:00And something like that would be the hunter-gatherers in, you know, sub-Saharan Africa, the Tanzania, for example, the Hadza tribe. Their microbiome have species of bacteria that are non-existent in other populations, Italy, UK, US. Why? So we've got extinction of certain bacteria that are essentially endangered and only found in some of these hunter-gatherer tribes or more isolated tribes. Why? So clearly the vices of modern life have a role to play. Before we move on to what can we do about this, I just want to pick on one other thing you said, because I think you mentioned a couple of times that we're actually seeing a rise in bowel cancer cases.

37:39And this came up on a podcast specifically, but I'm fascinated in, you know, if that's true, is this what you're seeing? Yeah, I mean, it's certainly more visible, and certainly in younger people. And you could argue, is it a true increase in actual prevalence? Or are we just picking it up more because of better diagnostics? You know, that's the real answer there. And it might be both. It might be that we are seeing an increase because of changing lifestyle factors, lower fiber, which is a risk factor for bowel cancer, etc. But also because we are more health conscious in 2024 than we were in 1924, for example.

38:21And we have high resolution CT scans, we've got access to these services, certainly in the Western world, far easier. You know, I think even 20 years ago, 30 years ago, when someone comes to hospital with abdominal pain, as opposed to now in 2024, where we would get a CT scan within a couple of hours of that patient entering the hospital, and we could pick up something serious. Just decades ago, it was more a clinical diagnosis. It could be this, and they'd be sent home potentially with a diagnosis of IBS without having a scan. And that could have been IBS masquerading as a bowel cancer potentially.

38:59So it's that increase in diagnostics and clinical efficacy maybe now. But also, yes, there may be an increased actual prevalence as well. It's hard to unpick both. You're saying we'd probably catch a lot more than we would have done 20 or 30 years ago because we've got better technology for actually picking this up. And bowel cancer screening programs and all of these things and people are engaging with them a lot more. So certainly, yeah, pickup rate is much higher, I think. Well, our listeners have been very patient while we sort of talk about what's going on. I definitely want to transition now to something I know you talk a lot about in all your different social media, which is when you're thinking about advising people about what they can do to make their guts happy, what do you say?

39:38And maybe we should start with food, which obviously we spend a lot of time talking about in Zoe and I'd love to discuss a bit with you. but then I'd love to discuss some of the other things that you talk about as well. Yeah, I think it does start with the food, a lot of the at least easy options that someone can make a change from right now, listening to this podcast from tomorrow, from today even, making that change. And we know the gut microbiome is quite adaptable. It bounces back relatively well and it's very responsive to change. So even within 24 hours of eating a certain food, you can begin to see some changes in the microbiome.

40:09So, you know, if you look at most of the, you know, literature that's out there, the meta-analyses and the systematic reviews, when it comes to eating for better gut health, it's nothing very complicated. If you break it down into, you know, we talk about fiber and prebiotics, they're essentially the fertilizer for the bacteria, allowing them to thrive. So, you know, plant-based foods. Now, it doesn't mean you need to have a plant-based diet full stop and cut out every single piece of meat or fish. That's, you know, not the case. You can have a perfectly thriving microbiome with meat. But the majority of the diet, if it is plant-based, that's good.

40:45And I think even a lot of the ZOE data, which published a few years back, suggested that magic number to be around 30 grams of fiber a day. And I think getting not just that target in mind as that number, but also an abundance of variety as well. And a lot of the studies suggest that the diversity comes from the colors. because the colors are linked to varying levels of polyphenols, which are antioxidants, natural phytonutrients, plant chemicals, which provide this sort of anti-cancer, anti-inflammation effect. That's what antioxidants and polyphenols are. And that helps your gut ultimately. And all of these fiber-rich foods, apart from providing various nutrients, vitamin C, vitamin A, et cetera, also provides that basics of the fiber, the solubles and insoluble fibers, which we can't deal with with our normal digestive enzymes, but the bacteria which we host in our colon, their enzymes, the bacteria enzymes can deal with that and then ferment those fibers which we can't process to then churn out other beneficial nutrients like vitamin K, B12, and much, much more.

41:51And a lot of these chemicals, particularly things like butyric acid, butyric acid is a short-chain fatty acid, which is very beneficial for the gut lining and the gut health in general. So all of these sort of basic things, colorful foods, diversity, and fiber, those are the kind of very, very basics. And all of that, interestingly, is basically about feeding your microbes to then support your health. So it's interesting that all of the things you've described so far, when you're saying, how do I have a healthy gut and hopefully reduce my risk of these symptoms, it's interesting you're very focused, in fact, on supporting your microbiome.

42:26Is that a fair playback? Yeah. I think, you know, more so than worrying about, adding more good stuff to your garden and adding more flowers to your garden, that's not sustainable unless you actually tend to the existing wildlife and flora and fauna that exist right there right now. And that's the best strategy you can do. So if you've planted all of these wonderful flowers, you need to take care of those instead of just adding more good flowers and forgetting to water the ones that are there. I love to hear you talk like this because I am reminded, as I said, about 25 years ago in my experience, seeing quite a lot of doctors in the UK with the symptoms I have and just really no thinking at all about this idea that you have the microbiome, that you need to feed it.

43:06And what's interesting is that I've been on a long journey with my own health and my symptoms got much better through my 20s and 30s and interestingly were triggered by an illness at the very beginning, which is something you mentioned could possibly happen. But one of the things I've been really struck is since I started Zoe and started working with all these different nutritional scientists, you know, my diet has changed a great deal and it's made an immense difference to how I feel. And I never would have believed that that was possible. So I find there's something really wonderful that, you know, there are doctors now sort of talking about this.

43:41I do want to ask a bit, because I think you were just switching there to contrast, I think, eating food with sort of probiotic supplements, right? Eating something which says it has bacteria in it. And I want to come back to the question right at the very beginning. What are your thoughts on probiotic supplements? So I've prescribed probiotics to patients, limited over my career, but these are medical-grade probiotics, have specific strains, lactobacillus usually, which is one of the most highly studied strains of bacteria when it comes to probiotic research. And they have the right number of colony-forming units, So the right concentration, dosage, etc.

44:20And again, when we prescribe them, we don't prescribe them with the absolute guarantee and belligerent confidence that they will absolutely work. They might work for a specific subset of people with conditions. So certain infection-associated, you know, antibiotic-associated infections, maybe certain subtypes of IBS, and certain post-bowel cancer or bowel surgery states, they may have some effect. We don't really know, but there is some evidence they may have some effect. So when you then contrast that with consumer-grade probiotics that's available for the public in your local supermarket, there is no way to guarantee that has an effect for a multiple number of reasons.

45:08One being that our microbiomes are so unique, as unique or more unique than our fingerprints. So how can we expect an over-the-counter, one-size-fits-all supplement to work for every single person? That's one argument. The second argument is in the UK and in the US as well, these are regulated as foods and supplements, not medicines. They don't have to go through the rigorous medical testing and trial testing. So actually, these probiotic supplements, juices and drinks, don't have to actually back up any evidence that they purportedly claim in their bottles. Do they actually have live strains of any of these?

45:44Do they have the right number of units? They can claim all these wonderful things like immune boosting and claritin focus. None of that has to be backed up at all. That's rather depressing. It's very depressing. And what's even more worrying is that I was of the opinion that, you know what, it's harmless. It probably won't work, but it's harmless. So if you want to take it, you're just wasting money, go ahead. But actually, I was wrong. It's not necessarily harmless because there is actually, you know, a few research papers out there suggesting that if you add in all these probiotics, if they are alive, what if they overcrowd existing good ones?

46:18if they do end up colonizing? What if they end up colonizing in the wrong place and causing small intestinal bacterial overgrowth? What if they do cause more harm? What if they contain contaminants? So actually, more so than money, there is published evidence suggesting there could be a risk as well. And one final thing I will just say on that as well, there was one interesting study I read which suggested that a lot of these bacterial strains put into so-called probiotic supplements are genetically engineered. and they could be harmful in a way that it contributes to antibiotic resistance because these are, again, genetically modified and bacteria transfer their genetic information via horizontal transfer.

47:01That's one way, apart from mutating. So they could transfer some of the genetically modified genes to bacteria which already are inside us, that we host, could increase the risk of antibiotic resistance. That's definitely a concern. I can tell you're definitely not very keen on people going down to the local grocery store and popping a probiotic. I wouldn't be. I think I'm optimistic in that we will get to that point in science where actually that's a viable option, where we have tailored probiotics or even generic probiotics, which actually do work. But I don't think they're in the science where we can actually say, just like we recommend vitamin D in winter months.

47:43Actually, yeah, we recommend probiotics for general health. I think we could get there in the next few years, maybe. But right now, I don't think it's worth it because there are so many other low-hanging fruits. I think there have been two things that have been quite eye-opening for me. The first is because we can now do this sort of shotgun sequencing of the microbiome, so we can actually understand the individual microbes that are inside your gut, and then from that, figure out which are really the good ones. And I described that we now have this panel of sort of 50 microbes that we've identified as good microbes.

48:14What's interesting is these probiotics you buy, they don't have a single one of those 50 good microbes, which was shocking to me. And what I've understood now is it's really hard to grow the microbes that are inside your gut because they like to live in a place with like no air and they're managed by your immune system. Like it's a very special environment. Whereas the probiotics that you can easily grow and therefore sell, like, well, they just live in the air. And so you end up with these things that tend to, you know, colonize a yogurt well, but it's not necessarily the thing that's best for your gut.

48:44And the other thing that was really interesting to me is that when I broke my toe, I called up two scientists and doctors who are associated with Zoe, Tim Spector and Will Bolsiewicz. And basically after all of this, they said, Will said, well, there's one probiotic that I think in this particular situation you might try, which is actually yeast. And Tim was like, oh, I actually wouldn't take any. I would just go all out on fermented food. And I was fascinated that the cutting edge insight was so far away from what I had started with, which is this assumption that, well, you know, just pop these probiotics.

49:17So there is like a really big gap, I think, between, I guess, what's been sold today and it seems to be where the scientific evidence is today. Yeah, I think so. And even when we recommend fermented foods, that's with the best intention of saying, listen, they contain probiotics. They also may be prone to not surviving the hostile environment of your stomach acids and digestive enzymes. and they might also not take root and colonize, but they're cheaper. It's far more safe in terms of risk profile. There is a chance they can take root, but also more than that, they have a host of other benefits beyond just the probiotic nature.

49:54So yogurts and kimchi, for example, you're eating it for the protein or the fiber or the other spices, not just the probiotic value. When you buy a probiotic, there's no other value in the probiotic. There's no extra protein. There's no other vitamins or minerals. it's just a probiotic. But with food, you get all these other benefits as well. Now, Karen, I can't wrap up without picking up on something you've talked about a bit, which is foods that boost your mental health. And I know that there are a bunch of foods that say things like serotonin boosting on the label. What's your view about that?

50:28I never really understood that. Actually, my first instance with this sort of food mood thing was, you know, they say that cheese gives you nightmares and things like that. And I never really understood where's this coming from. And then, or turkey makes you sleepy. And I looked into it. And then you look at all these generic websites they talk about, it's usually news headlines. And they talk about, you know, the tryptophan and that causes the drowsiness and this and that. But often whatever's broken down in our guts, a lot of these molecules cannot cross the blood-brain barrier and have brain impacts.

51:02So really, when food affects mood, I think it has an indirect role potentially. So if you eat more fiber and your gut microbes are healthier, they may produce metabolites and byproducts, which may influence your mood, but also not accounting for the fact that if you're eating more fiber, you'll probably poo better and you'll feel better as well. There's loads of indirect links, but directly, I would be very hesitant to say there's a singular food that can either improve or ruin your mood. With possibly the exception of alcohol that can do both in a short period of time. And then wipe out your microbes.

51:41Yeah, exactly. Now, we talked a lot about digestion. I feel we should sort of come to the end of the line because I know that this is important for everyone who's a gastroenterologist or a surgeon. What's the criteria for an excellent daily poo? I like to refer to it as the Goldilocks zone. Everyone's different. So if you're outside the sort of threshold of three times a week to three times a day, that spectrum, you're probably running constipated. But your bowels are more than just frequency and number. It's also about how you feel afterwards, how you feel before, how you feel during. Are you straining?

52:21How it looks? How it smells? How it feels? there's a number of variables here but essentially if you have some sort of regularity and you know even for example you're going once a day and you feel incredible after you've gone and it's a huge evacuation that even could be that you're constipated you could well be constipated going once a day yeah it's a fallacy to think that you can't be constipated so there are things though that you can do to ensure that you have the highest chance of having a good motion You know, beyond hydration and eating more fiber, there are things you can do in terms of, I mentioned at the start of this chat we had, that the gut is intrinsically linked to our circadian rhythm, that biological clock.

53:05And there are certain hormones which are released at certain times which make us have the urge to go in the morning. So if you keep going to the toilet for a number two every day at seven o 'clock in the morning, your body releases hormones and enzymes and cues your digestive system to think we need to make sure this happens at 7 a.m. every single day. So the day you're jet lagged or you're traveling and you delay that by a few hours, that can disrupt everything, your whole digestive system and your appetite and beyond. So actually keeping a rhythm, just like your sleep-wake cycle, trying to keep the sleep-wake times aligned, trying to keep your bowel motion timing aligned as well.

53:43When you have the urge, that is a cue. That's a signal to go, okay, go as soon as you can once you feel that urge. Once you feel the walls of the rectum stretching, that's a cue. You need to get there now. Because if you ignore the cue, in the stool, the feces actually retro-traverses inside your colon a little bit more. It goes backwards. It reverse parks slightly. And once it's in there, you miss the signal and then you might have to strain, which then, you know, signals this kind of chronic constipation cycle. You know, there's things which you can do in terms of your physical maneuvers and habits in the toilets, trying to get your knees higher than your hips, maybe even leaning forwards, putting your, you know, your feet on your tiptoes to get more of that angle.

54:29There's so many things you can do and even not spending an overly large amount of time on the toilet as well and straining. So it's really, you know, there are certain habits we can suggest, but again, everyone is wired and plumbed so differently. It's difficult to give sweeping recommendations for every single disease state and person. Do you know someone who gets frequent gut issues, cramps, indigestion, or can't eat certain foods? Why not share this episode with them right now? Empower them to feel better with the latest science-backed information. I'm sure they'll thank you. But it sounds like saying it does matter having like a regular movement, ideally sort of, you know, at the same time going when you want to go like this matters is going to affect sort of everything that is upstream if that isn't working right?

55:24Yeah, I think really, you know, we're governed by so many hormones and clocks and rhythms, our bodies basically that suggests they crave routine, just like sleep, just like food, mood, everything. It's just routine. You know, when you're in a good routine, you feel good because everything runs on autopilot. And once there's even a slight variation or disruption of that routine, you almost feel, you know, ripped out of time and space almost. And it's the same thing with bowels. You know, even if you're away from your usual toilet, psychologically, we know the gut and brain is linked. That can have a huge impact.

55:57If you're in a different country and you don't use to your own throne, that can be chaos. I love that. And I love that you're talking about it because I think this is one of those things where there's, particularly like in the Anglo-Saxon world, like, you know, America or the UK, people don't like to talk about it. I'm always really struck that, you know, if you go to Germany, they have a completely different toilet bowl where afterwards you can like really examine what's happened. Whereas in the States or the UK, it's all designed to like hide it away completely as fast as possible, which tells you there's a very different like mindset around this activity.

56:27I think so. There are inbuilt inherent cultural taboos. We're obsessed with, you know, deodorizing the toilets with the potpourris. We don't like to talk about the smells. Interestingly, in Japan, they have toilets that have white noise in public toilets because they don't want people to be ashamed of the noises they make when they're in the toilet. So, you know, for those shy poopers, for shy pooping syndrome, they've got constant flushing white noise to drown that out. And I think that is a wonderful cultural example of how taboo toilet habits are. It's brilliant. And I have been to Japan and they have these extraordinary toilets.

57:04We should do a whole mini episode on that. but I know I'm running out of time. So my producer said I had to make sure I asked this last question, given it was so popular. And you picked it up a little bit in the short answer questions at the very beginning. Should we be holding in our farts? I mean, ideally, no, because it's a gas that needs to escape and it'll just prove very uncomfortable and it can worsen any bloating that you might have. So there's no harm to your life if you're holding in your farts, but it'll be very uncomfortable. And I think the more you hold in your farts, it's essentially contributing to this taboo we have that it's wrong.

57:44I'm not saying that if you're in a busy meeting that you need to let one rip right there in front of everyone. But it's something which we need to take more account of. You know, we look after our physical health in so many ways. It'd be a shame not to pay heed to these sort of more, you know, the ugly duckling of the health world, the farts and the poos. I can see you feel, this is part of the light feeling that this whole thing is just not as glamorous as the heart surgeon is that. This is the fight back. I'm trying to, you know, sort of revolution in poo. I love it. I think we are partly doing that as well.

58:19I'm going to try and do a quick summary if that's right. And then will you just correct me if I get anything wrong? So we started with this brilliant idea that digestion starts in the brain. And then you told us we are a donut, both of which I love and I'm going to stick in my mind. And that's because actually, like I got, it's sort of on the outside, even though it's inside us, that it's much more than digestion. In fact, it's deeply intertwined with this nervous system, which is why our gut and our brain are linked in both directions. And you also talked a lot, I think, about how, you know, we now understand the microbiome is really important.

58:51And that even when you were studying 15 years ago, it was sort of much less of a focus. There's been that big change. You talked about the fact that there's really been a rise in sort of gut-related issues, whether that's IBS or like these serious diseases like IBD, and that likely diet is playing a big part in that. But you said not only diet, it might also be an environment. And you talk quite a lot about antibiotics and you shared this study that I'd not heard of before. You said there was a nurse's study in the UK, like a big one, I think you said like 14 ,000 nurses, where the nurses who had had sort of very heavy antibiotic use actually had sort of lower scores on memory tests than the rest.

59:32Did I get that right? And so this idea that somehow this regular use of these antibiotics over and over again might be having these unexpected negative impact with the microbiome somewhere else. But you also said really clearly it can be life-saving. So you absolutely shouldn't feel you should never have antibiotics. And again, you gave me yet another brilliant vision, which is don't create a nuclear winter in our guts. So if you are taking the antibiotics, you want to try and make sure that they are focused for the problem, not just kill all the bugs because we understand now they're good. Then I think we talked about what can you do to improve?

1:00:07And you said like food is the number one thing about better gut health. Fiber is your first thing you wanted to talk about. You said it's a prebiotic. It's like the fertilizer for our bacteria. Ideally, you'd be getting at least 30 grams a day, which we know is not what most people are. But then you also talked about variety, diversity of colors, all these sorts of things. Interestingly, you're a doctor, but you were not very keen on probiotics, at least for what people can buy themselves. You said there's no real guarantee this is going to work. Our microbiome is unique. You haven't really seen the data that supports it.

1:00:46And indeed given a choice, better to take fermented food, because even if the bugs didn't work, the rest of this is going to be valuable. I asked you about the foods that will magically improve my mood. And what you said is like, you totally see the impact of food overall being able to improve your mood, but you're very skeptical about like an individual food being like the magic thing that will improve us. So maybe like if you change your whole diet and your microbiome, but you don't buy that. And then finally, I think we wrapped up with this idea that you should sort of respect your natural gut demands.

1:01:21So, you know, like you said, like your gut also has a circadian rhythm. So if you're used to like having a bowel movement, you know, seven in the morning, your body's expecting that and you really want to make that happen. And indeed, if your body is saying like, it's time to have a poo, then you should go for it rather than hold it in. And actually have the same view about, you know, know, the fart, this is stuff. And I would note if you're on audio that I managed to make Karan smile a bit just by saying the word fart. So even you find the word slightly embarrassing, but your point being that these are sort of natural bodily functions and resisting it all is part of what also potentially sort of backs everything up further up in the system.

1:02:02Yeah, we need to make number two is number one. I think that is a brilliant place to finish. Karan, thank you so much for joining us. I really enjoyed it. I think I totally understand why you have this amazing ability to communicate these ideas in a powerful and memorable way. Thank you for having me and giving a platform for bowel-related stuff. It's a pleasure. I hope we can convince you to come back again in the future. Absolutely. I really enjoyed having Dr. Karan on the podcast today. My biggest takeaway is that if we look after our gut by feeding our microbiome with the right foods, it will look after us in return.

1:02:37Now, if you'd like to start taking better care of your microbiome, then listening to the show is the perfect place to start. But you can only do so much with general advice from a weekly podcast. If you want to feel much better now and hopefully live many more healthy years, you need something more. And that's why more than 100 ,000 members trust Zoe each day to help them make smarter food choices. Combining our world-leading science with your Zoe test results, Zoe is your daily companion to better health for life. So how does it work? Zoe membership starts with at-home testing to understand your unique body.

1:03:13Then Zoe's app is your health coach, using weekly check-ins and daily guidance to help you shift your food choices to steadily improve your health. I rely on Zoe's advice every day, and truly, it has transformed how I feel. Will you give Zoe a try? The first step is easy. Take our free quiz to find out what Zoe membership could do for you. Simply go to zoe.com slash podcast, where as a podcast listener, you'll get 10 % off. As always, I'm your host, Jonathan Wolfe. Zoe Science and Nutrition is produced by Julie Pinero, Sam Durham, and Rich Willen. The Zoe Science and Nutrition podcast is not medical advice.

1:03:52And if you have any medical concerns, please consult your doctor. See you next time.

1:04:16As you can imagine, hosting this podcast, running Zoe, juggling family life, it all keeps me pretty busy. So I try as best I can to stay energized and show up well in all those parts of my life. by fueling my body with the right food, by exercising, and by adding a scoop of Daily 30 to my meals every day. If you haven't heard of Daily 30 yet, it's the gut supplement designed by our gut health scientists here at Zoe. It's made of over 30 high-quality, hand-picked plants, including seaweed, fungi, and different types of fiber. Better yet, it contains ingredients that support gut health, digestion, and energy, which is ideal for packed calendars and busy lives.

1:04:59Simply add one scoop a day to any meal for an extra boost of fiber and plant diversity. And because it tastes delicious on just about anything and adds a satisfying crunch, it quite quickly slots into your life, becoming a daily healthy habit you'll always have time for. By the way, whenever we talk about Daily 30 as a good source of fiber, we're required to say that it contains four grams of total fat per serving. Obviously, that's all amazing healthy fats from plants. So order yours today at zoe.com slash daily30. Thanks for listening and see you next time.