The Food Medic - S6 E8: Deep dive into the gut microbiome

Episode Date: August 25, 2021

Dr. Ruairi Robertson has a B.Sc in Human Nutrition from University College Dublin and a Ph.D in Microbiology from University College Cork. He has worked in a number of Universities and research institutes around the world including Harvard University, Massachusetts General Hospital and University of British Columbia. His research examines the many ways the gut microbiome affects human health, from belly to brain. He is currently based in the Blizard Institute, Queen Mary University of London, where he is researching the role of gut microbes on the health of mothers and babies.This episode covers:- Recap of the gut microbiome - The hygiene hypothesis, our microbiome and immunity- What shapes our microbiome? - Personalised nutrition and microbiome testing - The influence of exercise on the gut.- The microbiome and circadian rhythms- The Gut-brain axis- The oral microbiomeIf you loved this episode make sure to give it a review, rating (hopefully 5 stars) and share it with your friends and family. instagram/twitter/facebook: @thefoodmedicwww.thefoodmedic.co.ukThis podcast episode is sponsored by WHOOP. Right now, you can get your first month free when you checkout through join.whoop.com/thefoodmedic Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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University College Cork. His research examines the many ways the gut microbiome affects human health from belly to brain and he's currently based in the Blizzard Institute Queen Mary University of London where he is researching the role of the gut microbiome on health of mothers and babies. So I know we've spoken about gut health many, many times on this podcast, but this episode is certainly very different. We touch on new areas of research that I haven't covered on the podcast before. So I really do hope you enjoy and I can't wait to hear your feedback. Today's podcast is brought to you by our sponsor Whoop. Whoop is one of the most popular fitness wearables right now. It's a 24-7 digital fitness and health coach that provides actionable insights to help you recover faster,

train smarter and sleep better. Whoop is unlike most other wearables in the sense that it doesn't just tell you what you've done, but it tells you what you really need to know. So I've been using my WHOOP for a few months now and I am so impressed with the amount and level of insight it can provide you. So each morning when you wake up, you get a recovery score from WHOOP based on your sleep and other recovery metrics

such as heart rate variability and resting heart rate. That score helps to guide your day, whether you should push yourself and go all out, pull it back a little, or actually just take a rest day. The greatest feature for me is the built-in sleep coach, which lets you know how much sleep you should be getting based on your expected activity for the following day. It also tracks all four stages of sleep, so you can get a breakdown of how much REM and slow-wave sleep you got. It's allowed me to figure out ways which work for me to optimize my sleep. Whoop can help anyone perform better.

Whether you're preparing for a 5K, training for an event, or just looking to build healthier habits, Whoop can help you make smarter lifestyle decisions with data that is personalized to you. Right now you can get your first month free when you check out through join.whoop.com slash thefoodmedic. So I think to start it would be great to just get a bit more of your background and the current research that you're doing. Yeah absolutely. So I didn't have a clue what I wanted to study when I was leaving school. And the best advice I got was to just do or study what you're interested in and what you love.

And so the first thing that came to mind for me was food. I come from a family of, my mum at least anyway, is a very good cook. So I figured out how I could study food. And this course, human nutrition was starting up in University College Dublin. So, yeah, I went and did that for four years and became fascinated by how food affects your body in different ways, how it can maybe contribute to disease and how it may even help prevent certain diseases. And I became very interested in the biology behind that. And I got some experience working in labs and kind of being at the forefront of discovery and nutrition. So I went on to do a PhD then in Cork, and during which time I spent a year or so over in Boston as well. And I was lucky in a sense that this was the time that the gut microbiome field was really

kicking off. And so I kind of managed to jump on the bandwagon a bit, and I'm still kind of riding that wave of the excitement of gut microbiome research, which I'm sure we'll talk about. And so I had this great kind of experience and expertise then combining human nutrition with microbiology. So I had an undergraduate degree in nutrition, a PhD in microbiology. So I had an undergraduate degree in nutrition, a PhD in microbiology. And so I've continued to research that and the various ways in how the microbes living inside of us and on us contribute to our nutritional state, contribute to health and disease and how they interact with our diets. So I've studied that in various different angles,

both in kind of the more common Western diseases that we think about, obesity, diabetes, but also in the very interesting areas looking at how the gut might be connected to the brain. But I've since kind of gone on and started looking at more forgotten disorders and diseases and looking more at child under nutrition, which is still a major problem around the world, and how the bacteria and other microbes that we're exposed to in early life may regulate our growth and maybe prevent us growing very well. And interestingly, there's a lot of crossover between the disturbances that we see in our gut and in our nutritional state in the

Western world when we think about obesity and weight gain. And there's a lot to be learned that we can apply to the other side of the spectrum in terms of underweight and children who aren't growing as well as they should. Yeah, absolutely. I think we've probably underestimated how much of a role our gut has in terms of our overall health, and how kind of all of the systems in our bodies are so intricately linked up. But before we go any further, let's just kind of have a recap of what the gut microbiome actually is when we're talking about it. Absolutely, yeah. So the gut microbiome is the term given to all of the microorganisms living inside your gut. And even sometimes people get a bit confused what we're talking about when we

talk about our gut. And that in a kind of vague sense is the tube that connects your stomach and goes all the way out of your body. And it forms up part of a larger system called the gastrointestinal system, which would, you know, start at your mouth and end up down at the other end of your body. And it forms up part of a larger system called the gastrointestinal system, which would, you know, start at your mouth and end up down at the other end of your body. So we have trillions and trillions of microbes living inside our gut and inside our whole intestinal tract. And, you know, for years, we thought that most bacteria and viruses were harmful, and we needed to get rid of them. But actually the fascinating science that has happened over the last few years is showing the really, really important role that all these

trillions of microbes have in our body, especially for gut health, but also for the health of all other kind of systems in our body as well. Yeah, absolutely. Let's start from the beginning then. How do babies acquire their microbiome? Yeah, good question. There's a lot of debate in this scientific field about whether babies, when they're in the womb, are exposed to bacteria or not. For years and years and years, it was assumed that babies were sterile inside the womb. But a couple of pieces of evidence show that they may be exposed to some bacteria and some viruses maybe when they're inside their mother, although it's probably not a lot. So they're essentially probably sterile before they're born. So as soon as a baby comes out, either by C-section or by natural delivery they're suddenly coated with trillions of bacteria

viruses fungi all these other microbes which begin to develop and grow both on them and in them to kind of create this microbial organ and most of which are in their gut so most of these bacteria come from their mother especially if they're born through a standard vaginal delivery. So it comes from the mother's gut, comes from the mother's birth canal. And then as they are fed breast milk, some of the bacteria come from the breast milk. Some of it just come from the surrounding environment. And the fascinating research shows that, however, babies who are born by C-section tend to acquire different types of microbes because they don't get that initial coating of bacteria from the mother's gut and

the mother's birth canal. They instead acquire a few microbes that tend to come from the mother's skin, from the kind of surrounding hospital surgery room or the environment. And so they get a different microbial coat, I suppose, in those first few days of life. So really, it's from our mothers that we get our initial gut microbiome. And as babies kind of develop and grow in the first few months of life, they begin to acquire more and more microbes from their surrounding environment. So if you think of a baby, then, as they begin to crawl and start moving around on the floor or start being picked up by other people or eating different foods, they'll start to develop

this microbial organ as they gain different types of microbes from all these other sources that aren't just from their mother. Absolutely. And so do we see differences in health outcomes between babies who are born vaginally or via C-section? Yeah, we do. Interestingly babies that are born by c-section tend to have higher rates of allergies, asthma and these kind of chronic immune disorders throughout childhood and maybe even into later life. A lot of this is what's

known as observational evidence so it's quite hard to test, is that truly a difference, or is it just a nature of the kind of environment that a baby is coming from, if they're more likely to be born by C-section. However, it does sound plausible because of this initial coating of bacteria is different. Their immune system gets exposed to different bacteria in early life through this kind of technically unnatural process of being born by C-section. And therefore their immune system isn't trained against and to recognize these important microbes that they should be exposed to if they were born through a normal delivery. And so that's why their immune system might become a bit more reactive in later childhood. And they might tend to, you know, develop asthma, develop

allergies, and things like dermatitis, and possibly even gain more weight into later life and be more prone to other chronic disorders as well. So interesting. And I guess this kind of theory and the fact that exposing babies to bacteria early on is really important for their immune system priming ties in with the hygiene hypothesis. Can you chat a little bit about that and how exposure to bacteria is beneficial for immunity? Yeah, absolutely. So this was a guy back in the kind of 1960s, 70s, 80s, around that time called David Strachan. And he initially proposed what he called this hygiene hypothesis, where children who were becoming less exposed to microbes or infections in early life were more at risk of developing

asthma and hay fever and some of these kind of inflammatory disorders that I've mentioned. And this seems to be playing out to today as well. We see this really interesting evidence that children who grow up in farms or children who grow up with pets or children who grow up in with more siblings or go to daycare, they tend to be less prone to developing things like asthma and allergies and some of these inflammatory conditions because they are exposed to a higher diversity of microbes in early life. And their immune system is constantly being trained in these really early developmental periods. And on the other hand, if you have children who maybe get lots of antibiotics in early life, who've been born by C-section, who kind of live

in a hyper clean, sterile environment, their immune system doesn't get trained and therefore it becomes more reactive. And so that's what's known as the hygiene hypothesis that actually being too clean or maybe not clean is the wrong word, but not being exposed to enough microbes might actually have detrimental effects in the long term. Yeah, it's really interesting. I wonder whether this era that we're going through where hand sanitizing is at another level will change. Absolutely. Yeah, I think that could be the most fascinating study to see, you know, children that have been brought up over the past year and a half where they're been kept at home, don't have these interactions with the outside world as much as other children might

have is that related to you know their their disease risk later on i think i think that could be really interesting yeah absolutely so we spoke about some things that can shape our microbiome but what other things can shape our microbiome i I mean, I think a lot of people are aware that diet plays a big role and at the moment probiotics and prebiotics are very trendy and everyone's chatting about them. Yeah, there's lots of things that can affect our gut microbiome and really anything in our lifestyle that we think of that can affect our disease states can affect the microbes living inside of us as well. As you mentioned, diet probably has the strongest effect on our gut microbes because if you think about it, these are microorganisms that are lining your whole intestinal tract.

So they are directly exposed to all the nutrients that you consume every day. But other things such as even like exercise, sleep, alcohol and smoking, of course, can all impact the types of microbes living inside of us. And there's even fascinating evidence that even stress can have an interesting effect on our gut microbiome, maybe. And we see this if we think of certain disorders like IBS or other kind of gut disorders, they're highly and closely linked with anxiety and certain mental health states. So there might be kind of links between our kind of stress environment and our gut as well. So probiotics also obviously can in some way affect our gut microbiome because you're adding

in new bacteria into this microbial ecosystem in your gut. But really the evidence shows that they don't, aside from adding in the bacteria that is in probiotics, they don't have a major effect on all the other bacteria that are there. They can have their own beneficial effect as long as you're taking them, but they don't cause major changes to the composition of your microbiome. And in fact, all these other lifestyle factors such as diet and exercise and sleep and stress probably have more profound implications on the composition of your gut microbiome. Yeah, absolutely. I think that, you know, obviously we just mentioned probiotics and

there's like a lot of functional foods now and things like that that are containing or claim to contain probiotics but i don't know what your thoughts are for people who don't have any gut issues and are taking them kind of with the presumption that it will improve health do you think there's any benefit in just taking it for for the sake of it? I suppose the evidence is conflicting. Not really. If you're young and you're healthy anyway, a probiotic isn't going to do that much for you. Having said that, a huge number of people experience some sort of gut issues in their lifetime. If you take the conditions which are known as the Rome criteria for IBS or some of these functional gastrointestinal disorders, as they're known,

which include things like bloating, abdominal pain, gas, and discomfort, something like 40% of people experience them over certain periods of time in their life. So we all go through gut discomfort at some point, probably. And therefore, even though we're healthy, a probiotic can, or certain probiotics can help in alleviating some of those symptoms. So for a day-to-day kind of elixir of life, no, I wouldn't say probiotics are this kind of amazing golden pill. But if you do experience some of these symptoms of poor gut health or even certain other conditions, there are very specific probiotics that can help. The issue is that historically, companies would take any old bacteria and throw it into a yogurt or some other drink and call it a probiotic.

But that isn't the case because the specific definition of a probiotic states that it has to have a specific health benefit that has been, I suppose, proven in humans and through rigorous scientific studies. So there's only really a kind of handful of rigorously well studied probiotics on the market that have certain scientific evidence for alleviating certain disease states. There are certain times when taking a probiotic can be helpful. For example, if you've taken antibiotics, there is some good evidence that it can reduce antibiotic-associated diarrhea. If you're traveling to some far-flung place in the world,

which none of us have been able to do over the last year and a half, they can also reduce traveler's diarrhea. So there are certain cases when probiotics can be beneficial. In general, if you're young and healthy, you're not experiencing any symptoms, it's not going to do much for you. Yeah. Okay. That's good to clear up. And so I'm interested in your thoughts on microbiome testing, which have also soared in recent times and people being able to post their poo. Yeah, I know. Glamorous, isn't it? It's so glamorous. Yes, this is a kind of another contentious issue in this field. It is interesting and it's become more common for people to study it. However, right now, if you were to ask me today,

will you be able to tell much from doing this? Not really. If you're interested in what your microbiome looks like and what type of bugs are living inside you, by all means, send off a stool sample and you can get back some very interesting research if you're kind of interested in what's happening in your own body.

However, it's not going to tell you anything major in order for you to, you know, do some amazing things to your body, make any amazing changes to your lifestyle. If you were to give me your report of your gut microbiome, all I'd really be able to tell you right now is to say, maybe increase the diversity of your diet, eat more fiber, and give you kind of generic advice. Having said that, there are a couple of companies, which I won't name right now, because I don't like kind of naming companies, which are working on using these results to create personalized treatments for people. And they have published some of this evidence, which is really exciting, where they show that they can take people's gut microbiome along with other biological readouts. So their kind of height, their weight, their lifestyle.

And they can put this into a kind of algorithm, a really complex machine learning algorithm and predict how people will respond to different foods, predict how their blood sugar will respond. And so by doing this, and then creating personalized diets for people, they can really, really accurately predict who will, or what type of diet will be the best for each person. So much so that they've kind of been working on personalized diets for each people based on an individual's microbiome, that may even be more effective than general national dietary approaches for, you know, improving your blood sugar, which is really important when we think of people who are pre-diabetic or people who are maybe gaining weight in an unhealthy way, such that they're at risk of certain diseases. And so that really is the future of personalized medicine. And we may be able to send off our stool samples in the future to get personal readouts. But right now, if you want to send off your stool sample and get your microbiome tested, it's purely more for your own interest, I'd say.

Yeah, I think personalized nutrition will be really interesting. But I imagine that's not in the near future based on how accessible that would be for many people. Yeah, I mean, accessibility is always going to be an issue for any sort of new nutrition or medicine. It depends how you look at it, but this isn't going to be something that's going to be on the NHS immediately. It's going to be a commercial application for people to create their own personalized diets but it you're right to say that it won't be available immediately for probably the people that most need it and that is an issue with all these kind of personalized medicine and personalized nutrition yeah of course so you touched on exercise and its influence on the microbiome. Can you tell us a bit more about the research around that? Absolutely. Yeah. Again, this is kind of relatively early stages and that's

a kind of caveat that I'd have in a lot of this microbiome research. There's a lot of hype, but we have to be careful that we're only talking about what evidence we actually do have. So there are a few studies showing that if you get people who are not that mobile, mobile is the wrong word, sorry, they don't exercise that much. And you put them onto a kind of exercise regime, the composition of their gut microbiome does tend to change in a kind of more beneficial way. And that kind of makes sense, I suppose, because getting up and moving actually gets your gut working, it actually helps a bit of digestion. And that kind of makes sense, I suppose, because getting up and moving actually gets your gut working. It actually helps a bit of digestion. And, you know, if you've ever had a big meal and

you need to kind of get things moving and they're kind of going for a walk around, you can do that. And so getting your gut working like that actually changes the composition of your microbiome. There is some kind of interesting evidence in kind of lab-based or animal-based studies that it works the other way around. The composition of your microbiome may affect your fitness. And so there was a really interesting study in people who ran the Boston Marathon a couple of years ago, and they took stool samples from these people and put them into mice and did all these interesting studies in the lab in mice. That's the big caveat. This was in mice. And they found that certain bugs within these people's gut microbiome

could break down lactate, this molecule that builds up into lactic acid. And we all know that lactic acid is important in athletes because it gives you cramp and affects your fitness, I suppose. And so they were showing that your gut microbiome may actually affect the lactic acid buildup in your body. And therefore, it's possible that you could take a certain probiotic or change your microbiome in the future to therefore improve your fitness. So there's all this kind of interesting lab work, but I wouldn't say it's at a stage yet where I can say, take this certain product for your microbiome and you'll become fitter. The kind of general dietary and lifestyle advice still goes whereby get out do your 30 minutes of exercise every day

and that amongst diet and other things will actually have benefits to your gut microbiome as well as other health benefits for your body yeah absolutely and i guess the benefits are also increased if we're doing that outside in nature when we're surrounded by lots of other bugs. Yeah, absolutely. That kind of comes back to the kids growing up on a farm kind of study. You know, if we expose ourselves to other types of microbes, that kind of increases the diversity of your microbiome. So, you know, if you have the choice of going on a treadmill in a gym or going for a run through your local forest or park, by all means go outside, you know, and that exposure to

microbes in the environment can kind of have huge benefits. Yeah. There's so many benefits to kind of just getting outside as well from a kind of mental health stress reduction point of view as well. Absolutely. And I guess sleep is another area of our lifestyle that could impact our gut health. So how does sleep influence the gut and our microbiome? Do microbes have circadian rhythms or are they aligned with our circadian rhythm? What's the relationship there? Again, it's kind of complex that we're trying to kind of delineate how much microbes have their own control over these kind of rhythms or whether they are dependent on humans' circadian rhythms. So our circadian rhythm is our body clock.

It's just a fancy word for our body clock, really, in that our body goes through these daily processes at certain times of the day. And that's kind of dependent on our sleep cycles, dependent on when we eat food, when we rest, etc. So our gut microbiomes seem to have a circadian rhythm as well. They perform certain functions at certain times of the day. Now that is probably most likely dependent on the times that you eat food, the times that you go to the bathroom, the times that you rest, for example. However, they may have their own kind of independent control over this as well. And so they can even interact with melatonin, this really important hormone that we produce in our bodies that regulates our sleep cycle, to control various processes. So it might possibly

mean that our microbes at certain times a day are better at digesting foods, for example, or they're better at resting at certain times a day. And so this might be the reason that eating at certain times a day may have worse health outcomes or better health outcomes. Again, like I give a caveat for everything, this is kind of still at early stages of research. So the best advice you can give to people is to keep your kind of meal timings the same time every day and don't eat too close to bed. But it's possible that we'll kind of learn in the future that your microbes might respond to certain foods at certain times of the day better than other foods or other times of the day. And they do this by kind of interacting with melatonin and other parts of the human body clock.

Yeah, it's fascinating though. Yeah. Yeah, it really is. And I guess that brings us on nicely to the gut-brain axis and the influence that our gut has over our brain health and also our mood. I feel like this is something that's widely spoken about online. And, you know, people often quote that majority of our serotonin, which is a happy hormone is produced in our gut. And, you know, that's why if we look after our gut, we can look after our brain, but there's lots of other kind of

mechanisms going on there. And I'd love to speak to you more about this. Yeah, absolutely. So that is the one fact that seems to be thrown around a lot. You're right that 95% of your serotonin is produced in your gut. And it is true, but it's not the whole truth because most of that serotonin doesn't pass into the brain. So the serotonin that's produced in your gut probably doesn't have the same effect that the serotonin doesn't pass into the brain. So the serotonin that's produced in your gut probably doesn't have the same effect that the serotonin in your brain does. Having said that, serotonin in your gut plays a lot of roles.

It actually helps with gut function and helps with kind of motility and the normal functioning of your gut. So serotonin, although we know it as being a happy hormone, actually has all these other roles in the body as well. But this production of things like serotonin and other neurotransmitters in the gut isn't the only way that our gut is connected with the brain. It's connected through a vast network of nerves known as the peripheral nervous system. And we have hundreds of millions

of these nerves that connect our gut physically to our brain. And one of the kind of most well-known nerves is known as the vagus nerve, which connects the gut to the brain and sends signals in both directions. And this may be why, as I mentioned previously, people with IBS really commonly also experience anxiety, depressive symptoms, and other kind of mental health disorders. We don't know yet the chicken and the egg of this situation. You know, there's a bit of both probably to it. People that are stressed are probably more likely to have gut symptoms for a variety of reasons. And people that have poor gut health may be more likely to be anxious and stressed for a variety of different

reasons. So that's just kind of two ways that our gut is connected to our brain through the kind of electrical messages that are sent through the peripheral nervous system, through the hormones and neurotransmitters that are produced in the gut. But there are plenty of other ways as well. For example, the gut is the center of our immune system. We have roughly 70% of our immune cells are located in our gut. And our immune system plays a huge role in our brain health as it does for the health of much of other parts of our body, whereby if we have chronic inflammation or our immune system is kind of hyperactive, that can trigger poor brain health as well. And so I suppose our gut is really the center of that as well. If we have

an unhealthy gut that is constantly triggering our immune system to produce inflammatory chemicals, that is another plausible way that our gut might impact our brain health. So this is kind of another kind of new area of research and all these pathways are slowly being delineated. And slowly, we're finding different ways that targeting the gut microbiome may improve brain health, or even targeting the brain may improve gut health. So I can give a couple of examples of that. And, for example, people who go under kind of mindfulness treatments, or people who go under cognitive behavioral therapy, and this is in really good randomized controlled trials, this can actually significantly improve symptoms of IBS, for example. So if you

take a big group of people, put half of them on mindfulness or cognitive behavioral therapy, half of them on a kind of placebo equivalent, I suppose, those that get these kind of brain targeted therapies can actually physically improve their gut symptoms. Other things work in the other way around as well. Very specific prebiotic or very small number of probiotic treatments or other dietary interventions have actually been shown to reduce stress hormone, to reduce anxiety and certain depressive symptoms in some small studies. So there is this true connection between the gut and the brain, which is slowly being uncovered. And it's, I suppose,

gives us a holistic view of how we can appreciate that our body is connected in a huge number of ways, particularly our gut and our brain. Yeah. And I guess, thinking about food and mood, based on the evidence we have, I know that we can't really prescribe a specific diet, but it seems to be more along the lines of a modified Mediterranean style diet. Is that correct? Absolutely. I mean, plants are the food for our gut microbes. They thrive on fiber and polyphenols and prebiotics fibers from a variety of different plants. They thrive on plant diversity. That's not to say that they don't digest meat and they can't tolerate meat. Of course you can, but they really do thrive on plants and the kind of healthy fats as well that you get from a Mediterranean diet.

So kind of two take-home points that I have if people ask on a diet that's good for your gut microbiome, one would be every time you go shopping, buy a different food or a different plant-based food that you don't usually buy. We're all guilty of going into the shop when we're tired and we'll pick up the same, you know, broccoli and peppers and bring them home and make the same meals. However, our gut microbiomes really thrive on diversity. So try a new spice, try some new mixed nuts, try a new grain, you know, Tesco and all these other shops have a huge variety of different grains, but we all probably tend to revert to rice or maybe quinoa if we're feeling fancy. But you know, there's a huge other number of grains such as pearl barley and bulgur wheat and all these other things which provide a variety of

different fibers and for our gut microbiome, which can really help them thrive. And then the second tip is what people may have heard is aim for 30 different types of plants each week. It's a fairly arbitrary number, but it's a good thing to aim for. So add up all the fruits, vegetables, nuts, seeds, grains, any of these plant-based foods that you eat every day and try to aim for 30 different ones in a week. And that will really build up the diversity of foods that you're feeding for your gut microbiome that they really thrive on and it helps them to remain healthy and keep your body in check. Yeah, absolutely. I love that message. And you gave a really good description of when we talk about the gut, it's not just the gut or our intestines as many of us visualize it as. It is everything from mouth all the way to our anus,

essentially. And so we have bacteria in all parts of our body outside of our gut as well. But let's talk about the mouth and the links between oral health and health and disease. Yeah, this is another kind of fascinating area of research that people are looking at the microbiome outside of the large intestine. It's not just the gut microbiome, but looking at microbes in the mouth, in the lungs, in the birth canal and everywhere else in the body. And so our microbes in our mouth actually might play a role in digestion of certain foods even. So there's certain bacteria in the mouth that can actually break down some nutrients in things like beetroot, these kind of nitrates. They can even play a role in digestion before you've even swallowed, which is really interesting. But in terms of a kind of disease state, there's some really

interesting evidence to show that certain bacteria from the mouth may even travel down through the bloodstream and work their way into the gut through that kind of route. And this has been associated with things like colorectal cancer and things with heart disease. So again, this is preliminary evidence, but it suggests that maybe poor oral health or the kind of colonization of a certain disease-causing bacteria in the mouth can actually have implications for other parts of your body. And the scientists have studied this by looking at very specifically the genetics of the type of bacteria they pick up in a tumor in the gut, for example, or in an atherosclerotic plaque in the blood, and match that up to the bacteria they

find in that person's mouth and see that they're very, very similar. So, you know, microbiomes aren't just considered in the gut. They kind of play a role in our health and disease all over our body. I don't want to say too much about the mouth because I'm not a dentist and I'm sure plenty of dentists can say a little bit more than me. But from what I know, even the American Dental Association have taken off the recommendation of daily flossing and mouthwashes. Sorry, maybe not flossing, but mouthwashes anyway, because that might even disrupt the kind of normal microbiome of the mouth. I stand to be correct on that. But I remember reading some data on that before that we consider it like antibiotics

or other things we're putting into our gut, are we putting into our mouth every day that will kind of disrupt the the kind of normal microbiome of the mouth of course you need to brush your teeth every day because you don't want to build up a bad bacteria but it's it's all about a bit of balance yeah absolutely it's so fascinating i look forward to seeing more research coming out in that field and it's definitely nice to see it spoken about a bit more so kind of as your as your takeaway messages Rory what would you say are your kind of big rocks when it comes to gut health when someone's thinking about what they can do in their lifestyle to maximize the health of their gut yeah I think I've gone gone through a couple already in terms of you know diversity of the

diet is probably the easiest and most important thing you can do for your gut so aim for that 30 a week and aim for a different food every time you go shopping the other little tips i give to people to make that easier is buy a huge load of mixed nuts seeds chop them all up and put them in a jar and that is a great way to add five or six different plant-based foods to a meal. You can sprinkle them on cereal, you can sprinkle them on salads, on different foods. And it's a great way to feed your gut microbiome with different types of foods. That's kind of diet. You have the other kind of lifestyle tips that are important, not just for your gut microbiome,

but for other aspects of health, you know, sleep and exercise. One important thing for the microbiome is antibiotics as well. I think we've got better at this over time, but antibiotics, when they're not necessary, are really, really bad for our gut microbiome and for our body, because they can lead to antimicrobial resistance, which is probably going to be the next big global health problem after COVID. And, you know, a lot of people I know would go on holiday and just say, I'm just taking antibiotic with me just in case, or, you know, they might have a cold and just go in and get an antibiotic just in case. Antibiotics do not work for colds because colds are caused by viruses. And taking an antibiotic when it's not necessary is actually really bad because it kills all of

the good bacteria inside of your gut as well, which makes it easier for disease-causing bacteria to then colonize your body. Kind of ironically, taking an antibiotic when it's not necessary can actually make you more prone to an infection later on. Of course, antibiotics are really, really important when you do have certain specific infections, and they are life-saving, but we just have to make sure that you only take antibiotics when it is necessary. And so if you do have to take an antibiotic, which of course sometimes people do have to, there is evidence that taking certain probiotics either during that course or after it can prevent antibiotic associated diarrhea.

So that's kind of like the lifestyle tips, diet, sleep, exercise, and avoiding antibiotics when necessary. And we kind of briefly spoke about kind of babies and mothers as well. Exclusive breastfeeding is the best way that you can develop your baby's gut microbiome as well. Even babies that are born by C-section who have this kind of disturbed microbiome that I spoke about, those that are then exclusively breastfed for the first few months of life, ideally the first six months of life, their microbiome tends to normalize then and go back to one that looks like the baby was born by a kind of normal delivery.

So that's another way, if you're a mother or an expectant mother, that you can ensure that your baby kind of gets the best microbial start in life as well. Yeah, just looping back to the antibiotic message, I completely agree with you there. And I think that that's something that there's definitely been a lot more public health attention drawn to. But things like non-steroidal anti-inflammatory medications can also disrupt the gut microbiome, right? Oh, absolutely. Yeah, there's really interesting evidence now showing how different prescription medications can disturb the gut microbiome in a way. But this kind of works in a two-way street. So for example, yeah,

the non-steroidal anti-inflammatories definitely have a huge effect, but PPIs, these proton pump inhibitors that people get given for gastric reflux, yeah, these kinds of issues, they have a huge effect on the gut microbiome as well. So I'm not a medic here, so I'm by no means going to tell people to not take medication. Medications are very important, but there are certain prescription medications which can have long-term effects on the gut microbiome. The other side of that is that certain prescription medications actually depend on a healthy gut microbiome to actually work. There's really interesting kind of evidence to show that a lot of prescription medications only work in 50, 60% of people. And this may be because that

these people have different microbiomes, which aren't amenable to the kind of metabolism of these drugs in their body. And so the kind of future treatments may involve a certain medication plus something that targets your gut microbiome as well to make sure that that medicine works for you. And that kind of comes back to these kind of personalized medicine things. So yeah, medications have an effect on the gut microbiome. And you know, we have to take them if we're advised by our doctor, but to consider the pros and cons of all these things as well, when considering our gut microbiome. Yeah, absolutely. I think the message isn't to stop medications that you're prescribed, you're given.

Absolutely not, absolutely not. No, but I think when it comes to over-the-counter medications, where now you can get omeprazole or PPIs over-the-counter, and I know a lot of people will just kind of pop them here and there and not chat to the doctor about it. So it's just something to bear in mind if you do find yourself relying on these medications without consulting with someone who's qualified to just make sure it's just something to bear in mind if you do find yourself relying on these

medications without consulting with someone who's qualified to just make sure it's the right thing you should be doing anyway but absolutely i don't think that's something that we considered in the past you know but it's so interesting regarding the synergistic effect of probiotics and medications like you just mentioned i imagine that will be something of the future absolutely i think so yeah we'll all hopefully have personalized medicine in the future but it could be a while off yet yeah okay amazing well thank you for the conversation today it was absolutely fascinating no thanks for having me on I was it was great we we touched on a bit of everything I think yeah babies medication

under nutrition I'm not too sure what we may stay on i know i wanted to get my money's worth so if people want to hear more from you and the kind of topics that you're chatting about today where can they go yeah i'm on all kind of social media i think i have different names on all my different social medias i think i need to uh to work on that i'm um rory robertson on twitter if you can spell my name correctly the the Nutri Doctor on Instagram. Yeah, if you Google my name, you'll find all of the all of the different social media links. Amazing. Do you have a podcast as well? I do. Yes, I did a couple of series over lockdown. It's kind of my lockdown project.

And it was a kind of a scientific podcast where I was interviewing kind of, yeah, microbiome experts, so people working in the field. So yeah, by all means, people can go back and listen to that as well. And if there's interest, I could do another series. So I'll see to the listenership numbers spike up again. Yeah, I'm sure they will after this. Amazing. Well, thank you for the chat. And I hope you have a lovely rest of the day. wow what an interesting conversation that was Dr Rory Robertson um one of my favorite topics is gut health and so I always love sitting down with someone who's researching this area and just really dig deep so I hope you enjoyed it as much as I did and if you did you know the drill please do leave a review a rating and if you want to share it with friends or family I would love to have more people join

the community that's all from me and I'll see you again next time