Most replayed moment: The hidden battle inside your gut | Tim Spector & Nicola Segata

Today we’re talking about gut microbes. Professor Tim Spector often refers to the microbes in our gut as ‘mini pharmacies’. This is because they provide us with powerful chemicals that help support our health. But not all gut microbes are on our side. In fact, there’s an ongoing battle in our digestive system between the beneficial bugs and those that wish to do us harm. I’m joined by Tim Spector and microbiome researcher Nicola Segata join me to explore this microscopic war, and explain how simple changes to your diet could help tip the balance toward the good guys. 🌱 Try our science-backed and tasty wholefood supplement Daily30 Get our brand-new app and Gut Health Test designed by world-leading gut health and nutrition scientists to build healthy eating habits 👉 Join ZOE Follow ZOE on Instagram.📚Books by our ZOE Scientists The Food For Life Cookbook Every Body Should Know This by Dr Federica Amati Food For Life by Prof. Tim Spector Ferment by Prof. Tim Spector Good Mood Food (preorder) by Prof. Tim Spector Free resources from ZOE The Hormone Harmony Guide: Tuning Your Body’s Internal Orchestra Eating for Better Brain Health: Your brain-gut blueprint How to eat in 2026 - Discover ZOE’s 8 nutrition principles for long-term health Live Healthier: Top 10 Tips From ZOE Science & Nutrition Gut Guide - For a Healthier Microbiome in Weeks Better Breakfast Guide Have feedback or a topic you'd like us to cover? Let us know here. Episode transcripts are available here.

• 0:01Speaker 00

  Hello and welcome to Zoe Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Professor Tim Spector often refers to the microbes in our guts as mini pharmacies. This is because they provide us with powerful chemicals that help support our health. But not all gut microbes are on our side. In fact, there's an ongoing battle in our digestive system between the beneficial bugs and those that wish to do us harm. I'm joined by Tim Spector and microbiome researcher Nicola Segata to explore this microscopic war and explain how simple changes to your diet could help tip the balance towards the good guys.

• 0:46Speaker 01

  Gut bacteria are trillions of single microorganisms present in our gut, thousands of species, more or less, in each of us, and they are part of an ecosystem that are an interface between the food we eat, our environment and our health. So the diet, the food we eat is broken down by gut bacteria, that they are in turns producing molecules, small molecules, that are then arriving in our blood and in our system. And so they are having an impact on us.

• 1:14Speaker 02

  I call them mini pharmacies.

• 1:16Speaker 01

  Yeah, they are mini pharmacies, yes. In addition, they also interact with our cells, with our immune system. So they are directly touching and interacting with us. And so if you have the good bacteria that are able to produce good little molecules, because metabolites is good, otherwise not. So it's like an amplifier of our diet. The good bugs are amplifying the good effect, the positive effect of an healthy diet and vice versa, they can actually be detrimental for our health in other situations. So we need to push, increase our gut ecosystem to be an ally for us.

• 1:53Speaker 02

  So you want to improve, have more of these good pharmacies and you want to have less of the bad ones, you know, doing the Breaking Bad type home chemistry and producing these nasty chemicals.

• 2:05Speaker 00

  And is this real? Is there such a thing as like a good bug and a bad bug?

• 2:10Speaker 01

  It's not so much black and white. And also in our research, we see that there are bacteria that tends to be associated with better health and better diet. But we also need to consider that our gut microbes are very personalized to each of us. So it's only with big, big numbers that we can tell apart which tends to be good in which situation from those that are likely not to be there. But as Tim was saying, it's also about the diversity of them, because the more we have, the more good function they can bring to us. There is no single bacteria that can make all the work that is supposed to be done in the gut.

• 2:47Speaker 02

  So some of them, bad ones, for example, may be quite harmless in small numbers, but when the conditions are bad, they're fed the wrong foods, they have an so-called inflammatory environment, maybe the acidity changes slightly, then they can grow to an extent that they produce chemicals that influence everything around them and they become bad guys. There is this transition and so it's best to think of this as a bit of a war between the good guys and the bad guys. The more good guys you've got, the more you can squeeze out the bad guys so that it doesn't matter if they're around because they're in small numbers and they're just playing around and really any chemicals they produce are just so diluted, you don't really feel the consequences.

• 3:32Speaker 02

  But the real problems are when you lose your good bugs and suddenly the bad guys multiply and then you're really in trouble because you're producing all kinds of chemicals that attract even more unhealthy microbes and the whole thing starts to go downhill very fast.

• 3:50Speaker 00

  The three of us sitting here, will we all have roughly the same bugs inside our gut?

• 3:56Speaker 01

  Not really. I think we have around 30, 40% of species in common.

• 4:00Speaker 02

  And at the level, when you get even below the species level, the subspecies level, it's probably even less than that. It's, but you know, we're only sharing sort of 10 to 15%. So all of us have a unique set of some microbes that the others wouldn't have. And if even if you took a thousand people, you'd find nearly everyone has something unique to them. So there's a broad pattern that might be similar, but the more fine detail you get, the harder it is to find things in common, even in, as we discovered Nicola and I, when we looked to this, even in identical twins, so who have identical genes in every cell in their body, but their microbes are really only slightly more similar than unrelated people.

• 4:44Speaker 01

  And probably they are more similar because they live together, because we see that we are transmitting our gut microbes, you know, or our oral microbes. It's like pathogens. If we live together, we are going to share some of these subspecies, some of these specific strains or variants, like we know for infectious diseases now.

• 5:02Speaker 00

  So firstly, just all the bugs inside me are really different from the bugs inside everybody else. But also even when it seems like we might have the same bug, it's a bit like saying, well, we both have a dog, but you know, I might have an Alsatian and you might have a Chihuahua, they're pretty different.

• 5:16Speaker 01

  And they behave quite differently, yes.

• 5:18Speaker 02

  Absolutely, yes, that's right.

• 5:20Speaker 01

  That's the point, yes.

• 5:21Speaker 00

  Always, always worry for the Chihuahua, right?

• 5:23Speaker 02

  Even if you had two Chihuahuas, one would be aggressive and the other would be nice and docile.

• 5:28Speaker 00

  So having listened to all of this, is this just because people aren't eating a very healthy diet, Tim? So if someone is listening to this and saying, well, that's interesting, but I know I eat healthy, so therefore I will obviously have a healthy microbiome, a healthy set of bacteria inside my gut and therefore it's going to be protecting me from heart disease and these other things.

• 5:51Speaker 02

  So if someone out there is eating as healthily as they think they can for their gut, generally following, say, all my advice and Zoe's advice, on average, they will have a healthier gut score, on average, they will be living longer, et cetera. But they can't be sure they don't have the microbes that are maybe predisposing them to certain risks of disease or others they're lacking that could prevent them from having disease. And the only way to be sure about that is to do a gut microbiome test using this sophisticated genetics that Nicola has been working on.

• 6:30Speaker 00

  Nicola, is it only food that affects the makeup of my microbiome?

• 6:35Speaker 01

  It's not only food. The microbiome is a complex system that is modified by a number of things, like food for sure, but your lifestyle, the activity you do, the interaction that you have, the sleep that you have and so on and so forth. But also, as we were saying before, the interaction. We have studies, for example, of babies at the daycare that they acquire from their peers at daycare, so much microbes that they are reprogramming completely their microbiome. And this is also in adults. Two students that are starting to live together, after two, three years, they share quite a bit of their microbiome they didn't share before. So yeah, there are a lot of effects on the microbiome.

• 7:15Speaker 01

  Also, you know, pollutants, the environment we live in, so tons of effects on the microbiome.

• 7:21Speaker 00

  And Tim, if you're listening to this and you're suddenly saying, oh, I would like to have more good gut bugs, what can you do?

• 7:28Speaker 02

  Well, prebiotic, some people have heard of this term, it really means a fertilizer for your microbes and it's, it's a broader approach than a probiotic, which is just targeting one particular microbe and hoping that it has other effects. So prebiotic is scattering lots of fertilizer in the soil of your gut so that the good microbes will grow and they will push out the bad microbes. So we think that the way to improve your good microbes is definitely through fertilizers from the tools that we have at the moment. So we think this diversity of plants on a regular basis is really the key currently.

• 8:12Speaker 02

  And that's, that's available and it's actually easier to give people these prebiotics than probiotics, because there aren't any real risk, health risks associated with it.

• 8:21Speaker 01

  Absolutely. We have also to say that there are not enough percent also. Probiotics alone or prebiotics alone are not enough because probiotics are living bacteria that are getting to your gut, even next generation ones, but then you have to feed them the right food, otherwise they will not stay there. And the same with prebiotics. So it's not that you can think of taking pre and probiotics and then eat just junk food all day. So it has to be a system approach. You need to get the right environment for your microbes, then maybe you need the specific microbes to be given to you. But this does not mean that, you know, diet is not important. The first thing is diet, then some supplements can really push and improve.

• 9:04Speaker 02

  And I think in the future, we might be looking at personalized fertilizers, personalized prebiotics, really to tease apart these, these different ones. At the moment, we're going for generic, they work really well, but you know, I think we can do even better in the future.

• 9:17Speaker 00

  So what should everyone be thinking about eating more of if they want to support this sort of good bugs that we've been talking about?

• 9:25Speaker 02

  Well, the general principles are still the same and, you know, our research is just confirming that having a rich diversity of plants in your diet is good. And we still believe that hitting a target of 30 is achievable and seems to be a reasonable one to go for. 30 different plants, including different types of nuts and seeds, herbs and spices. Trying to eat the rainbow, so you're getting all the different chemicals from these polyphenols, these defense chemicals into your diet. Having regular fermented foods, which gives you your gut microbiome a bit of a boost in ways we don't totally understand yet.

• 10:07Speaker 02

  And you probably need to have three little portions a day of ideally different ones to really optimize it.

• 10:15Speaker 00

  And actually Nicola, I was going to ask, because that's a lot about feeding the good bugs, what do I want to eat less of to try and like push down those weeds, you know, the bad bugs that we've been talking about?

• 10:26Speaker 01

  But again, I don't think there is one single food that is bad for you a priori, unless you eat too much of that bad food. So, you know, little amounts of bad foods here and there is not a big problem. I think it's much more the advantage of eating a lot of healthy foods and a diversity of healthy food and pushing down the bad bugs. So this is the first thing. Of course, you know, too much red meat, of course, is a problem, clearly, but we shouldn't feel bad in eating every now and then the food.

• 10:57Speaker 02

  You can have the occasional pizza, can you?

• 10:59Speaker 01

  Absolutely. I have to.

• 11:02Speaker 00

  And Tim, you mentioned about fermented foods. I think this is something that's still for a lot of us is not very familiar. What fermented foods are in your fridge?

• 11:11Speaker 02

  Uh, my wife says too many.

• 11:14Speaker 01

  You can smell that probably.

• 11:15Speaker 02

  She can smell them, uh, yeah, from a long way away, uh, especially if I've had been home for a while and been doing a bit of my own fermenting. So I've got, always got yogurt and I've always got kefir, kefir, which is fermented milk. I've just made a batch of uh, water kefir, which also called tibikos, which is like a court, sort of like a fizzy drink.

• 11:40Speaker 01

  No kombucha?

• 11:42Speaker 02

  I haven't made any kombucha at the moment. I've got my blob is in the, in the fridge, which looks disgusting to anyone who's not an aficionado like myself. I've got uh, kimchi, I've got um, some kraut in there. I've got some miso paste. Um, I've even got some uh, garlic in honey, it's fermented in honey, uh, which I use in salad dressings. I've got usually a whole range of smelly cheeses, uh, lots of different ones. And I also got my sourdough, uh, mother, and I've just made some sourdough, uh, yesterday, actually. So that's, that's on the go. So I've got a, a full range. And so, yeah, I, I, I'm never

• 12:27Speaker 02

  short of fermented foods. So that's, that's, I always try and get my three portions in.

• 12:33Speaker 00

  Amazing. And might you have a new fermented recipe, a simple one that someone listening to this could follow?

• 12:41Speaker 02

  Oh, um, it depends what you've got, but it's a very practical one. So often I find I have to go away on trips. I've left my fridge with vegetables in the bottom shelf that are probably going to go off if I don't do something with them. So I call this my fridge raid ferment. And whatever's in that lower uh, compartment, except over genes, which go horribly soggy. So the things, whether it's carrots, uh, sweet potato, cauliflower, broccoli, onions, tomatoes, uh, garlic, doesn't really matter, a bit of cabbage, and even it's, you know, a quarter of it. You chop it up into uh, small chunks, half an inch

• 13:25Speaker 02

  thick, try and get it fairly even, stick them in a bowl, uh, weigh them, then do some maths and calculate 2% of that weight. And you put that as salt and you throw salt on it, massage it in a bit until it's really worked into the veg, stuff it in a jar, uh, which, which has a lid and ideally a little valve. So you've either got to burp it every day or the valve will do the trick for you. And leave it for five days while you're away. You, you leave it out in room temperature and that will be bubbling away and fermenting. And you should, when you come back, have a beautifully preserved fermented uh, fridge

• 14:09Speaker 02

  veg. And uh, it's uh, yeah, that's an easy way to start and uh, very good for the planet.

• 14:17Speaker 00

  I'll leave you with one final thought. What if there was one simple habit that when repeated could change how you feel for the better? I'd like to tell you about something that I do daily for my own health. It's called Daily 30, the gut supplement developed by our scientists here at Zoe. Daily 30 is made of over 30 handpicked plants, including seaweed, fungi, and different types of fibre. It's a source of plant protein, omega 3, and vital minerals. You simply add a scoop to any meal once a day to support your health and increase the plant diversity in your diet. And unlike synthetic supplements, Daily 30 actually tastes great. It's designed to be enjoyed because when a habit brings you

• 14:58Speaker 00

  joy, you're far more likely to stick with it. So next time you feel like your plate is missing extra plants, do yourself a favour, try Daily 30. It's a delicious and healthy habit that you'll feel good about and one that your gut will definitely thank you for. By the way, whenever we talk about Daily 30 as a good source of fibre, we're required to say that it contains four grams of tuttle fat per serving. Obviously, that's all amazing healthy fats from plants. So order yours today at zoe.com/daily30. See you next time.