ZOE Science & Nutrition - Recap: Simple steps to great gut health | Nicola Segata & Tim Spector

Episode Date: June 10, 2025

Today we’re zooming in on our gut. It’s our favourite topic here at ZOE and for good reason! Research into the microbiome continues to reveal just how astonishingly far-reaching its effects are. From immune function to metabolic health, and even mental well-being, your gut is quite literally at the centre of everything!. I’m joined by microbiome experts Nicola Segata and Tim Spector to recap how we can nurture and take care of it in our daily lives. Unwrap the truth about your food 👉 ⁠⁠Get the ZOE app⁠ 🌱 Try our new plant based wholefood supplement - Daily30+ *Naturally high in copper which contributes to normal energy yielding metabolism and the normal function of the immune system 📚 Books from our ZOE Scientists: The Food For Life Cookbook by Prof. Tim Spector Food For Life by Prof. Tim Spector Every Body Should Know This by Dr Federica Amati Free resources from ZOE: Live Healthier: Top 10 Tips From ZOE Science & Nutrition  Gut Guide - for a healthier microbiome in weeks Have feedback or a topic you'd like us to cover? Let us know here Listen to the full episode here

Hello and welcome to Zoey Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today we're zooming in on our gut. It's our favourite topic here at Zoey, and for good reason. Research into the gut microbiome continues to reveal just how astonishingly far-reaching its effects are. From immune function to metabolic health and even mental well-being, your gut is quite literally at the center of everything.

I'm joined by microbiome experts Professor Nicholas Agata and Tim Spector to recap how we can nurture and take care of it in our daily lives. Let's start at the very beginning and, you know, Tim, why should we care about the microbes in our gut at all? Well, although it's not a question of life or death, they are pretty much crucial for so many processes in our body. And I think what we're realizing is just how crucial they are for our immune system, because we've assumed that, okay, microbes are there to digest our food, which is true. They have thousands of chemicals that our body doesn't have itself in order to break

down food and extract the nutrients. We know that from mouse experiments, if they take away the microbes, make them sterile, those mice have to eat like 30 or 40 percent more every day just to stay alive because they don't have those careful processes. So life would be a struggle, but I think it's the new science is telling us that the immune system is the key to why we need a gut microbiome to be healthy because 70 percent of our immune system is in the lining of our guts and that's interacting with our microbes. So our microbes are essentially mini pharmacies pumping out chemicals that are interacting

with all those cells, those immune cells, and that's priming them so they know whether to attack things or to defend things or just to get it right. When it goes wrong, that's when you get food allergies, that's when you get autoimmune diseases, that's when you don't detect early cancers, and that's when you don't repair some of the processes of aging. So increasingly, we're expanding our view of what the microbiome does from a rather limited idea of, oh, it helps break down food and it's quite useful for our energy balance and our metabolism to a much broader idea of what they all really do, which we're starting to see in some areas like cancer and immunotherapy, et cetera, et cetera.

So I think that's why everyone needs to know about the gut microbiome and everyone really needs to know that it's not just about how we break down food. It's absolutely crucial and that explains a lot of the Western epidemics of chronic disease that as we've lost our gut microbes over the last 50 years, we've also gained all these diseases, all these allergies, all these immune problems, and we're facing this pandemic of ill health. So, by understanding the gut microbes, we can get back on track and really start to get back to our origin, where our set point of health. And to do that, we need a healthy set of gut microbes. And I will actually also add the brain, no, because there is the gut brain axis. Microbes are connected with our brain through chemicals, through neurotransmitters

that are produced. And so there is a connection between our gut and our brain. So even more functions. Yes. They actually produce the neurochemicals to make these key differences between us being happy and sad, depressed or anxious. And we're only just discovering all those intricacies there. So yes, they're key to virtually all the bits of our body and we ignore them at our peril. I always love hearing Tim and Nicola talk about this because you come away just thinking how amazing it is and how important it is.

And of course, how new it is as well. And I think we can explore a bit today, sort of the things that people are coming and starting to understand. Before we do that, just can you help us to understand how many different bacteria and other microbes are there in our gut? Well, Nicola might have a different number to me because everyone you ask can't really give you an exact figure for this, but in total numbers there are hundreds of trillions of bacteria, but there are also another related species called archaea, which we don't talk about much because we don't know as much about them. Then we've got five times as many viruses, little mini viruses called phages, which eat the bacteria. And within all that lot, we've got fungi, we've got yeasts, and we've even got parasites,

which we're starting to find are of great interest and some of them are even healthy. So we've got this menagerie, if you like, it's like a jungle out there of lots of predators eating each other, controlling each other, struggling for survival, little ones, big ones, fat eating ones, protein eating ones, sugar eating ones, fiber eating ones, and they're all in these ecosystems struggling for survival. And as they eat the food, they're pumping out all these incredible chemicals that are used by our body, our immune cells, and our health. So you've got to try and envisage this as this living community of microbes working together and totally dependent

on the food that we give them. And I think that's really important, which sets their environment. And if we get that wrong, then environment shifts and those populations shift. Just like, you know, if there's no rainfall in a forest or you spray pesticide all over it, you're going to get a very different environment. Everything from the tiny insects to the lions and the big beasts, they're all inside our gut and everyone has a very different community. Could we talk about what's the actionable advice you would give to somebody listening to this saying I'd really love to improve my good bugs.

I'd really love to improve my good bugs. I'd really love to shrink my bad bugs. What's the key advice that you would give both of you? Well, I've got five simple rules really to improve your gut health. First, try and eat a diverse range of whole plants. And we think at the moment, the optimum is around 30 plants. We're doing some other studies to see if that's still true now with these new tests. But 30 different plants a week is what people should aim for. Not a problem if you don't always make it, but aim to get it right up. Currently people have about five on average, right? So there's a long way to go.

The second is eat the rainbow, try and eat colorful plants because of the polyphenols, these defense chemicals in them, which our microbes eat and is a source of energy, which we didn't know that before. And that includes all kinds of bitter foods as well, extra virgin olive oil, for example, nuts, seeds, dark chocolate. Then fermented foods, having regular, small amounts, regular fermented foods has been shown to improve your gut microbes and improve your immune function.

So dampens down those inflammatory microbes. And fourthly, give your gut a break. We've talked about time restricted eating. If you can eat within a 10 hour window or if you can't do that, a 12 hour window at least, you give your microbes a rest overnight. That helps them and make them more efficient. And finally, don't poison them with too many chemicals

from ultra processed foods. Because ultra processed foods have a negative impact on your gut microbe in ways we're still understanding, but things like sweeteners, emulsifiers, preservatives, et cetera, et cetera. So they're my five rules. And of course there are other ways, the environment, aren't there, of course?

Yeah, these are the great general rules, but I think in addition, the challenge is to understand what it personalizes to you. And that is what we are trying to get from the data because maybe for you the best is to understand what it personalizes to you. And that is what we are trying to get from the data because maybe for you the best is 30, for some 30 different vegetables, for others maybe 20 or 40. So that is the personalized part of it

that can add a big added value to that. And can I wrap up with a couple, we had a lot of questions from the community. I think we've managed to answer some of them. I want to pick a couple that we haven't hit here that were specific. So I've got both of you, which is rather special to have you physically in the room here. So one question was like, how rapidly can I damage my microbiome? And we had a lot of questions saying like, I've gone on holiday, I've eaten really terrible food for a week, lots of all the things that Tim tells me I shouldn't done.

Have I wrecked my microbiome? Will my bad microbes have doubled during this period in a week? How worried should people be? Well, I think you should be very worried if you go on holiday and then you get sick and you have to take antibiotics, for example. that will ruin the most of it. Otherwise, I think we all go on holidays and we need to eat differently. So it's not a huge problem if it is for a week or so because there is these dynamics of the microbiome, you can then go back. And I think in general, if you travel or go on holidays and you have a diversity of food, wherever you are, it's also going to improve. And I think in general, if you travel or go on holidays and you have a diversity of food wherever you are, it's also going to improve.

So I think there is this memory of the microbiome that unless you continue with antibiotics or very wet food for a long time, it's unlikely you will disrupt it completely. The caveat might be if you go on a junk food holiday and you only eat junk food for say like 10 days. There's a meatless meal. And you have zero fiber, no diversity, having the same meal. And this is the experiment I put my son

through a few years back when he was a student. So for 10 days, he had only chicken nuggets or a Big Mac and Coca-Cola. And he lost 30 or 40% of his diversity in that time. And I'm afraid to say still hasn't regained it. So I think, so the caveat is don't go on a purely junk food, zero fiber holiday because your micros may take much longer to recover. And my takeaway from this is, and it's one of the things I think that you and Sarah and other people talk a lot about at Zoey is like, it's fine to have treats, it's fine to add some stuff on top. So in the sense in the holiday, by all means have your pizza and your ice cream, but you'd

like to make sure you're still having some food through this that's going to sort of support your microbiome. Because it sort of makes sense, right? If you starve them for 10 days and they all, they like reproduce very fast, right? Nicholas, like once an hour or something like this, right? You can see that's a lot of generations with no food, which I guess I sort of think of as a, well, that's quite different, right? Than saying, okay, I'm going to give a lot of stuff that's maybe good for my bad

microbes, but I am still providing some food for the good guys and we'll get them back after the holiday. Is that a sort of practical way to, that's like being my practical approach to holiday now? Yeah, give them a minimum diet. But in a way, the people should be relaxed. If you've got a healthy gut microbiome, you can afford more leeway than someone who's got a really sick microbiome. And I think that's the more leeway than someone who's got a really sick microbiome. And I think that's the key. If you've built up your gut microbes well, you can have the odd excursion with junk food and you'll bounce back.

But if you've got a really poor one and you go overboard, then you're really in trouble. But yes. And I think the funny thing is that I also found my taste has changed a lot. I still definitely want gelato. That comes up quite often on these podcasts, but there's a lot of junk food that I used to eat

that actually now sort of seems quite disgusting, having switched away from it for a prolampy. And you realize you sort of got addicted to this stuff. And I know we'll talk about that on another podcast. Final question, because this came up interesting, it was like the top question. Is there any data about whether taking painkillers regularly can negatively impact the gut microbiome? painkillers regularly can negatively impact the gut microbiome?

Well, we know, as Tim mentioned, that probably the two main worst medications are proton-piped inhibitors and antibiotics. But all the others are not positive for the microbiome for sure. So I don't think we have a lot of data from Zoe on painkillers, but also from other studies we see that they are not good for sure. Not at the level of antibiotics and protoparty inhibitors, but definitely something to keep an eye on. For painkillers, we know that they've studied paracetamol quite well, and we know that the reason they don't work in some people is just because they don't have the right microbes. So it's quite possible that some of these side effects people might get might also be

related to the gut microbes. We simply don't know enough, but we do know that at least 50% of all the drugs people take are interacting with your gut microbes in some way. And we have to be a bit cautious that all of them could be doing damage or interacting in some way and we have to be a bit cautious that you know all of them could be doing damage or interacting in some way so it's an area we need to do much more research on. But the example I did it was just because there are very few examples that are documented and so you know with the variety of drugs that we can take and the rest of our microbiome it's another line of research that should keep us busy. I think Nicola, you feel like your career is set

for the rest of your years, I feel, with this, like, is this right? We still have a bit of work to do, yes. Yeah, absolutely. And, you know, we did some work on cancer therapies and immunotherapy, and certainly the state of your gut microbes is probably the number one factor that determines whether you're gonna respond to immunotherapy and cancer.

And so increasingly, I think, when people are put on drugs, physicians are going to have to learn more about the gut microbiome and take that into account as we start to balance these things up. Because it really, in some cases, is a matter of life and death. Yeah. Or, if you're looking for another episode to listen to today, why not try a popular episode of ZOE Science and Nutrition like What to Eat to Avoid Osteoporosis, How to Prevent Heart Disease or Mushrooms as Medicine. Search for them on your favourite podcast player.