Eat This Way for Better Gut Health | #1 Gut Microbiome Doctor Tim Spector

Today I'm joined by Professor Tim Spector, an award-winning scientist ranking in the top 100 scientists worldwide. He's a bestselling author, medical professor, founder of ZOE, and the leading expert in the gut microbiome. He's here today to share groundbreaking research on how the gut microbiome impacts your health, the connection between the gut and your energy and mood, and the science behind how to improve inflammation, gut health, and metabolism. Dr. Specter, a lot of people don't have a full appreciation for how much food can impact both their short and long-term health. And I'd love to start out with, how does what we eat signal to the brain, to the nervous system, and the immune system that impacts every aspect of our health?

Uh, hi Brigid. Yeah, great, great question. Um, well, we didn't really know the answer to this until very recently when We've started to understand the gut microbiome, which is probably the main link between the food and our health. It's this whole community of these microbes, which are essentially mini pharmacies pumping out chemicals in response to the food that we eat. And those chemicals then go on and have these really key interactions with perhaps 3 main systems in our body, our metabolism, our immune system, and our nervous system. And we are sort of each year learning a little bit more about how this works. 'Cause we used to think it was all down to one chemical in the food, for example, that had this direct effect on our brain or in our blood. But now we know it's so much more complicated that It involves thousands or tens of thousands of chemicals all interacting with each other. And we also have only recently worked out how important the immune system is to this whole business. 'Cause we thought immune system, what's that related to food or nutrition or health? You know, that's just allergies and things. But no, it's absolutely essential in that most of our immune cells are lining our gut and they're there for a reason. They're there really to sense what our outside environment is doing. And in a way, that's the role food has in this whole process. So yeah, you can explain pretty much all the effects of food in our body through these three main mechanisms, the three main systems controlling our metabolism, which is in a way how our body manages energy through our mitochondria, through regulation of how much energy each cell's using in different parts of the body, how our nervous system is working because most of our, our second brain is in our gut and there's this huge channel between the gut and the brain that is mainly from the gut to the brain. So it often tells the brain what to do and think and behave rather than the other way around. And then finally, we have all these immune cells lining our gut, which are picking up these chemicals that the microbes produce and will make them behave in a certain way, either to underreact or overreact or be just right in terms of the environment that they're facing. So the food we eat can send the correct signals to our body or the abnormal signals. And it seems to happen in this way that both affects our short-term things like mood and energy, but also long-term it can be setting long-term stress in the body that causes heart disease and accelerated aging and cancers further down the line. So really important that everybody understands this crucial way in which how food affects our body. And it's through this, basically this new organ in our body that we are just beginning to understand.

It's so fascinating. And when we were at Eudaimonia, we were both at Eudaimonia together, and you had said something so eloquent stating that these are mini chemical factories, essentially, your gut microbiome, the microbes in your gut that are changing your food into other metabolites that then feed trillions of cells, that if we take care of them, then they take care of us. And I feel like when you talk about how prior to the research on the gut microbiome coming out, there wasn't an understanding of how comprehensive it was, how holistic and interconnected the body is, and how much it's taking our inputs, which is the food, and then creating these messages or signals, as you call them, that then impact anxiety and depression that are manifesting in the brain, or, you know, are pain that's happening in joints or other symptoms throughout the rest of the body. Is that right?

You're right. It sort of paints a much more holistic picture of health and nutrition than we'd been led to believe because the previous sort of ideas, you know, coming on from the war and really deficiencies and vitamins, it's all about individual ingredients, individual chemicals. How those might be interfering with the body. Whereas to really embrace this new science, you've gotta take much bigger picture and say, well, on their own, none of these are really important. It's what's happening overall. It's the overall food, it's the overall state of the gut, the overall state of the immune system. I think that's a really important shift in, in our thinking here as we try and move ourselves away from the old system, which largely failed people, onto something that is much more sustainable long-term and generally a much healthier concept rather than always trying to plug a hole with one wonder ingredient or one amazing mineral that's gonna transform your body.

Yes, I couldn't agree more. And so if we know that you can eat foods that help to improve the microbes and create more thriving microbes, then the opposite is also true, correct? You talk a lot about ultra-processed foods and how, how harmful they can be. Can you explain for people who may not understand outside of just nutrition as calories in versus calories out, um, how ultra-processed foods can have the opposite effect?

Yes, so quality of our diet is really important rather than quantity. And by quantity I mean we need to move away from defining food by macronutrients and calories, which is the way we've traditionally done it in the past, which served its purpose 40, 50 years ago, but no longer really adequately describes food in terms of its effect on health. And so we need to understand all the things that these so-called ultra-processed foods, I prefer to call them high-risk processed foods because ultra-processing isn't really a nutritional term, but we sort of all know what it roughly means. It's those really highly artificially made foods that have been enhanced in some way that you, you couldn't do in your own kitchen, but contain either harmful additives, uh, they're hyperpalatable so that you overeat them because they've been made with a blend of chemicals to, um, uh, override your normal fullness signals. They have a structure that means you, you can eat them super fast and deliver calories really fast to your body in a way that again, you don't find in nature. All these things. But the main reason they upset the gut microbes is through two main mechanisms. One is the additives that are put in there to create this fake food, which would include things like artificial sweeteners, which are basically derived from the petrochemical industry and our body and microbes aren't used to breaking down 'cause we weren't evolved to eat petrol basically. And gasoline, you've got emulsifiers in there which glue your food together but also glue your microbes together. You've got other gums and, anti, and things that preserve your food for long periods of time. They will also have negative effects on the gut microbes as well. So you add that and you got various colorants and flavorings that we still don't totally understand how they interact with our gut microbes, but they're generally not good. You've got all that list of potentially harmful additives, Then you've got the fact that generally they're stripped of fiber. So because they're created to make you eat many more of them than you would normally do, you do that by taking out the fiber and making them absorb really quickly. That means that essentially if you're eating diet mainly of those foods, the nutrients are not reaching your lower part of your gut at all. And so they're effectively being starved of nutrients. They're not getting fiber. They therefore can't make all these great chemicals that really help the rest, those other mechanisms we talked about like the immune system. So it's both harmful additives and it's deprivation through a major fiber lack that's causing it. And of course they make you overeat by about 25%. And that has consequences for your overall body because building up all the fat cells itself causes inflammation. And that inflammation is sensed by your gut. That the gut lining is inflamed, that send signals to the brain that can make you depressed as well as increase your risk of many other diseases. So it's, again, it is complicated. It's not just one factor, it's a whole group of them. And it's the total opposite to eating whole food, which is there to nourish and help your gut microbes do the job that, you know, they've evolved to do for millions of years.

And so in the research that you've done, which is vast, you are one of the top 100 scientists and one of the leading nutrition scientists in the world. And in your research, you found that when you take people away from these foods, you change their diets to a more whole foods diet that's based on the ZOE model that you've created, that you notice specific symptom improvements before actual changes to the lab markers that you're looking at or the gut microbiome. Can you share what are these 3 symptoms and why is it so significant that the symptom improvements happen before the lab changes?

Obviously when we started these ZOE studies back about 8 years ago, we were doing the largest, dietary intervention studies in history, really. And no one had really looked at many of the things we were looking at. So it wasn't like people had looked and not found it, they just hadn't had sufficient numbers. The average nutrition study, as you know, usually based around 20 students in a nutrition unit, you know, in a college somewhere, getting credits for taking part for a few weeks. And very young, very healthy, and just usually measuring bloods, things like blood lipids or something like that. So the idea of actually following people intensively and finding out how they were feeling or getting a whole range of symptoms was really unknown until we did these studies. The first very basic study we did, 1,000 people, giving them identical meals, showed this tenfold difference in blood parameters, in blood sugar or blood fat. That was the PREDICT-1 study. Then subsequent studies we did with larger numbers of people, we changed their gut microbes from, towards a healthy state, either by mainly by firstly by changing their diet, giving them our prebiotic, our Daily 30, which is 34 freeze-dried plants, or asking them to take fermented foods 3 times a day. So we did, these were like 3 vast citizen science projects, you know, involving hundreds of thousands of people. And we asked them to track how they were feeling every day. And it turned out that within a week, half of, approximately half of the people in the active arm of these studies reported having an improvement in their mood, their energy, and reduced hunger in that time. And these are all brain effects. That really I think doctors and nutritionists were not trained to ask about. It just wasn't in our training. And this brought home to me how important this gut-to-brain axis is and how sensitive our guts are to these feelings. So that's why, we think it's particularly important that even before we saw changes in inflammation or a drop in cholesterol levels, the brain is much more finely attuned to what's going on in your gut and your body. And I think we just need to start listening to our own bodies, but also as health professionals start making having these sort of discussions with our patients because I think people don't realize this really close link between what you eat and how you feel. And even symptoms like fatigue and loss of energy, people have just said, well, that's just life. They've never linked that to, well, maybe if I just went on the Zoe diet or I just took my, some prebiotics, I could change that. And it's only when you start thinking about it and start thinking, how do I feel 3 hours after a meal, that you can, you can make progress. Because if you don't think about it, if you don't ask it, the doctor doesn't ask it, you, you know, your, your nutritionist isn't into that short-term element of it, you, you could miss that huge benefit and, and not and be focusing on things like blood sugar or weight or some of those more traditional parameters that we're all more comfortable with. So to me, that's been the revelation of, you know, particularly in the last year as we're getting some of these big results back, is how important that self-reported feeling is that, you know, in the past we might have dismissed as chance or placebo effect.

Yeah, I couldn't agree more. So this is so fascinating to me because of how people are conditioned to think about nutrition, where if they're not losing enough weight fast enough, they're like, oh, this must not be working. And so it reframes every way that we think about food to say, just because you haven't lost weight yet, or that you haven't improved your blood sugar markers yet, doesn't mean that physiological changes aren't actually occurring. And that if we can pay attention to how you're feeling in response to changes that you're making, it's a signal to your body that you are on the right track, which I think is point number 2, is the importance of being able to be in tune with your symptoms and being able to identify that as progress. And point number 3 from that to me is that when we think about inflammation, most people attribute it to joint pain as being that primary indicator. But as you've said, if we start to shift in thinking about mood swings, depression, and fatigue as primary signals that inflammation is happening underneath the surface, then you can understand how intervening and improving those symptoms may actually prevent you being on a downward spiral that leads to the onset of inflammatory conditions 10 years later, because we know that things like type 2 diabetes and different autoimmune diseases and cancer and Alzheimer's disease, that they don't just— it's not a flip that switches where you're diagnosed and, and that's the same time that the onset happens. It's not an overnight process. It's decades in the making. And so if we could be more in tune with our bodies to say, wow, these, these things are shifting, because you never know what you prevent when you prevent it. That you're able to then identify, oh, this could be me actually stopping chronic disease decades before actually having the onset of a diagnosis in my doctor's office.

Yeah, no, that's absolutely right. I mean, I used to be a rheumatologist, so I was dealing with autoimmune diseases, people with major inflammation, and it was never really clear why, so many of my patients, we knew why they were so tired 'cause they said had very high immune markers in the blood of inflammation. They were also depressed and we thought that was just related to having arthritis, but turns that wasn't the case. It was this constant level of inflammation in the blood. And I think what we're seeing in these sort of community studies where, you know, perhaps 30 or 40% of the population are suffering from tiredness without a diagnosis, they really are the very, very early stages of a chronic condition. And we don't really have the sensitive blood tests to always pick it up. Sometimes you might, but we still lack those. So getting in tune with this concept of recording things like fatigue and tiredness and seeing how it changes over the day and before and after meals, I think it is really important because it, it, it will tell you, give you insight into what's happening in your body, what's happening inside your gut, how your immune cells are reacting. And to me, that's one of the big insights. And we know that inflammation in the brain is now, does occur. There are immune cells in the brain. We didn't think there were, but we now know there are. And probably a state of not only low mood, but when that shifts onto more serious depression, that is just picking up these signals from the rest of the body and interpreting it wrongly in a way. So if you can change the signals from your gut, you can change your food, you can really change everything about yourself that is so much more than weight and a blood test.

Yeah, it's so profound. And I'd say that your research has validated so many of the experiences that I've had both personally and in my practice where we've had about 30,000 people go through a program. That I've been running for 5 years called the Blood Sugar Reset. And the top 3 symptom improvements in the, the data that we've been tracking are energy, mood, and craving. So it's not the same as, as hunger that you're reporting, but when I heard you say that at Eudaimonia, that that is what your research has found is those 3 improvements, I was like, wow, this is exactly what we're seeing as well. And we're not publishing, you know, peer-reviewed research studies in the findings that we have, but this is also something that we're seeing across the board. And it's my own personal experience 20 years ago, I was diagnosed with narcolepsy. I have the autoimmune version of narcolepsy. So it's a connection between chronic fatigue and autoimmune. And when you're in this, my parents then took me to a functional medicine doctor 20 years ago. But when I didn't want to change my diet, I just wanted to take the pills that they were recommending. Because when you're so tired, it's part of your identity and you're like, no, this just is how my life is, as you said. And you don't have the energy to make the changes that you need that actually can help to get you out of that cycle. And it leads— when you're so fatigued, you're like, I just want to eat all the sugar and the carbs and the other food. And you kind of like make it as an excuse for why you, you can't take care of yourself. And I think for people to be able to understand that when, even when you have inflammatory-based conditions, that the fatigue is a manifestation of an underlying core imbalance, and that when you can change one imbalance, it can lead to improvements in many different symptoms that are manifesting in different ways that are all originating from inflammation, is what I'm hearing you say.

That's right. And the link obviously with blood sugar is interesting, so that we showed that, um, people who get a a big spike in their blood sugar or their triglyceride levels also have a spike in, a short-term spike in their inflammation levels. So it's causing a stress, a short-term stress on the body. And that can have a short-term effect, but it also builds up over time to cause more long-term changes to the immune system. You've got, you know, these, all these related mechanisms affecting you. You know, some are inside the gut, some of them are, you know, just eating a sugary snack that, you know, may not have as much to do with the microbes, but the immune system is the common denominator here. So it's really important that, you know, we start to embrace this new science and see how it can affect us all because, Yeah, we've all had that. And you know, you talk when you were very ill, but in a way everybody experiences that sometime. If you've had a sleepless night, your brain feels very inflamed, you're very stressed. Just like when you're ill, you reach for the sugariest, most horrible breakfast thing to eat. It's a sort of survival mechanism that's gone wrong. And I think it's, you know, so we can, I think we can all relate to this. It's just some of these things are short-term, some are long-term, but it's great how this, I think the science is coming together now to explain it. And hopefully we've got some of the tools in place that we can, you know, start helping people in this early stage where there was nothing before because, you know, we just talked about blood tests and tablets.

Mm-hmm. I know that's why your work is so important.

Yeah. And, and food is such a great treatment for this, you know, that, you know, people can't, you know, I've seen some families on very high processed diets and then, you know, within a week, suddenly the whole family's mood has changed. You know, they, they just realize that, They're different. They're not having to have naps in the afternoon. They are talking to each other, really different. And I think this is, yeah, what makes it so exciting and so immediate that you can give people advice. And if you track those elements of it, you get immediate bonuses, which you don't have to wait and see them again in 3 months to see it. That's what's so great. And that if you tell them this will happen, then that is self-motivating to continue. So it makes so much easier, I think, to make these dietary changes if they can see positively what's happening and you've warned them as well.

And for us, we see it even in people that are self-identifying as eating healthy, right? Because I know that you're doing work in like the documentary that you're working on that is people who are eating like not healthy foods. And then they're seeing these changes in a short period of time where they have the lift in their mood and other things. And you might also experience this with Zoë, because I'm sure that people who are signing up for Zoë are more health-conscious consumers. But for us, like our community, they're reading their labels for the most part. They're like eating pretty healthy, but they're eating like rice cakes and something that's triggering more of a blood sugar response that even just shifting to a more blood sugar-friendly diet can make huge transformations, like you said, in a very short period of time. I'm interested, what is— if you were to explain the number one goal for supporting a gut microbiome, given everything that you've shared about how the brain is always receiving signals from the microbes and everything the microbes are releasing, essentially, that can lead to then malfunction or optimal function. What's the number one goal for supporting a healthy gut microbiome that you found in your research?

Well, we keep adding guidelines for gut health, so obviously it's the number one question I get asked, you know. Um, um, and so we've now got 8 sort of general guidelines we can— we may get time to get to, but number one for me is is still eating a wide diversity of plants in your diet. And we, we've selected on at least 30 a week as our goal, which includes, you know, fruit, veg, nuts, seeds, herbs, spices. It's, you know, not as hard Even coffee is a fermented plant, so that counts. That diversity is probably the number one thing that feeds your gut microbes, 'cause our research has shown that, you know, how the importance of giving prebiotic supplements, for example, when we use our Daily 30, did better than a probiotic. Because you don't know, everyone's very different in what their gut microbes are. You've gotta give food for everybody. It's a bit like going to a zoo and only having one type of food for all the animals. You wouldn't do very well. So you want to go out with a really rich basket and hope that you can keep most of them alive. They'll find something in there to eat. It's that sort of analogy I think is really important. 'Cause some of our microbes are really fussy. We found a bug called Lawsonia bacter that only eats coffee, for example. And it doesn't eat tea. The one that likes tea won't like coffee. So you've gotta realize you've got all these fussy children or animals inside your gut. So give them breadth. That's the number one. And if you do that, you will naturally get your fiber levels up above, you know, the recommended levels of over 30 grams a day. So you don't have to count that. And I think that's the number one message, I think. And it doesn't matter if you still eat a bit of meat, have a bit of dairy. Our studies have shown that the very top people, you know, even if you did a bit of meat and dairy, you can still do better than the best vegan, for example, but only as long as you're eating lots of plants. And I think that's an important message. It's not about excluding stuff, it's about including it and adding it to your plate.

Which is an entirely different way of, for people to think about nutrition in many ways. So embracing diversity is the number one goal for gut health. And you've published research on how having more than 30 plants per week is what's associated with the highest level of diversity. And I also heard you explain even from a coffee standpoint, but also I think the analogy that you gave around kale was really beneficial where you were like, you don't just need to eat 5 cups of kale every day because there's microbes that love carrots and onions and other foods that I think is so helpful to understand. Like we wanna be fueling all of these beneficial microbes and that's how that we do that through the diversity. When you're talking about this, can you explain the difference between prebiotics and how they work as fertilizer and how these findings have changed what you might have previously thought about probiotics being the most beneficial?

Sure. It's worth just defining what they are. So—

Perfect.

Probiotics are essentially live microbes that are beneficial believed to be beneficial for human health that exist either in capsule form that you might get in the health store or actually in food where they naturally live and replicate and you eat them with the food like in a yogurt or a kefir. Then prebiotics. So I think of probiotics as like microbial seeds So you are introducing healthy species into your gut and it was believed that's how they work by seeding into your gut and then reproducing. And so you'd get more healthy microbes or they'd have some knock-on effect. Whereas prebiotics were often disregarded in the past. They essentially were fibers that are fertilizer for your microbes. And there wasn't much interest or research behind them. The big companies didn't really go for them because they filled you up and they didn't make you eat more. And there were ones that were sold were often rather artificial, like inulin fiber, which would look like just a chemical powder. It wasn't very appetizing. And they were the two main ways you could help your gut microbes. And we did a study to see which was more important. And they both, we did over 350 people, big randomized controlled trial by nutrition standards. We had a placebo group. And over the course of 6 weeks, the one on the prebiotic we'll be using our own Zoe Daily 30, which is a mix of 34 mainly freeze-dried plants, but big variety of them with 5 grams of fiber per scoop versus a probiotic, which was one of the leading ones, Lactobacillus rhamnosus, which has been shown in a number of trials to work. They both worked on the gut microbiome, but we got 10 times more effect on improving good microbes with the prebiotic, which is very broad, than with the very narrow probiotic seed. And I think that was to me really interesting 'cause there haven't been very many comparisons at all in the literature, one versus another. Probably for commercial reasons. They didn't want to compete or see they weren't effective. And it sort of makes sense because our microbiomes are very diverse. You know, we're all individual. And so a probiotic may work quite well in some people, but not in others. And when you put them all together, sometimes they interfere with each other and those strains can actually counteract each other. But if you just put the fertilizer out there, basically everything's gonna grow in, you know, 99% of people, which is what we, we saw in our trial. So it, it's sort of logical, but until that study came out, we, we didn't really know it. And I think it's, it's changed my view about this. And interestingly, it may be that fermented foods work better than, these probiotic capsules that you get in health stores, probably because you're getting 20 or so different microbes when you're ingesting them and you're getting larger amounts. So I don't wanna dismiss the probiotics in fermented food, which I think are also helpful for your gut microbes, but maybe act in a different way. And all the evidence suggests they probably don't work in the lower part of the intestine. They work higher up in the small intestine and probably a bit like tickling the immune cells in the small intestine is my guess where, how they're having their effect. So they're not overwhelmed by the trillions or billions of trillions of microbes in our colon, which would be very hard to influence, if you like, if you are, you know, fighting alone in a bit of yogurt against that mass of microbes. So we are learning that the fermented foods have this potentially immune effect, anti-inflammatory effect, whereas the prebiotics have a general regenerative boosting effect on our good microbes.

And the prebiotics help with, 'cause the prebiotics serve as the fuel for your microbes, which help them with the release of more of those anti-inflammatory signals like short-chain fatty acids. Is that correct?

Yes. So the more good microbes you've got, the better you're able to, produce these helpful chemicals that help your immune system and your nervous system. And so you're, in a way, you've got more of a toolbox to be able to dismantle the fiber that comes in and extract the good stuff and produce the good chemicals. I think that's the way to look at it. Whereas if you've got a very restricted gut microbiome, you may not be able to digest the food well enough to get much of these short-chain fatty acids that help the immune system. So it's all about having, you know, the biggest toolbox, the most versatile set of chemicals in these sort of mini pharmacies. And so you've gotta really supply them with everything they could possibly need rather than just giving them selective ones that you are just guessing is gonna be good for them. That seems to be the best approach at the moment. And that's why we see these very strong correlations in all populations between the diversity of plants people are eating in these populations and their gut health, which is far bigger than any other factor.

And I think it creates an opportunity even for people who let's say are dairy-free because they can't tolerate dairy very well. And they're drinking almond milk, eating almond yogurt, eating almond-based cheeses, that you think about how you can even diversify your nut milks and the different sources of nuts that someone could end up just over-consuming almonds when they've removed a different portion of their diet, let's say.

Yeah, no, once you realize how important diversity is, then you start to use it in all aspects of your diet really. And we move away from this very defensive idea we've had, you know, started perhaps 20 years ago, particularly from people with intolerances and allergies to keep excluding stuff until you are safe with just a few plants that you're eating. You know, it's looking like that is a very bad long-term strategy. May help short-term. So short-term you might have got some relief 'cause there might have been something upsetting you. But looking back at it, it was probably the processing in these other foods rather than the actual food itself in many cases. Obviously, you know, everyone's different and everyone's got their own stories. But this, you know, relentless exclusion of foods and in a way inciting anxiety into people's diets has led to them getting more and more restrictive, which meant they get a less healthy gut microbiome, which meant their immune system continued to get weaker. So we need to get that back and reverse those big effects and think much more long-term about our health now that we know how important it is for the rest of our body. I mean, you know, the same way we think about our heart, you know, we want our heart to last a lifetime. We don't really mind what it does for the next 24 hours. You know, we, we need to be thinking about our gut microbes the same way.

Yes, it's such a good point. And I think that for people who are having symptoms where they remove foods, because we will recommend, you know, when working with my team of functional dietitians, short-term elimination diets to help to just like turn things down and give, give the immune system a break, help with resetting. And I know you're not the biggest fan of supplements, but in these instances especially, we find supplements to be very beneficial for people to help with, like, serving as a catalyst when done in the right way, combines with a person's test results to be able to give them more relief and then improve their, their long-term ability to reintroduce these foods without having symptoms being the ultimate goal. Because, you know, you see the research even on low FODMAP diets and how for as much as low FODMAP diets have been shown to be efficacious in improving IBS symptoms, if you're on a low FODMAP diet for more than 6+ weeks, you're directly decreasing that abundance and diversity of these strains that you're talking about that can really lead a person down a bad path if it's something that you're following for years and years. Or we'll see even people that come in after working with naturopathic doctors or other practitioners who have done like food sensitivity testing on people. And so they're still removing from their diet these foods that were shown 4 years ago to create food sensitivities for them, with no one ever telling them that the goal was to reintroduce these foods in order to help with, you know, creating a level of stimulation to the immune system to teach it how to be more resilient when— train it in a way to be more resilient in exposure to these kinds of foods. Is that how you think of it?

Yeah, I think that's right. I think people often come to nutritionists with short-term problems and we need to spend much more time saying, well, I can resolve your short-term problem, but it's the long-term one we're gonna have to mainly deal with here. And that's why we can't just offer a quick fix. And you go away. It's a bit like, you know, my problems with keto diets and things like this is it's seen as a quick fix. But, you know, yes, a lot of people, if you can bear it, you might feel better on it. But long-term, it's a disaster unless you can reintroduce plants into your gut. So yeah, much more of a discussion on what are we trying to achieve here long-term for the gut? How do we get over this short-term crisis? You've got inflammation, it could be for a number of reasons. We're surrounded by a terrible food environment, processing, additives, pesticides, all kinds of things that could be impacting rather than it may not be that peanut, it may not be just the gluten in the bread. There's everything hitting us. So, we've gotta start somewhere. But if people understand the goal and they can really visualize what the gut is trying to do and the microbes are trying to do, I think it should make it easier for people on these journeys. You know, they're not blindly just saying, oh, this is good, this is bad. They can see progress. And I think it's true, you know, we had a lot of in our studies, people with IBS, Saying, well, you know, I can't take fermented foods, for example, saying, well, you know, I've been told I shouldn't have them. I get bloating. When we did the trial and we did this, you know, in about 6,500 people, so big numbers, 3 times as many people said they got less bloating after taking fermented foods than so they got more bloating. So yes, there were some people that did get it, but overall you might be improving. And I think a lot of this is, you know, that prior someone's seeded that psychological, um, seed that, you know, these foods will always make me worse. Adding new foods will make things worse. The only way is to to exclude it and then you're better. It's quite hard to change that mentality, but hopefully the science can do that and give people a much more positive attitude to trying stuff, even if it's in very small amounts and very slowly to get around it. 'Cause yeah, exclusion diets, as you know, are a great short-term but really bad long-term.

Yes, yes, yes, exactly. You recently published groundbreaking research in Nature where you assessed 100 of the most important microbes, and then you studied how diet changes those microbes. What were your findings from that study?

Well, there were a number of key findings. The first was how quickly the science changes. So in the space of 2 years, I think we doubled the number of microbes we could detect with sequencing. And so we think we can now detect over 75% of the microbes in our gut, which is kind of cool.

From stool testing.

Stool, yeah, from the stool. And using genetic sequencing methods. The other was that we found these 100 microbes, 50 good and 50 bad. That everybody had, whether they were in the UK, the US. We also found it in other European cities, in Kazakhstan, some Asian countries. So that although we're all different, we do have certain key health microbes that are useful health markers. And all these 100 were linked across these countries and peoples and ages and sexes to link with both good or bad food and good or bad health outcomes. And we'd done this study about 5 years before. And what was interesting is none of our top ones 5 years before came up as top ones now. The science had moved on and so we'd found even more powerful markers of good health. And the bad bugs, some of them were, many of them were the same as we found 5 years before. These are the pro-inflammatory microbes that are associated with eating processed foods, et cetera. But the good ones were all novel and most of them had never been described or didn't even have a name. So just a number. And they obviously really powerful, but it just shows you how science and medicine is focused on the bad guys and not really on the good guys that are helping us produce all these healthy chemicals and keeping our immune systems in really good shape. So that for us was great and it allowed us to have this new way of looking at gut health. Which is the ratio of good to bad microbes. Because up to now we've only had a method called diversity or richness where you count the number of different species and you can say how many roughly, you know, the difference between you and I is just, well, how many different species do we have? Very crude and it doesn't work very well over time. So If we both went on a really good diet, we might not see an improvement in that because my bad ones might go up as much as my good, you know, the good and the bad aren't differentiated. So that was really good. So we've got this new test that works really well around the world that means that we can start testing things like probiotics and prebiotics and, diets and people can check their gut microbes every year and see exactly what's going on, like a blood pressure. And it's just so much better than anything we've done before. So I think it's going to make a huge difference to the whole field.

Can you foresee this being like a regular thing that people are getting at? They're submitting a stool test to their doctor every year and then they're analyzing the microbes and making recommendations in maybe 10 years from now?

Yes. I mean, I think, you know, at Zoe, that's what we want people to do anyway. And you track this like you would, you have an annual checkup and you might check your cholesterol or your blood pressure. So you wanna see that your ratio of good to bad bugs is continuing to be, you know, above average and, as you're getting older, when there's more pressure on it to go down, you can maintain it. I think that is a really good holistic view of your health. And you know, as well as being a predictor of your health, it's also a reflection of your health. It works both ways as well. So I can tell much more from someone's gut microbiome about their health than say they're doing a full genetic screen. It's much more useful to you and it is dynamic. And you know, and you, we see the effects when people take antibiotics or something else, you can get a real dip. And so it's nice to be able to see how you can build that back over time. So yeah, I see this as, as it gets cheaper, it will become very routine and it's just because there isn't really a, specialty behind it in the US to support it. It's such a new science. There's no, you know, the gastroenterologists are not really interested in it. The nutrition aren't really trained in it. The microbiologist's not interested. There's nobody owning it to say this is great. Whereas, you know, if it was a cardiology test, you know, we'd all be doing it by now.

Yeah, it's so true. This is where I'd also say that functional medicine has been very ahead of the curve in assessing stool samples in patients even prior to there being enough research to say for sure that this strain is more harmful or could lead to downstream effects. You know, the concept— we just had an episode go live with Dr. Jeffrey Bland, the founder of functional medicine, and how much, you know, him just studying in the 1980s the connection between the gut microbiome and people's health. And now in my experience of being at the Cleveland Clinic and Dr. Bland's coming and training us. And I worked as Dr. Hyman's dietitian for many years that all of these concepts that were, we were seeing day in and day out in people in front of us that you have validated in the scientific work that you've done, which is bringing it to the masses. And hopefully there will be more practitioners in the United States that are able to own it because the field is— I mean, it's such an important way for people to better understand their health outside of these traditional, more reactive parameters that we're using today. And thinking about the zooming out and understanding health from a more holistic picture, I want to talk about continuous glucose monitors because this has also been used in ZOE research. I was actually part of one of the first ZOE studies where I submitted my continuous glucose monitor data and my stool test after eating the muffins that were sent. And I've worked with a number of clients. I used to actually partner with Levels and interpreted a lot of the clients at Levels, their continuous glucose monitor results. So I've seen thousands of data points. And in instances where people start using continuous glucose monitors for assessing their blood sugar, which I think can be very valuable insights, for people to better connect what they're putting into their body and how they feel and markers that are associated with it. But there also can be this point that creates like an information that isn't valuable. And instances where I see people have an increase in their blood sugar by 10 points because they ate black beans or bell peppers or something where then they're like, oh, this might— I don't want to eat this because I don't want to spike my blood sugar. And when I heard you at Eudaimonia say that now you can predict with 85% accuracy a person's glucose response based on a stool test, I was so intrigued because your work has helped me better understand the role that the gut microbiome plays on improving overall metabolic health and how we have— we can't think so short-sighted. So I'm interested in what your takeaways are for people that are trying to think more holistically. How does the— how does the gut impact this and how can we think differently about glucose spikes in a way that's productive and beneficial for our long-term health?

Right. Well, there's a lot to pack in there.

So, yeah, that was, that ended up being longer than I had.

Yeah. I was a big fan of glucose monitors when they first came out. I loved wearing the first couple, I learned a lot about food and my reaction to it, especially when you might do it with someone, other family member, and they get a very different result to eating a croissant or a bagel or something like this. Just seeing what happens when you drink orange juice, 8 years ago was a real insight. I think keeping doing it beyond the first couple of times, you learn less and less and you do see these fluctuations and the error and it's not, you know, they're not perfect every time. So you can get a bit obsessed with the small detail. Whereas in fact what we learned, we did this in 300,000 people now, is that you can broadly categorize people into the amount of sugar spikes they get and whether they get a sugar dip after it. And once you've done that, you can pretty much predict how they're going to respond to most foods without the need for a further glucose monitor. And just really understanding that yes, I'm, I'm generally sensitive to carbs or I'm more sensitive to fats as we also did looked at blood fat levels, I think is important. And I think the differences between subtleties of food was exaggerated by the very first studies. You know, people used to say, oh, you know, I respond to a banana worse than I do to a cookie. We actually found that wasn't true. Once you sort of break down the food into the amount of sugar and the structure of it, you responded exactly as you would predicted. It wasn't, weren't these huge differences between the foods if they had the, you know, the same amount of sugar. So what I'm getting at is that, yeah, it was really, useful for people to learn this about themselves. We then told them, you know, you are, you are sensitive or you're not sensitive to sugar and gave them predictive results in, in the Zoe app. But we've now replaced that with a simple questionnaire and the blood, a gut test that tells you it was 80% accuracy whether you like to have had a sugar, you're a sugar spiker regularly or not. It also tells you whether you're pre-diabetes or frank diabetes or you're on metformin. We can do that as well from your gut samples. So what we've found is we don't really need to do a CGM anymore. You know, I think it's educational, but it doesn't actually add much to our analysis, and a lot of people were put off by the blood and the technical aspect of those tools. So if we're trying to reach millions of people with our education advice, better off doing without it. Most people would prefer to do a stool sample than, you know, have to regularly stab themselves with these CGMs and play with that technology. So I think it's a real advance that we can do this. And we still don't totally understand how the microbes are doing this. We've just picked clusters of microbes that go with people that have these sugar spikes or the pre or the early diabetes. How they work, we're still speculating. We think there's probably microbes inside your gut might be sensitive and send signals within the gut, whether it's the immune system or the nervous system to increase absorption of the sugar or other mechanisms. We still don't know, but we do know from our analysis that they are associated, that your microbiome is partly responsible for how you respond to sugar. Genes play a small part, but microbes seem to be equally important. And then a number of other factors, some random, some not, are also there. It is quite complicated, but for practical purposes, we can now predict it. And that means, you know, you can select diets that are less likely to give you sugar spikes, which means less inflammation. Means less hunger. And I think we've moved on from CGMs. That's what it sort of means to me.

Yeah. I mean, I think like you said that they can still be helpful for people to understand. Like, I mean, we still have so many clients who when they put a CGM on, not only does it help with increasing their accountability if they need more of that reinforcement in the beginning, but also better understanding their body and why they feel so tired 2 hours after a meal or 3 hours after a meal. And obviously your research has validated not only that the blood sugar increase in that first 1 to 2 hours, first 1 hour in particular, is impacting their fatigue or their moodiness, but it's actually the dip that's happening afterwards that you've identified where big dippers have more symptoms than little dippers. But I think—

Yeah, educationally, I think it's great. And as you said, you can take a skeptical patient, put them through this, they can see in real time what's happening inside them. Yeah, I think, you know, as a one-off test, I think they're great. But, you know, to me, it's sort of the value wore off the more you did it. So I couldn't see. And when we did ask people whether they wanted to be retested, you know, it was diminishing number of people thought they got value from it. From the third or fourth time, for example. Most of the insights are in that first episode, which I think is really important.

But luckily I would add for women who are going through different phases, for me it's been very helpful to have my baseline data prior to being pregnant and then using a continuous glucose monitor like twice throughout my pregnancies to better understand where I was at in different stages of my pregnancy. Knowing that that impacts not only the, the mom's health, but also the baby's health so much. And then also postpartum and what we've seen and, and what your research shows is the changes in insulin resistance that happen to women as they're going from perimenopause to menopause. So I think for women that there may be additional benefits in being able to track blood sugar throughout different cycles to be able to then adjust. Since what we find is that as women age, their, their dietary needs change. In order to keep their inflammation levels lower and their blood sugar levels lower, given what you've shown in your menopausal research that those changes to the gut microbiome impact insulin resistance over time?

Absolutely. So for the keen person who likes self-experimentation, I think they're really good. I think the caveat is if you're anxious, they can make you more anxious.

Of course.

And I don't think we should be recommending for everybody. And they're not 100% accurate. They sometimes go low, give you readings and it goes in the red low zone and some people get very stressed out by this. Sometimes your morning level will shift around a bit. So it takes a fair bit of education to better use them. Safely and without stress. But yeah, generally in favor, but I don't think majority of the people necessarily need them. But I think there definitely are cases that really benefit.

Yes, I'm completely on the same page. They can create a level of obsession and in a way that then decreases the variety of the foods in a person's diet, right? And being able to understand how the variety of the polyphenols and fibers help with actually improving your long-term metabolic health instead of focusing and having such a short-sightedness around not having a 30-point glucose spike from black beans. When you think about how the black beans are changing your gut microbiome in a way that helps to support long-term metabolic health, um, I definitely think can be helpful. And it's so fascinating that you're able to predict that a person has prediabetes from a stool test. I think also demonstrating the integration between the gut microbiome in a person's metabolic health, which is fascinating. Professor Tim Spector, thank you so much for all of the work that you have done in this field. You are making such a huge impact on so many people's lives and the field of nutrition and medicine as we know it today, and hopefully a lot of changes that are to come in the next 10 years to help to be more proactive with preventing chronic disease that is largely preventable. So I just wanted to make sure to take a moment to thank you for your work and to give you an opportunity to share where people can benefit from your expertise and everything that you're working on.

So I've got my Instagram account. So if people with short attention spans, they can, if they can for like the 90-second clips that they can look at me there. I have a Substack. Where you get 5 minutes of me talking for people with slightly more attention. We have the Zoe Nutrition Podcast, which I appear on quite a lot, which is a, you know, a big scientist nutrition-led one by Zoe. Then there's a various Zoe products. Go to zoe.com. Z-O-E.com. And now you can buy the Daily 30 prebiotic supplement on subscription. You can also sign up. We're gonna have a gut test relaunch in the US in a few months. Don't show exactly when, but you can find out on that site. Lots of information on that website about menopause and things that you were talking about, the MenoScale and things like this. And there's also a free app you can download now in the US, which it allows you to look for how much processing is in food. And when you're in the stores, you can browse for that. It's also got all kinds of features, AI scanning of your food. So you can do plant counts on it. So you can actually just check how many plants are you actually eating as a baseline. That'd be a fun thing for everyone to do. And you can get that from your app or your Google Store. And yeah, and if they want to go in, they've got a lot more time, then read some of my books on this subject. We've got, there's a Food for Life cookbook which is out in the US, which has a little introduction to the gut microbiome and then how you can apply some of those principles of feeding for your gut through 100 recipes. I think they're the main ones. There's plenty more and we're trying to continually update things as the science changes.

Yeah, it's amazing that you do as much as you do and are putting out as much into the world. I will also plug Spoonfed, which was a book that I read many years ago. I think it was 2020 that I read Spoonfed that validated so much that I would highly recommend if you're looking for a good book to read.

Yeah, and this Ferment is another one that came out on fermented foods, came out in Europe anyway, which you can probably get hold of a copy if you're into how to fermenting foods and the latest science about them.

Oh, okay. I'm gonna have to pick that one up. And you have a new book coming out soon, is that right? Or you're working on?

I've always got a new book coming out. Yes, there's another one. So we've got a, our second cookbook, which is about improving brain health. So the gut-brain connection, that's the next one.

Amazing. Well, again, thank you for all of the work that you do, and thank you for being here on the Being Brigid Show. I will see you next time.