ZOE Science & Nutrition - Inflammation, aging and disease. What's food got to do with it?

Episode Date: June 9, 2022

It’s a biological process that we need to stay alive. Yet too much of it leads to disease and a shorter life.  Inflammation is the immune system’s response to an outside event it thinks is dangerous. This stimulus could be an injury, like falling off your bike or an infection by a virus or bacteria. But inflammation can also be triggered by our food in the hours after we eat.  But if this natural process is required to protect us from infections and injuries, why is inflammation usually cast in a negative light? Is there something behind this, or is the idea that inflammation is bad a lie, designed to sell magic potions with dubious evidence?  In today’s episode, Jonathan speaks to two show regulars to unravel all the information about inflammation: Dr. Sarah Berry is one of the world's leading experts on human nutrition, who has personally run over 20 randomized clinical trials looking at how humans respond to different fats. Tim Spector is a co-founder at ZOE and one of the top 100 most cited scientists in the world. Download our FREE guide — Top 10 Tips to Live Healthier: https://zoe.com/freeguide Timecodes: 00:00 - Intro 00:09 - Topic Introduction 02:30 - Quickfire questions 04:27 - What is inflammation, why does it happen, and why it’s not always bad 10:38 - How is diet related to inflammation? 14:15 - Microbiome and inflammation 19:31 - What does prolonged inflammation do to your health? 23:06 - Can inflammation affect our weight? 25:24 - How does inflammation affect aging and menopause? 29:21 - How do we reduce our dietary inflammation? 33:26 - Should we exclude foods to reduce inflammation? 37:06 - Summary 38:49 - Goodbyes 38:52 - Outro Episode transcripts are available here. Follow Sarah: https://twitter.com/saraheeberry Follow Tim: https://twitter.com/timspector Follow ZOE on Instagram: https://www.instagram.com/zoe/ This podcast was produced by Fascinate Productions

Welcome to ZOE Science and Nutrition, where world-leading scientists explain how their research can improve your health. Today we discuss a biological process that we need to stay alive, yet too much of it leads to disease and a shorter life. Most of us have heard of it, but don't really understand what it is. When linked to food, you almost certainly have an opinion. Many of you, like me, will have assumed any relationship was quack science. It turns out we were wrong.

The process I'm describing is inflammation, which put simply is the immune system's response to an outside event it thinks is dangerous. This stimulus could be an injury, like falling off your bike, or an infection by a virus or bacteria. But inflammation can also be triggered by our food in the hours after we eat. In all these cases, the immune system activates processes designed to heal the body. But if this natural process is required to protect us from infections and injuries, why is inflammation usually cast in a negative light? Is there something behind this?

Or is the idea that inflammation is bad simply a lie, designed to sell magic potions with dubious evidence? As it turns out, if inflammation continues for long periods, it can have a severe negative impact on our health. Long-term inflammation is now linked to many major diseases, from dementia to heart disease. Recent research has shown that what we eat can be an important cause of long-term inflammation. This dietary inflammation can be caused by repeated shocks from the food we eat, month after month, year after year. This long-term inflammation has severe implications

for our health, increasing the risk of serious disease and potentially weight gain and accelerated aging. On today's show, we find out how we can reduce dietary inflammation, which foods can help, and discover how our gut microbiome could play an important role. dietary inflammation, which foods can help, and discover how our gut microbiome could play an important role.

I'm joined once again by two of our regulars, Tim Spector, one of the world's top 100 most cited scientists, and Sarah Berry, one of the world's leading experts in human nutrition. Sarah has carried out more than 20 human clinical trials investigating the inflammatory processes triggered by different types of food. Sarah and Tim, thank you for joining me today. As regular listeners will know, we like to start with a quick fire round of questions from our listeners before then going into more detail. So I have three questions here for Tim and then three for Sarah. So Tim, is all inflammation bad for you? Short answer is no. We need inflammation to stay alive because it protects us against injuries, cuts, infections, and foreign bodies fighting them off. So when it goes wrong, it's bad, but generally we need it. It's part of our defences. Which I think will surprise a lot of people. Second one, is inflammation from food a real thing? Short answer is yes and the reasons

are actually quite complicated and it's not just all about allergy. Can inflammation cause ageing? It can certainly be a major factor in ageing and getting the balance right of our immune system is found to be crucial in how we age. Amazing. Sarah, is there a link between processed foods and inflammation? Yeah, there is. Sarah's going to go short and sweet today, I can see. Can eating too much fat cause inflammation? Depends on the type of fat, but more importantly, the meal that it's consumed in. Are there specific inflammatory foods you should exclude from your diet? I'm not going to demonize any single food. Yes, there are some foods that we know are more pro-inflammatory, but it's really dependent on the overall dietary

pattern. Brilliant. And I think we'll dig into all of that now over the rest of the podcast. So as we kick off, I have to admit that five years ago, I thought inflammation related to food was some sort of pseudoscience thing, you know, an excuse for crazy diets and weird detoxes. And so I'm sure for a lot of our listeners, it's very surprising to hear that this inflammation thing is real and that it's important. And so Tim, maybe can you help us just to understand a bit more what inflammation is, why it happens, and I think probably surprise many of us by saying it's not always a bad thing. Yes.

So we've evolved to have this process of inflammation, which is the body's natural response to any threat or injury. So when you knock your hand and maybe get a small cut on your arm, it's bruising and that signals the body to send out chemicals to basically repair that area. So you get an instant response of some blood going there to stop the bleeding. If there's a bit of foreign bodies in there, you get some white cells which come to actually attack the invaders. And at the same time, you get changes in the blood vessels which open them up, make more blood flow in that area so that it can help get defense chemicals there and take away any rubbish and damage. So all that is what is going on inside when on the outside you're seeing redness, pain, swelling, etc., which is what we call inflammation. And in a way,

it's going on all around our body all the time as a natural defense mechanism. And we're learning more and more that this basic mechanism goes on to prevent all kinds of diseases and all our cell processes. And to a lesser extent, it's also helping us just mop up all the chemicals that get produced as a side effect of day-to-day life. Just like in a factory, you get these electric sparks in machine works. Our body produces these free radicals, and then you have our body coming and mopping up those and taking them away so that we can continue our normal function. That's really important to realize that inflammation is our friend. And like most of these processes in pathology,

it's only when it goes wrong or the fine tuning of it gets out of kilter do we end up with problems. And when you talk about it going wrong, what does that mean? And you gave this example like cutting yourself, that's very straightforward. And also this thing of byproduct from food, is it triggered in other ways? And what does it mean when you say it goes wrong? Well, it can go wrong for a number of reasons.

So you might have developed some disease like an autoimmune disease where you're getting an unnatural response to your own body. And that also happens in food allergies. So it thinks it's a threat. It's not really a threat, but it's like it is. And so it continues and it can't get rid of it like it would do. And therefore you get this chronic inflammation. You might have some infections like tuberculosis that are hard to get rid of. And you can end up with this longstanding inflammation that you can't shift. And increasingly, we're finding out that lots of chronic diseases get to a certain state that

if the body can't correct the metabolic problem, you continue with this low-grade inflammation that's sort of just trying to deal as if it's an acute injury doesn't quite work. So you get this low-grade inflammation and so that's diseases and that's also happens with aging as your body is less able to really fine-tune this narrow line between fighting off infection and the immune system and we also know that food affects it so that if you are regularly eating the wrong kinds of food you can also develop short-term peaks of inflammation that leads to a long-term inflammatory pattern just because your body's not quite responding well it's just overreacting to some of these

things that perhaps when you were young and healthy you wouldn't have reacted to. Yeah I think as well modern life is not the friend of inflammation as well, because we know that so many of the lifestyle and dietary factors that now change in how we live our life impact inflammation. And I think this is something often people don't think about. So we know that sleep deprivation stimulates chronic inflammation. And we know that from sleep studies where people ask to limit their sleep and then you can look at inflammatory measures. We know stress directly causes inflammation. We know that diet, like Tim said, causes inflammation as well. And we know

that having a moderate level of activity, so moderate level of exercise can actually have anti-inflammatory properties. And so the way that we live our lives in a sedentary often sleep deprived stress state is really not helping matters and it also within our current food environment as well. So those of us with small children working from home may not be in the optimal situation to manage their inflammation is that what you're saying Sarah? Yeah it means you and I are stuffed Jonathan. Just before we go on just a big difference to say that there's a difference between acute inflammation which is what happens when you get a an infection or you know you get Covid or whatever it is and chronic inflammation which lasts months or years and I think that's

an important distinction because acute inflammation is fine and not a problem. But if you have repeated acute inflammations, that leads often to this long-term or what we call chronic state of inflammation. And that's really what we're trying to avoid here. We now know that actually most chronic diseases are underpinned by inflammation, that we know that whether it's heart disease, type 2 diabetes, you know, some mental health disorders have been linked to inflammation, also dementia, Alzheimer's, some cancers as well. So we know that if we can start to tackle some of these chronic inflammation that Tim talked about, we might be able to somewhat

attenuate our risk of some of these more chronic inflammatory driven diseases. And so how does food fit into this? And Sarah, I know this is one of your big areas of research, right, is how does food affect our body in the hours after we eat? Is there such a thing as sort of dietary inflammation? And if so, can you help us to understand how that fits into this picture Tim has drawn between sort of short-term inflammation, good, keeps us alive. So we like that long-term inflammation, I think you're saying tying into all of these really bad impact on our health. Yes, there's two different ways I think we can think about how diet impacts inflammation. One is how food is actually metabolized, and I'll pick up on this in a minute, but also how the food itself might directly impact our inflammatory response.

So there's two different ways that food can impact these inflammatory pathways. But the good news is that it kind of gives us two bites of the cherry, that there's two different kind of strategies we can take with our diet in order to minimize inflammatory responses from food or other external stimuli. So when we consume foods, we consume foods that contain mixed nutrients. So they typically contain fat, carbohydrate, protein, and fiber. What we know is that when we consume any fat in the food, you have an increase in circulating blood fat, and you have an increase from the carbohydrate in the meal in circulating blood sugar. This happens really quickly. So your blood sugar can peak within about 30 minutes in the blood and your blood fat can peak within about four hours in the blood. But what's important is this initiates a kind of cascade of events.

And a good way of thinking of it is it's setting off like these mini fires of inflammation in your blood that affect the lining of your blood vessels and have other downstream unfavorable effects. So given that most of us don't just consume one meal a day, given that we consume multiple meals, and given that many of us also consume quite highly processed food that's really rapidly digested, this means that throughout the day, you've got all of these fires burning throughout your body stimulated by this increase in blood sugar and blood fat. And over day after day repeated, and if you don't have suitable defences in place from other properties of the food, then you're in this chronic state of inflammation. The good news is, though, that you can partly reduce your excursions,

these peaks in blood fat and these peaks in blood glucose, but also there's components in food that can kind of dampen or put out the fire, so act a bit like a firefighter. And a really good example of this is polyphenols. So polyphenols are found in extra virgin olive oil and lots of highly pigmented fruits and vegetables. And I think a nice way to illustrate this is a study that was done some years ago where they fed people a really high fat meal consisting of refined olive oil, which means basically it's just like consuming a typical vegetable oil that you'd get in a

supermarket. So it has none of these like wonderful bioactives of polyphenols. And then they fed people a really high fat meal consisting of extra virgin olive oil. When they fed the people the meal that contained the refined olive oil, you had a really big increase in circulating blood fats, you had a really big increase in inflammation and oxidative stress. When they fed the people the extra virgin olive oil, you had the same level of increase in blood fat, you still had this increase in blood fat, and therefore kind of a spark of a fire going off. But actually, the polyphenols in this put down that fire and meant that there was hardly any increase in inflammation, hardly any increase in oxidative stress. And also there was almost no effect on the functioning of the blood vessels, which is the ultimate downstream kind of

harmful effect that we see in this post-meal state from this inflammation. Got it. And how does the microbiome fit into this story? Because you're talking about these protective elements. How do bacteria fit into this story of inflammation if they do at all? Yeah, the microbiome is incredibly complex at the moment. It's made up of trillions of individual microbes. We're all very individual and these are like chemical factories. So what we know is that many of the ways in which fat and sugar are broken down are in part controlled by our gut microbes. So there's, in a way, a direct effect. Particularly, we know much more about the fat pathways because we know that microbes actually produce many of the things like bile salts and other

enzymes that break down fat and allow it to get recirculated into the body, which we only thought that only occurred in the liver. We now know actually our individual gut microbes do a lot of this. So having the right set of gut microbes will help you break down fats so they don't hang around in your body after six hours and lead to this stressful inflammation. So it's true, we don't really understand how microbes currently influence blood sugar. We know they do to some extent, but we don't know where that happens, probably because it occurs in bits of the intestine that are hard to reach and hard to study like the small intestine. But the other general picture about inflammation, and it sort of says, well, can microbes control inflammation in general? The evidence is overwhelmingly yes, because

we know there are pro-inflammatory microbes, we know there are anti-inflammatory microbes, that when you do experiments between humans and rodents, you can create inflammation in some mice and then transplant their poo sample to sterile mice, and they will cause that inflammation in those animals. And sorry, Ted, you're saying you transfer, what do you transfer from the mice with inflammation to the other mouths? Well, you can transfer inflammation from one mouse to another via their microbes. So it's suggesting that the microbe is then for the

source of the inflammation and not purely a secondary event. And you do that against controls. So that's amazing. So you're basically saying the mouse is completely the same, none of the things you described before with infection or cutting the mouse or any of the rest of it, just their microbes. It's a sterile mice, for example, and you compare it with inflammatory microbes that may have come from a human and normal control microbes from a human, you put them in mice and the inflammatory one will produce a similar inflammation in the mouse. So that's why we know it's not just correlation, there is a causal element to it.

It's amazing, right? So you're basically saying these completely other organisms we don't think about as being part of us, we transfer them to somebody else, and suddenly it's affecting this very complex system you're describing around inflammation that is, you're also saying is impacting so many of our long-term health and things like this. If you'd said this 20 years ago, right, people would have said you were probably crazy. That would definitely lock me up. Yeah, that's true. They're trying to now, but I get away with it. Yeah. So we have this really good base whereby you take human samples of disease, and non-disease people,

people with particularly autoimmune disease or these chronic infections, who have longstanding inflammation and you can make sterile mice quite sick with the same ones. And so we also know that that can be partly reversed and that by putting in a whole series of anti-inflammatory microbes, you can partly reverse this process. And when you look at difference between microbiome studies of healthy versus unhealthy people with chronic inflammation, they always have a lack of these anti-inflammatory microbes, which all healthy people have, which seem to dampen down inflammation.

And generally, all these unhealthy groups, all those chronic diseases tend to have microbes that really like inflammation and rub their hands with glee when they're in a nice environment, an inflamed environment, perhaps because the acidity has slightly changed or the environment around is slightly changed, that they just love that and they do really well. And we think they produce pro-inflammatory messages, substances to keep the whole process going. So they're both a marker of inflammation, but they're also probably a driver as well. And so increasingly, we see that the microbiome is key to inflammation. And the good thing about the microbiome as opposed to our genes is that we can manipulate it through diet and through drugs and through antibiotics, probiotics, etc. And so you've painted this picture where the inflammation

could be reduced both through aspects of our food, I love this idea of them as firefighting and these microbes themselves could either be arsonists or firefighters, depending upon which we have. Sarah, could you, because I know this is something you study a lot, and could you help us to understand how you move from this sort of immediate inflammation after a meal through to eventually these impacts on your long-term health that you touched on earlier because I think it's not really clear this link between the two. So imagine you've got these constant fires going off that we talked about that yeah your body and the other food components are trying to dampen and put out but eventually you're kind of like

on this tipping scale of trying to constantly balance this out. And sometimes either the defenses in the food that we're actually eating or the defenses from our body just aren't strong enough and, you know, tips us over the balance and it puts us into this more constant pro-inflammatory state. But also as well as increasing our baseline inflammation, so our kind of fasting inflammation as we can think of it. We do know that all of these short, sharp rises in inflammation, these fires that are going off, cause immediate damage. So we know that they impact, for example, how our blood vessels function. And so we've done lots of studies at King's where we feed people different types of

fats or different types of foods. We look postprandially, so we look post-meal at their changes in the fat and in the sugar in the blood. We look at changes in inflammation and we also look at actually physical changes in how their blood vessels function. And there's particular techniques that we use using ultrasound, for example, where we can look at how healthy the blood vessels are. And we actually see just within a six-hour period of the initiation of this inflammatory response post-meal, an impairment in how your blood vessels function. And you can actually see physical changes, we know from mechanistic studies as well in the lining of the blood vessels, which is causing this deterioration. And over time, this can lead up to what we call atherosclerosis, which is a kind of furring of our arteries. That's just kind of one example of how it impacts us and therefore

affects, in this case, cardiovascular disease. You have similar kind of pathologies going on at the level of the pancreas where repeated inflammation at the pancreas, which is really important in terms of insulin resistance because it produces insulin, where it affects the functioning of the cells, our beta cells in the pancreas, and therefore also can affect the production of insulin. And that downstream affects our risk of type 2 diabetes which then triggers a whole cascade of other effects related cardiovascular disease obesity etc. I can attest to that because Sarah actually tested me after giving me massive amounts of cheddar cheese and dairy milk chocolate to eat so I did those ultrasound studies. And how did you do, Tim? Well, I had actually a very high fat response, if I remember,

but the vessel response was actually quite good. They were still quite elastic. Yeah, Tim was the epitome of a healthy 18-year-old. So although he had a reasonably high fat response, his body defences to putting out that fire were fantastic. So the ultrasonographer that did the research on him was quite shocked and we did actually go back and check his results because we couldn't believe not saying that he's much older than 18 Jonathan but so that's all of those good microbes that's

that's good to hear so so this is the best advert for eat like Tim Spector and then you'll have an 18 year old blood vessel very Very bouncy blood vessels I think that was the point but so we've got this chronic inflammation and it is linked to putting on weight we haven't really discussed that but it is linked to weight gain and we can talk in general about the whole system being stressed and the metabolism being stressed and everything's slightly under control. Do we really know why chronic inflammation is linked to weight gain in specific mechanisms? I don't think there's clear enough evidence. I think what's really clear is that increasing weight, so if we can look at the other direction first, we know that body

fat produces inflammatory compounds. So we know that if you put on weight, you increase your baseline inflammation, hence one of the mechanisms why obesity predisposes you to all of these kind of chronic inflammatory conditions like type 2 diabetes, cardiovascular disease. We know from weight loss studies, as soon as you lose weight, even if you haven't changed your diet in terms of the quality of the diet, but you've lost weight, we know that you can have a big reduction in many of the quality of the diet, but you've lost weight, we know that you can have a big reduction in many of these inflammatory compounds. How it works in the reverse, we don't understand yet, but mainly because it hasn't been looked at in a lot of detail. We do know that there is some evidence that inflammation is a precursor for weight gain.

We know that, as I said a minute ago, that it increases insulin resistance and type 2 diabetes. And we know that it also can impact how we metabolize our food. It could be acting through sugar peaks, for example, just in a very simple way, one of those methods that if you get inflammation, those sugar peaks are going to be bigger, then you start to gain weight. That could be one mechanism. Yeah, there's bi-directionality for sure we know very clearly the evidence for obesity or weight gain influencing inflammation the other direction i think it's something that we need to spend more time focusing on it had always been assumed it was one one direction but as we see with most food disease related pathways,

there's always two sides to every story. Yes. So as well as weight gain, we had a lot of questions around two other things, menopause and aging. So maybe we can sort of touch on those before talking about, okay, what I'm sure most listeners are really interested in, which is, okay, what can I do to reduce my dietary inflammation? So what's happening to inflammation during menopause? And then if we think about aging, more broadly, Tim, you touched right on the beginning that inflammation seems to be very linked to it. Can we sort of cover those two topics? Should I start with aging? So as we get older, our immune system changes, and microbiome also changes. And the two are very closely linked so that most of our immune cells are actually in the gut lining, 70% of them. And of course,

our microbiome is mainly in the lower part of the intestine, the colon. So they're interacting all the time. Our immune cells are changing with age and our microbiome starts to change really subtly, but quickly once you get into your 70s. And I think what we're looking at with aging is balancing these anti-inflammatory responses that's crucial to just getting enough so that your immune system can attack invaders, stop infections and stop cancers. So interestingly, this whole system is also related to the ability of your immune system to recognise cancers and pick them off early and not overreacting and giving you autoimmune disease and other things. And I think the ability to react as you get older starts to wane.

And that fine tuning that's going on all the time, you know, constantly your body is trying to work out, do I attack this? Do I let it go? Is this a food protein? How much invest energy in fighting whatever it is, starts to go a bit wrong. And we see this.

And once that happens, you get this imbalance and you start to get less control of inflammation for things that shouldn't normally cause it or wouldn't have caused it 20 years before. So that's why you get more inflammation with things like foods, as we've talked about, or minor traumas. And this has been linked very clearly to risk of not only cancers, heart disease, but also dementia. All of these are part of this immune regulating system that is stopping minor injuries, but also getting rid of these waste products we talked about earlier,

these free radicals, the sparks, if you like, of metabolism, they start to accumulate. This also leads to more inflammation. So it's just a great system. It just wasn't built to live for 80 years. It was, you know, you're out of warranty at that time. And that's really what seems to happen. And these things start to go wrong. And that's

really a unifying reason why our immune system and our microbiome are so crucial in the aging process. And the more we can keep our immune system along the right lines via our food and our microbiome, the more we can prevent rapid aging and all these other problems. And Jonathan, there's some lovely studies that have been published, RCTs and a high number of them that quite consistently show that if you can increase bioactives such as polyphenols in people's diet, you can somewhat reduce some of the cognitive decline. So you can improve their memory, their brain responses. And this is from supplement studies as well as whole food studies. And I think when the researchers have looked at some

of the mechanisms behind this, it quite clearly shows that there's one of the mechanisms is this inflammatory response that's reducing some of the inflammation over a period of time and therefore is attenuating it. And so hence the association as well with food and dementia because of some of these inflammatory pathways. The other side of that is there was an Irish study about 10 years ago out of Cork that looked at people going into old age people's homes. So they were independent living and generally people's microbiomes really got much less diverse three months afterwards once they started getting into institutionalized cooking and food which was less diverse and the people who had the worst microbes had much earlier

mortality and problems with heart disease and dementia. So I think, yeah, absolutely. Good food is absolutely even more crucial as you get older and your immune system starts to wobble. Yeah, and we see this with the menopause. So we see pre and post menopause a huge difference in firstly fasting, so kind of chronic inflammatory levels, as well as this post-food inflammation. So up until the age of about 40, 45, until you get to that perimenopausal, that kind of transition into the menopause stage, women are actually doing really well compared to men. So women tend to, if they're in the premenopause phase, have a lower inflammatory response compared to age-matched males. As soon as they hit that phase of transition and become post-menopausal, then their inflammatory responses kind of go

skyrocket through the roof and actually overtake males' responses. There are big effects of the immune system, really big changes in the immune system and menopause, and we see this with not only what we're talking about here, weight gain and the immune system and menopause. And we see this with not only what we're talking about here, weight gain and the immune system and microbes, but all kinds of autoimmune diseases change. So actually improve. So some things like lupus actually get less common after the menopause and others get more common. So it's a time of big change in the immune system, microbes, weight, metabolism, everything. So we've talked about a lot of things that can happen that are bad and we always like to say well you know what can you do about it

so um what can our listeners do to reduce their dietary inflammation and i had a lot of questions asking about specific foods so dairy nightsh vegetables, even tea as things that cause inflammation and should they be cut out? I also had a great question saying, are there any super hacks for inflammation? An example was like sprouting peas in the dark for histamine that we had on another podcast with Will. So other than of course doing like a full Zoe test, what should people do about this? I don't think there's any magic bullet with inflammation. And I think this is the problem where these anti-inflammatory diets have verged into this whole arena of pseudoscience because, you know, people are saying, oh, eat one goji berry a day and you'll live forever. And, you know, look 20 years younger because it's anti-inflammatory.

I think that there is robust evidence for some foods having anti-inflammatory properties. There is robust evidence that for some foods being more pro-inflammatory. But I think the kind of wealth of the evidence points to us considering our dietary patterns. So considering not just individual foods, but our overall dietary habits, as well as our overall dietary patterns. So considering not just individual foods, but our overall dietary habits, as well as our overall dietary patterns. And there's a index called the Dietary Inflammatory Index, which brings together thousands and thousands of studies, including a lot of randomized controlled clinical trials, and has come up with 45 components where there's robust evidence that they have either a pro or an anti-inflammatory effect. And these consist of particular foods. So these would be foods such

as garlic, ginger, oily fish, for example, nuts, seeds. And it also consists of nutrients where we know, for example, there's good evidence for omega-3. We can pick up on this. And Sarah, these are the good ones or the bad ones, just to understand? So these are the anti-inflammatory, such as omega-3 and omega-6. And omega-6 might surprise some people, we can pick up on that, but also lots of bioactive. So lots of the kind of compounds, such as polyphenols that we've mentioned, but a lot of compounds that are in herbs and spices as well. Can I simplify that message? Because I think in the modern science, we've moved away from this reductionist idea of picking a few ingredients of these things

and saying that was in a laboratory, that's anti-inflammatory or that's pro-inflammatory. And I think what I saw in my research is that basically everything that has these phytonutrients, these polyphenols that are food for our gut microbes, and they're made of whole plants and they've got some fiber, tend to be anti-inflammatory. And stuff that is ultra-processed, that contains artificial chemicals, junk food, is processed. So it's actually much simpler than trying to work out which particular ingredient because we're talking about hundreds of components in each of these.

And I think generally things that are good for your gut microbes tend to be anti-inflammatory. And things that we know are bad are bad and we're just skimming the surface of the reasons why but I think I don't want people to go away the idea they've got to look up a whole list of foods to say this is good or bad when I was treating patients with rheumatoid arthritis and I was a rheumatologist used to have many patients would never eat tomatoes because they were told that these are particularly bad for inflammation. And there is actually no evidence for that at all. And if you eat a diverse range of plants, particularly vegetables, that's going to be an anti-inflammatory diet per se. I don't think you have to

look at it in any great detail. And all these other stories, as you mentioned, are probably false now. They're done on very small numbers or outdated methods and techniques. So I think we need to be much broader, holistic in the advice we're trying to give people. And what about excluding things, Sarah? So I think we had a lot of questions around this and Tim gave an example, right, with tomatoes and saying, well, I'm worried about inflammation. So I'm worried about there being various foods which are inflammatory. And I think here we're talking about whole foods. We're not talking about the ultra processed foods that you were talking about. Are there a set of foods that people should be giving up in order to reduce their inflammation? So I don't think that

anyone should ever give up any foods that they I don't think that anyone should ever give up any foods that they enjoy. I think that they should think carefully about how they balance the foods within their diet. I think that there's good evidence around processed foods, as you've said, but in terms of individual foods being particularly harmful, I'm not aware of any that there's robust evidence around if consumed in moderation as part of a healthy diet. I mean, you know, excess alcohol. Yes, we know that in excess, that's particularly bad for inflammation. But Tim, unless you know of a particular. There's some evidence about nitrite containing foods, which are, you know, but often they're usually processed.

But it's quite complicated because nitrates are actually anti-inflammatory and nitrites are potentially pro-inflammatory. I can see that could get me in trouble. There's subtle distinctions that mean everything. It's very complicated and it's not all the same. And so there's been a lot of misunderstanding that anything with an n word in it is seen as you know deadly and you have to avoid it and most a lot of plants and vegetables contain lots of good nitrates they get converted by

microbes and nitrites in different amounts of people but i think we shouldn't have foods to avoid because we shouldn't be eating that much of that food anyway. And if you did eat it, it's one of those 30 plants you should be having a week. So even if it was not at least neutral or slightly bad for you, it would be overwhelmed by all the other foods, as long as you've got that diversity on your plate. And I think that's probably the big message. And we're going to know much more about these foods in the next 10, 20 years than we do now. We have very primitive knowledge.

So I think we've come a long way in the last few years, but we still don't understand, you know, the 600 chemicals that are in the average plant and what they do to our bodies. But generally, you know, we know they're good and that's what we should be supporting. And I think going back to a point I made earlier, plants are designed to protect themselves, not just us. So if we think of vegetable oils as an example, the more polyunsaturated fatty acids there are in a vegetable oil, which we know are more prone to oxidation, which therefore might increase inflammation in our bodies,

but oxidation within the plant, the more polyunsaturated fatty acids there are, the more antioxidant compounds there are in the oil. And so if you have a very polyunsaturated fat rich oil that has more vitamin E often or more polyphenols, yet when you have an oil that's very rich in monounsaturated fatty acids, which is less prone to oxidation. It has a lot less of these antioxidant compounds. So the plants themselves inherently actually have their own defence mechanism to look after this oxidation, which when we consume is what causes some of this inflammation in us. Which is the sponge, just as a simple term. This is these chemicals which

sort of sponge up the damage due to our everyday metabolism. And that's what we call an antioxidant, which I think is a bit of an outdated term, but we haven't found a better one. Brilliant. Well, I think we are sadly at time, and I have so many more questions as always. I think if we sort of look back over the podcast, I think we started by saying that inflammation is normal, and that's really important. And that actually to have short bursts of inflammation is indeed good and required to keep us alive. So it's a sort of this prolonged long-term inflammation is bad. And it's a problem that you then said is linked to long-term diseases, linked to weight

gain, then said that dietary inflammation is real, so the food we eat actually really can affect our inflammation, that the microbiome seems to play a very important role in this, that menopause is a period where we see huge changes in inflammatory levels sort of before, during, and afterwards, and the microbiome is also changing there as well. And then as we think about aging in general, the immune system is very involved, it's degrading. And then the end, I think we said sort of what can you do? And Sarah, I think you said there's no magic pill. So there's no, unfortunately, superfood that we can just eat to solve all of this. But that in general, I think, talked a lot about polyphenols, which are all these

different chemicals in plants, that there's some evidence that this can actually improve brain function as we're thinking about aging, that in general, ultra processed foods tend to be bad for inflammation. But then when we're thinking about other foods, critically, don't think about cutting foods out. There's not a whole set of sort of inflammatory foods, normal foods that you should cut out. So it's more about whole set of sort of inflammatory foods, normal foods that you should cut out. So it's more about, I think Tim was pushing hard, you know, a diverse diet. And Sarah, I think you taught, I caught fruit, vegetables, oily fish, you know, nuts are things that in this sort of anti-inflammatory diet come out particularly strong. Brilliant. Thank you both.

Thank you. Thank you. Thank you to Sarah and Tim for joining me on Zoe's Science and Nutrition today. We hope you enjoyed today's episode. If you did, please be sure to subscribe and leave us a review as we love reading your feedback. If this episode left you with any questions, please send them in on Instagram or Facebook and we will try to answer them in a future episode. At Zoe, we want to improve the health of millions of people around the world by starting with an at-home test and then using the latest science to identify the right foods for your body. If you're interested in learning more about Zoe, you can head to joinzoe.com slash podcast and get 10% off your personalized nutrition program.

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