How 'boosting' your immune system increases inflammation and 4 ways to support balance instead with Dr. Giulia Enders

What if boosting your immune system is the wrong goal? 

Today, Dr Giulia Enders explains how boosting immunity may increase inflammation and why your symptoms are often part of your body’s defence. Your immune system is not failing when you feel sick. It is trying to protect you. So what should you focus on instead?

That’s the idea at the very heart of Giulia’s new book, Organ Speak. Giulia is a gastroenterologist and author whose previous book, Gut, sold eight million copies and helped convince the world that gut health was worth taking seriously.

She explains how the immune system really works and why symptoms like a runny nose, cough, or fever come from your body, not the infection itself. You’ll learn how sugar may push the immune system toward inflammation, how stress can weaken it, and why sleep is key for producing immune cells. This episode also explores how exercise helps regulate your immune response. The core idea is simple: health is not about making your immune system stronger. It is about keeping it balanced.

If the sneezing, runny nose, fever - all of it - are actually the whole point, how much energy should you spend in suppressing them?

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Actionable Takeaways

Should you "boost" your immune system?

Not exactly, a steady, well-regulated immune system is the goal. Your long-term daily habits, like sleep, diet, movement, and stress management, shape how well your immune system responds when needed before settling back down.

What do cold symptoms actually mean?

They are signs your immune system is doing its job and clearing the infection, not that your body is “failing”.

Should you treat symptoms or let them run their course?

It depends. A decongestant can help you sleep, but it’s worth being cautious about stopping symptoms that may help clear an infection (like diarrhea), unless it’s severe or you’re becoming dehydrated.

Why is sleep before midnight so important for immune health?

The first half of the night tends to contain more deep sleep, which is when your immune cells are produced, and overnight repair takes place.

Can exercise help your body recover from stress more efficiently?

Yes, regular exercise, especially a mix of strength and aerobic training, supports immune readiness and stress recovery.

Can short breathing breaks reduce stress and support immune balance?

Yes. Just 60 seconds of slow breathing once or twice a day can reduce stress hormones and support a more balanced immune response.

Transcript

Jonathan: Is boosting your immune system a good idea?

Giulia: Not necessarily, no.

Jonathan: Does a runny nose help you recover from a cold?

Giulia: In a way, yes, it does.

Jonathan: Can poor sleep harm your immune health?

Giulia: Yes, definitely.

Jonathan: And finally, what's one fact about the immune system that just blows your mind?

Giulia: That it is actually comparable to consciousness and far more connected than AI networks are.

It is, in a way, cellular intelligence at work and at its best.

Jonathan: Whenever I get a cough or a cold, I immediately feel like my body's letting me down. Like it's a failure, I'm failing, and like my immune system is not doing what it should.

And I was really struck that in your new book, you're sort of completely reversing that way of thinking. You wrote a previous book that was called Gut that was a huge hit. There were about, I think, eight million copies sold. But particularly for me, I actually read that book at just the time that I met my co-founder, Tim Spector, and at that point I knew nothing about the microbiome, I knew very little about the gut, and your book helped convince me basically that Tim was not mad - that gut health was really important, the microbiome was really important, and so this thing was really credible. What first drew you to this topic of gut health?

Giulia: It was at first a very personal experience. I had a skin disease, and the doctor would prescribe me, you know, corticosteroid creams, and it would make it better for a little bit, but then it'd just come back.

And I thought to myself, "Well, I'm in this body for, I think, another like 70, 80 years maybe, and I know nothing about it, and this is a bit odd, isn't it? I should know more." So I started reading and trying to find ways to, you know, get my skin healed back up again. And then during that time I read about the gut and I was completely blown away.

It's so intelligent, it's so versatile, and it mediates so many important processes. So then I studied medicine, and every time the gut came up I was there. You know? I really listened. And then I thought, "More people should know all these things. They're so helpful and also interesting and sometimes funny.

And well, then that really tipped it off.

Jonathan: And so clearly, you know, that took you all the way through. You became a doctor, you became a gastroenterologist. But in your latest book, Organ Speak, you've sort of expanded to other parts of the body. So you've sort of cheated on the gut a little bit here. What's inspired you to do that?

Giulia: It was the work in the hospital. After I finished my studies, I went to work in a hospital specialized on gut disorders, and after a while I just had to come clear and face reality, which, you know, meets you there in the hospital, which was, I'm not a good doctor if I only focus on the gut. I'm missing out on all these connections, on all these other things that influence the gut.

I realized after a while that there was a group of my patients with irritable bowel syndrome where they would sleep poorly, and I would repeatedly hear this when I was questioning them in the beginning. And so I got into reading about the brain and sleep, for example, and I realized, oh, there is a part of sleep that is really important for pain threshold and how much pain we feel.

So this could influence it, and also the gut homeostasis and how everything's repaired during the night. In the body, everything is connected. And in research we always try to, like, tidy it up and separate it all to have, like, good, nice, and clean results, but you can't do that in the hospital because, you know, there the human is built back together again so yeah.

And then there were other things like people coming in with belly aches or even appendicitis more often when the air quality was poor in the city I was working in. And we had that often because we had lots of cruise ships coming in. It was Hamburg. So, you know, I started reading about the lung and air quality, and this is sort of, like, how it took off and things kept piling up and made me want to say something again, like that felt with the first book.

Jonathan: So how has that experience changed the way that you think about, I guess, health and disease?

Giulia: The way I see the body now, I think is a bit more sophisticated. Suddenly I started to have this respect for other things. Why are they put in this place? What are they especially good at, and how can I actually make use of that in my day-to-day life and really have, like, a more cooperative and appreciative relationship to these organs?

And this has made me, I think, more appreciative, but has also, like, drastically changed what I think I am and what others are. I think it's also important to just see this miraculous, crazy thing of being alive sometimes. Just let it shine through a little bit. That has done that to me.

Jonathan: I love just hearing the enthusiasm, but also you don't sound like a typical doctor.

Like, I feel like a typical doctor does, like, carve this up into pieces- ... try and identify the one bit that's broken, and then say, "Okay, this is the thing that we need to do in order to-"

Giulia: And that's important too, and I need to do that too at times, but it took me some time to get to this other thinking.

That's actually why it took me quite a while to write this book. I really had to learn a different way of thinking. Also a bit more associative, I'd say.

Jonathan: When we feel ill or not able to perform as we expected, we often say things like, "My body's broken" or, "I'm damaged."

What's your view of that approach?

Giulia: It's almost always wrong, even with horrible diseases, and I'm not saying the body doesn't make mistakes. The body definitely does make mistakes. It's human after all. But the way we often describe it is like it's broken or stupid or dumb or aggressive even. With the immune system, you'll often hear in a doctor's office, you know, "Your immune cells are attacking your own body," and it sounds in a way a bit stupid and aggressive and unnecessary.

But what we know from research since the '90s is a very different picture. It's more that the immune system is trying to keep you safe all the time, and it's really all it's there for. That's its whole purpose of existence, and it does so eagerly. And sometimes, for example, when it experiences a horrible cold or something happening or notices your body is really not doing well or other genetic factors also, then it can go overboard a bit with that.

It can be overprotective. They want to do their best, but they're doing something that's not so beneficial, and that's happening a lot of the times when it comes to autoimmunity. And to see it like that is not only a nice story, it's also accurate to the research we have, but it's also helpful to the way people see themselves and treat their body when they have this disease.

Jonathan: Why does it matter? Why is there anything wrong with having this approach that says, like, "My body's letting me down"?

Giulia: Well, let me give you just the example I had with this when I really understood this. And I had a patient, and we diagnosed her with a chronic inflammatory bowel disease, and she had been in our hospital a few years earlier where she had a really severe EHEC infection.

So that's a toxic E. coli strain that is very dangerous. And she said, "Ugh, I have such bad luck. It's always the gut, and it's, like, acting up and doing all these horrible things." Of course, she was sad. That's not a good diagnosis to get. And I went in there in the afternoon, and I said, "I wanted to just talk to you about it again for a few minutes.

You've had this really severe infection a few years ago, and it is something that the immune cells see and witness, and they do form a memory. And when they have been through something like this, they are more likely to react with autoimmunity and maybe attack gut bacteria that aren't bad after all, just because they've seen something so dreadful, so horrible, almost going wrong.

And now they're just being over-careful. And while they're doing that, they're attacking all these things that when they just look a bit funny, they go off. So it is not convenient. It is not a good thing, but it is them really now being overly, you know, attached to you and trying to secure you." And she had a bit of teary eyes, and I think for her it was better to learn it that way.

And also when we look at all these additional therapies that are now being researched more and more when it comes to autoimmunity, different diets, you know, relaxation techniques or, you know, all kinds of different things for autoimmunity, it's all like a to-do list if you don't see it from the right angle.

But if you see it from the angle that the immune system is constantly checking on your body, how you're doing and adjusting its aggressiveness according to that, then all these things make sense because they give the signal and communicate to your immune cells, "Oh, I'm actually doing good."

Jonathan: Are you saying that your immune system is perhaps overprotective some of the time?

It's checking on you and figuring out how aggressive it needs to be, and if in fact it's on more than it should be, and this is your example with these sort of autoimmune situations where it's sort of attacking something that isn't actually bad. If you can just somehow calm yourself down, like be more relaxed, then potentially you're sort of sending messages to your immune system that maybe it can also be a bit more relaxed.

And that can genuinely change the way in which it interacts with, you know, whatever's triggering it and setting off this sort of autoimmune response?

Giulia: To be very clear, you cannot heal an autoimmune disease by just relaxing. That would be insane. There's always multiple causes and influences on diseases.

Usually it's multifactorial, you know? But one factor is also an interaction of the nervous system with the immune system. Those two communicate, and we know this through good medical research, and there are these studies with relaxation techniques, stress influencing the course of autoimmune diseases.

So it is one factor that we can influence, but there's also other factors like, as I said, maybe a viral disease has tipped it off in the beginning, or you're genetically more likely to develop autoimmunity because you lack certain signals or structures or have a little less of cells that calm the immune system down usually.

So there's always multiple factors, but one of them is also your body being in a good state and your immune system noticing that.

Jonathan: I think that's fascinating 'cause I feel like I was brought up thinking that is all crazy Californian woo-woo- ... to think that, like, your mental attitude could have any impact on your body.

I was definitely brought up with a very big divide between, like, the mind and the rest of your body, and-

Giulia: I think most of us were, and this is just what happens when research has the luxury of being more differentiated. Lots of research that I look at now is, you know, suddenly there's a gut-liver axis, there's a liver-brain axis, there's immune system-brain axis, there's a...

You know, all these axes that are now being called that, they're basically just saying, "Oh, now we have the luxury to see all these finer connections and influences as well." It's also a paradigm shift because we've had this time of, you know, separating everything in science, and we had to because everything was so, you know, before that medieval times and everything being a bit more like a story time or, you know, mystical.

And then we said, "No, let's separate it and be very rational," and to, in order to research it, we have to really divide it up and look at the singular pieces. And I think now we're actually doing an interesting step. We're now connecting those pieces that we were so eager of separating in the first place.

I find this an interesting time in medicine.

Jonathan: My wife says I'm a terrible patient. That whenever I am sick, I catastrophize. I'm like, "I'm gonna be sick forever. It's terrible." I also complain immensely about the fact that my body is letting me down. Why am I feeling like this? I can't do everything I want.

Which I think is learned behavior from my upbringing.

What should I be doing instead?

Giulia: The nice thing about being sick, or, well, it's not a nice thing, but it's the good to know thing, I would say is that all these things you're experiencing, for the most part, don't come from the germ that's infecting you.

The sore throat, the runny nose, the cough, the fever even, the microbe or the virus doesn't do that.

Jonathan: It's not coming from the infection?

Giulia: No, because it would really like to live there unnoticed, and that would be the best case for it if no one bothered and it could just be there and do its thing.

But who bothers is our immune system. It's saying, "Oh, I don't like the way this special microbe is treating my cells. I'm against that. I don't think it's a good match, so we should, you know, divide this up here." And in that case, it'll start popping some of the throat cells to get those out that have the virus in, and then protecting the cells around to not get the virus from the virus spreading.

It'll induce little wounds doing that, and it'll make the nerve cells more sensible with all the inflammation, so that's where your sore throat comes from. Or also the runny nose is a mechanism where when there's an infection or a bacteria or virus noticed in the cells, the immune system will trigger the blood vessels to become porous.

And through these porous cells, suddenly the fluids from the bloodstream enter the tissue, and that's good because the immune cells can come with that. They can go to the place where the infection is happening through those pores, and they get there, get to the trouble spot. But also all the liquids that are coming out of the blood are then creating this swelling and runny nose, and the runny nose will expel whatever is there, just like diarrhea does expel a bad germ or coughing does expel, you know, viruses in a load so that you don't all have to fight them.

You're just, you know, getting rid of them, have fewer of them after. And fever is also a way of the immune system really driving up its own temperature of the body with the help of the brain to then have the virus or bacteria feel uncomfortable with this changed temperature, and also tell other immune systems cells that are further away, "Oh, we're activating this higher temperature mode, so we might all get a bit engaged here."

Jonathan: So if these symptoms of... Let's start with the cold maybe. If the symptoms of the cold are, like, my immune system doing its job, should I be taking any medicines that might interrupt this?

Giulia: This is debated, and there's data on multiple aspects. And for the very first question was just should I take something like anti-inflammatory drugs when I have a cold.

Some research say don't because it might prolong the cold for another 24 hours, an estimate, and others say, oh, do because it doesn't really change anything, but you'll just feel better. Some things are a really good idea. For example, decongestant nasal spray because they'll actually, when it gets too bad with the nose and you can't breathe and eat and sleep, then really you should take some before it spreads to the ears.

Because the ears go through the same channel, and if it's all swollen up, they can't really air and clean out, and so then they'll have a problem soon. So the decongestant nasal spray, if you use it right, not too much, don't overdo it, don't take it too long, then it's a really good thing to do when you're sick.

But when it comes, for example, to things that tone down the gut when you have diarrhea, like loperamide, for example, it's the usual thing you take on travels or something, then you should really think twice. Because, as I said, diarrhea will expel the germs out and help the gut to get rid of them so they don't infect any more cells, or less at least.

And when you then take something that just stops the motion of the gut and just lets everything brew and lay around, then that's not a good idea, and we have data showing that it elevates your risk of post-infectual irritable bowel syndrome and also, like, having a bit more pain and, like, trouble after an infection.

So if you really need to take it because you just have to get on that plane or you're starting to be dehydrated and it gets really bad, then go ahead. But if it's not so necessary and you could just really have your gut, you know, sorted out for half a day or a day in the hotel room, then you might want to go with that, for example.

And it's a mix out of both for anti-cough medicine because in the very beginning, cough is similar to diarrhea where it really gets out some of the viruses and germs by coughing them out. But later on, it oftentimes will fuse into a more of, like, irritated cough where just the immune cells and the cells in the airways are so sensitive, every piece of dry air or little particle that you breathe in will then irritate them and make you cough unnecessarily.

And in that case, you can then grab a medicine. You know, I would, you know, put it in these categories.

Jonathan: I'd like to ask about the painkillers because that was less clear to me. So let's say I'm thinking about taking paracetamol or Tylenol.

Giulia: Yeah.

Jonathan: What on balance is that likely to do?

Giulia: And since the data is not really clear on that, I think everyone can still pick their choice, and also depending maybe on how bad it is.

If it's so bad that, for example, you can't really sleep, and sleep is very important for healing, or you just have to, like, get through the day, then I'd say go ahead.

Jonathan: Often you have this, like, paracetamol or ibuprofen as sort of, like, your twin drugs you can take. Are you as relaxed with the ibuprofen as you are with the paracetamol?

Giulia: It's a freedom of choice, I would say, at this point. I don't have a preferred one to advise. And people usually have one, so they say, "I react better to that and that," and then I would always go with this.

Jonathan: I was thinking back to what you were saying before about, like, rethinking the immune system. Like, I tend to think of the immune system as being sort of permanently at war.

Like, it's constantly fighting against all these things in our environment in order to keep ourselves safe. Like, is that the right way to think about it with, like, all our latest understanding of what's going on?

Giulia: Well, yes and no. There is this part of the immune system that really has to do all these things to keep unwanted microbes and stuff out, but then it's also in a way kind of old-fashioned, to be honest, 'cause we've had this research about, like, invaders and killer cells and so on in, like, times of the First and Second World War, heavily influenced by the war lingo.

And partly it fits what's happening there, but for some other parts, and actually quite large parts, it's not, and we have known, like, for a few decades now that the immune system is also really trying to keep us safe through other routes than just war and fighting. It is keeping us safe through, for example, cooperating with good microbes, which is a very important part, 'cause if they take up a lot of room, there's not so much room left for bad germs to land, you know?

It is saving a lot of energy by not initiating unnecessary inflammatory reactions by tolerating and just, you know, nurturing tolerance in order to have just microbes sitting there that don't do anything bad, that they are okay. Maybe sometimes they're a bit funky, but that's not a problem. And all of this it can only do because it constantly asks us how we're doing, gets to know us all the time, is curious and learning, and builds a memory and, you know, has all these experiences.

An immune system in our old age is educated and very different than one in the younger ages where it will just inflame and have a fever right away. And then in older age it'll say, "Oh, I know this bug. I don't even care to, you know, inflame anything or have a fever. Shoop, it's gone." Or something. Yeah.

Jonathan: In your book you use this term the microbe cloak.

Can you explain what this microbe cloak is and what you mean by that?

Giulia: Well then, what is a cloak? The fun thing is you can change a cloak, right? You can take it off and then you can put another one on, and if it's raining, you might want to use a waterproof one, and if it's really light out, you might want to use a very light, nice one or something, you know?

And this is the cool thing about bacteria and what actually our relationship with them is, because let's be real, from, like, those millions, billions of bacteria that are out there, very few make us sick. With viruses, it's the same thing. Each time we breathe, we breathe in hundreds, thousands of viruses, and they won't do anything to us 'cause they just really don't care to infect us.

To get the full picture, you would have to say they must have other jobs, and it can't be their main job to make us sick, and really it isn't. And when you look at bacteria, their main job, numerically speaking, just mathematically, is really borrowing some of their unique features, like giving them to us for free in, you know, exchange for maybe living on us for a couple of minutes, hours, or years.

And that is a nice thing because we can interchange them like a cloak, as I said. If we go to another country and there's suddenly a weird new food that we're eating, oftentimes on that food sitting ready to digest some of the fiber or particles are already bacteria. And while we digest, we keep them as for as long as we need them, and when we go back to our country, then, you know, after a while they're gone because we don't need them anymore.

And this happens also on the skin where there's bacteria and microbes that will produce antibiotics that will then fight other bacteria trying to get into their space. So this is what I mean by cloak. We have all these microbes sitting on us and micromanaging our surfaces.

Jonathan: I love hearing you talk about that.

To what extent is that just randomly happening, and to what extent is our immune system sort of actively managing this?

Giulia: The immune system's definitely there to pull some strings, I'd say. And I love this one paper where they had people put their hands into a jar of bacteria. I think it was E. coli that they put their hands in, and of course then the hand is full of bacteria.

And then they retest after a while, and they see that most of the bacteria are gone, and this is also because, well, the skin bacteria and then our immune system and cells producing antibacterial substances. So, you know, the body takes care of quite a few things if you let it and give it the time. And of course they have to work together.

The immune system will allow the bacteria when it sees that the cells are okay. So if there's a bacteria in the gut, for example, and it's producing short fatty acids that really nurture our gut cells, and the gut cells are actually feeling better, and they have more fuel and energy, and they look healthier, so to say, then the immune system will be like, "Oh, whatever's going on there, I'm not getting in it because it seems like it's a good deal."

This basically happens every day, every second in our gut all the time. Also with foods, if we're eating that or that, and then the immune system says, "Oh, we had some peanut, but you can be here if you don't do anything damaging." But then microbes sometimes do the opposite. They do damage our cells, and then the immune system will get a bit nosy.

It'll be like, "What's going on here? Call some colleagues of mine, we'll check it out, and then we'll all share our opinion and then decide whether we start an inflammatory reaction," for example.

Jonathan: So should we think about our skin and our gut microbiome as part of our immune system?

Giulia: Absolutely, and I think it's scientifically correct now and regarded as such.

Jonathan: And so how does our immune system tell whether this is a good microbe and I want it as, like, an extended part of my immune system, or this is, like, a bad microbe and I need to try and get rid of it?

Giulia: There are different immune cells, and there's different ways of how they look at us. And some will go with very basic ground rules.

Like, they'll say if there's a leakage of intracellular liquids, like, you know, the plasma of the cell basically running out because a cell is damaged- A cell wall was damaged by a microbe, for example. And this is a typical pattern where some sort of immune cell will go there and be like, "Whoa, why is there, you know, a cell leakage?

What happened here?" And it'll create attention, and it'll catch other immune system cells going there, and they will then, with their way of looking at cells, see if something's wrong. Other cells, for example, will attach to special receptors where there's always a tiny piece of protein showing what the cell has been doing throughout the day.

And if this protein suddenly is weird, like one that actually a virus made and not the cell itself, then those immune cells will say, "Oh, something's really wrong here." And other immune cells will have just receptors for typical patterns of microbial walls. So they'll say, "This is usually not a good microbe that I have learned, you know, to form this receptor against to notice it."

So there's very different ways of immune cells asking us and ourselves the questions, how are you doing? And then there's this conversation that all of these immune cells have with each other. Let's say all of these types are alarmed at the same time, oh, then it's really going down because then they're super sure that something's wrong, like with a viral infection, for example.

But if just one of them is alerted, and it'll ask all the others, and they're like, "No, you're maybe just a bit panicky. Everything here seems fine for us," then other immune cells will tone it down and not initiate an inflammatory reaction. So there's really this ongoing discussion and debate and researchers looking at that, like Aaron R Cohen, this is why I said in the beginning, describe it really more as a way of consciousness because in consciousness, in the brain, we network all these cells to create, you know, a neural network that is capable of suddenly saying, "I am well," or, "I am worried." And the immune system just does exactly that.

It connects cells that all have a different way of perceiving information, and then they will say, "Oh, I'm not well. I need an inflammation here, so let's initiate that." And then they have a go at it.

Jonathan: So are you saying it's almost like my immune system's making these decisions like a conscious thinking thing?

Giulia: Well, yes, 'cause it is a nice term to throw around, consciousness, but what do we base it on? We base it on how much information is connected and summarized into one. For example, with artificial intelligence, we say about 150 million connections are made to create AI saying, "You look handsome," or something, you know?

And so when you look at the immune system and the amount of cells, and then the number of connections that are made between all of these cells, it is much more than 150 million. So it's actually way more complicated than AI, and with that number, actually it gets much more close to the connections forming consciousness in the brain.

So this is why you can confidently say it is quite similar to that process.

Jonathan: That's really cool. I think I'm definitely coming away from this with a sense of how complex it all is. I'd like to come back to something you said a bit earlier, 'cause you said that the immune system can be sort of set too high and attack innocent targets.

What happens? What are you describing, and why does that happen?

Giulia: There's certainly the time when it just has an inflammatory reaction towards something, in a wound for example. That's usually good, but even there it can sometimes go overboard a bit, like when everything's already done and you're healing up, sometimes it overcompensates.

But then you have it also in things like allergies or autoimmune disease, and when I hear people say these things like, or promote supplements and like everything's just targeted for having a stronger and stronger and stronger immune system, I say, "Oh, I think you don't have the whole picture," because it's really not about just having the strongest army on the planet, but it's about having a balanced one.

If you had like security personnel around you and they were stoked up all the time, almost like on cocaine, be super aggressive and super strong, then this might lead to some risky situation. You really want them well-balanced and really analyzing the situation well before they overreact. So this is, I think, the same for the immune system, and if you have all these substances to stimulate it or let's just say sugar, because sugar gives it all the energy to produce more and more and more immune cells, and with more, more can go wrong.

And sugar also gives it a signal to maybe be a bit more pro-inflammatory because it can afford it. Studies show that over 20 years or so of people regularly drink soft drinks with lots of sugar in them, then they just have a higher risk of having, as you said, rheumatoid arthritis, for example. And so you don't want it on overdrive.

You don't want it doing too much. You want a balanced immune system. And of course, I want to really be clear, there's other ways to get those diseases, and it's not people's fault or having too much sugar that will then lead to them for sure to get this disease. So people have genetic disposition.

There's environment like air pollution. All these things can also lead to that, so it's not the only cause, but it's just one aspect you might want to be careful with because it pushes it in a wrong direction. And there's other ways when I think people say, "Well, should I not at all strengthen my immune system now?"

And here I would also interfere and say, "No. Oftentimes it's about not weakening it," because, for example, chronic stress really weakens it because the body uses all this energy for problem-solving, for ruminating, and then it takes it away from, for example, sleep and forming ripe, good immune cells that regulate the immune system.

So when there's a cold season and everyone around you is sick, you might as well strengthen it with some substances. I'm okay with that, you know? But for the most part, it's about knowing a bit about it, like having a balanced body, supporting it, not weakening it.

Jonathan: I think for many people when they're thinking about their immune system, they immediately go to like these supplements that say they're going to boost your immune system.

Firstly, do any of them work? And secondly, are they all a bad idea? Because boosting your immune system, you said, like, potentially actually is not what you're looking to do.

Giulia: So they're not generally a bad idea, but sometimes the focus is wrong here. People sometimes lose sight of the big chunk of, like, the 80% stuff, as I like to call it.

Those are the things maybe your mama already told you, you know, get enough sleep, have a healthy diet, don't stress too much, enjoy life a little bit, like, you know, these things where it sounds so basic and simple, but actually just to take care of these things is already helpful and it's the most effective.

And we know this from so much research and studies now that I don't think there should be any doubt.

Jonathan: You've mentioned multiple times, actually, in our conversation this concept that stress can, you know, impact my immune system, maybe weaken it or maybe sort of cause inflammation. And I guess my question is, firstly, did I hear that right?

Giulia: Yes, absolutely.

Jonathan: And then I guess more interestingly, what can people do to manage their stress better in a way that could help to, like, balance my immune system, you know, reduce a little bit those bodyguards going wild, but or equally well, I don't want them to just, like, go off on holiday and leave me unprotected.

Giulia: We can't eliminate all the factors from the outside world, and sometimes they're too heavy. But, you know, for some aspects we can be mindful of. And by just, for example, knowing how stress affects the gut, when you are really stressed, the gut, for example, will tone down its work. You can actually see it with a camera.

The walls of the stomach, for example, turn pale, paler than when you were relaxed. And this is because the blood flow is being reduced a little bit. So there's less blood, so it looks less cheeky pink, it's more whitish. And less blood flow means we have less, you know, nutrients, energy coming in, for example, to have immune cells coming with the blood or, for example, to have mucus build up because that's a process that needs proper, you know, blood flow and everything to be developed fully.

So when you have less mucus barrier, your protection layer is a little bit less so bacteria and particles from fruit, like food, they can get to your cells a bit closer and maybe sometimes irritate them even. But if it's just for a day or a few hours, that's no problem because that's just a good deal.

That's just, you know, trade off a good sacrifice to solve a stressful problem. But if this is going on for days and sometimes even weeks, you're really taking advantage of an organ being good willing, you know, giving up its own work and stuff just for you to solve this horrible situation. And then the gut gets problems and that's when, like, stress-induced gut problems often start and arise from that mechanism being taken advantage on or going on too long. Oftentimes we see our outside demands and outside world so clearly that it's easy to fulfill all of them, but we don't know a lot about what's going on inside while we're doing that.

For example, during a stressful day, at least for lunch break, for 30 minutes or in the afternoon, have some downtime. Really eat calmly. Don't stuff your mouth hole, as they say. You know? Really enjoy eating and being there, being present and saying, "You have pushed back all your work this whole morning because it was so stressful.

Now I'm giving you this time to really do your thing, and then we'll go back to my job afterwards." These things help, and sometimes it's things like actually looking out for your breath, because breath is a great mediator between the outside and the inside world, and it can really tell the brain, "Oh, now we can calm down," when we breathe slowly, for example.

So sometimes it's so simple. It's just one minute at 12 o'clock and one minute at 4 o'clock during a stressful day, for example. I'll take and just breathe slow for a minute, and it takes me to a place of, like, more calm and serenity. And it's just this simple, short minute. And in studies it shows that you have reduced stress hormones if you just take it.

Jonathan: And so Julia, you're saying even just, like, this minute twice a day to slow down my breath can reduce my stress in the moment, and that over time that can have an impact on whether my immune system is sort of, like, dialed up too high or it's at a sort of more steady level if the rest of my life is stressful, which I suspect for almost everybody listening to it, they're like...

They'd say, "Oh, yeah, my life is stressful."

Giulia: It can take the edge off. It can't take away all of your stress, but it does shift a little bit in an important aspect, which is value. Suddenly you give your body this value, and even if it's just those two minutes, you say at least it's worth that.

And for some, for a lot of people, that sometimes is more than they had before. So two minutes is more of a value than they had before. Isn't that insane? What does that tell us about our relationship to our inside world?

Jonathan: What happens if we're not getting enough sleep?

Giulia: Well, quite a lot of things. Well, one thing as we were just talking about is that sleep is the time when most of the immune cells are being produced, and this is because during sleep we're not being disturbed by all these foods or having to run or metabolic challenges, stress, signals from the brain disturbing everything.

No, we're in complete harmony with just regulating our insides perfectly well. And during that time, cells make remarkably less mistakes. So it's smart of them to pack all their processes and dividing and producing new cells, put a big chunk of that right there in the middle of sleep so that they're not being disturbed, and need less energy to fix mistakes later on.

So this is one thing that's happening there, and also a thing why, for example, shift work can then be a bit risky for your risk of developing cancer, for example because if you disturb this process all the time and cells don't have this calm space to divide with less mistakes, well, then they can make more mistakes.

It just adds up over many years of working, not within, you know, a week or a stressful year even more so.

Jonathan: We get this vast amount of data from everybody who are ZOE members. Almost everybody reports the fact that their sleep is not as good as it should be. I think we all know the things in modern life like phones and TVs and electric lights that I think mean we tend to sleep less than our ancestors would.

Does that mean that if they were able to sleep better, that that would probably help improve the sort of the balance of their immune system?

Giulia: I mean, it depends on how severe your sleep disruption is. The immune system needs especially the first half of the night because that is when there's most deep sleep, and deep sleep is the part of the sleep where the cells have this perfect window to multiply.

And then the second half of sleep is more REM sleep, processing feelings, finding new emotions. These kind of things happen more there. So if you're good in the first half, then that's good for a lot of physical processes, like bodily things happening. Most people have rather a hard time with the second half of the night, or they wake up and then they have a hard time falling back asleep.

And I think, well, we weren't even done with listing all the things sleep is good for, you know, pain tolerance, hormone balance, digestive health because of replenishing of the cells there as well. So it could go on and on, and mental health, risk of dementia, blah, blah, blah, blah. But the funny thing here is people have all these advices now.

They have social media and health information with what you should do. Do this, do this, do this, do that in order to sleep better. And, you know, then they also get scared, "If I don't sleep well, I will get this, this, this, this, this." And the ironic thing is that sleep is just really out of their territory.

It's not the territory of the conscious mind who lists all the to-do things. It... I mean, it can do that before you go to bed. It can watch not to use the cell phone, not to not eat too late, like all these things. But sleep in itself is really the other parts of the brain taking over, and also the consciousness being able to give them this responsibility and let go of it for a few hours.

These areas that just have a very different way of going about things and are actually quite successful at it. So our consciousness compared to them is so bad at regulating our body, blood pressure, breathing, and so on. It, you know, regularly disrupts it in a negative way, to be honest, by all these stupid thoughts and thinking and responsibilities.

And when they have time without it, oh, they're so relieved. They can just do their thing.

Jonathan: You know, there'll be a lot of people listening who, you know, really struggle with sleep.

And one of the challenges is that, you know, as you're going towards bed, you're actually really thinking about it, it's become this almost, like, this mountain you've got to climb, and that therefore makes it hard to get the thing.

And I guess I always worry that listening to the, you know, something like this, they're like, "Oh, but now I know it's even more important to get to sleep," and actually, potentially you, you know, we're increasing anxiety about it.

Giulia: Well, yes, and I think in a way this is an indicator for how estranged the conscious parts and the outside world-dealing parts of our thinking and brain have become to, like, the more bodily, earthy parts of our brain, 'cause there are different parts, and how estranged our, like, whole perception of life and world and ourself has become to all these parts of ourselves that are just not connected to the outside world, that are not relying on getting up at 6:00, but they're actually just worrying about how is the cell doing then, how are the cells doing then.

Like, the really, the foundation of being alive, and these areas that run very differently and that don't have to do with, you know, if you're able to perform at work or something. And sometimes it becomes even hard for people to imagine that there's this part of ourselves that is not about performing and that is not about fulfilling and not about to-do lists, and it seems like those two parts of ourselves have really a hard time getting along nowadays.

Jonathan: It's really interesting. I think in a world before electric light and phones, basically it got dark, it got really boring, there's nothing to do, and I think, you know, you don't have that stimulation and I think you sort of fall, tend to fall asleep, like our children do. But you never had to, like, be well programmed to say, "Ah, I've got all this stimulation, but I need to go to sleep, so I'll go to sleep," so sort of not built in.

So much of what is difficult in modern life is where, you know, the environment is just not well set to how we just evolved to be.

Giulia: Well, but that's just a process. The body is very good at adapting and finding always new ways, and I think probably always in history there was something new coming up that it really wasn't, you know, prepared for and just sort of, like, adjusted and went along with it.

And I think we'll be able to do that here too, but I think it will be problematic if we tune out the knowledge we have about the body, if we just try to stuff it into this, you know, four-corner product of modern life, then it won't work very well, and we already see the indicators for that everywhere, sleep problems included.

But if we understand it better and move along with it more smartly, then we'll find new ways, then we find good ways, and then we'll make also modern and innovative things happen and work for us and not the opposite, us working for them.

Jonathan: And Julia, if I go back to sleep, you were talking about how important it is for my immune system in creating these immune cells.

Do naps count?

Giulia: Yes, but if you have a hard time sleeping during the night, then sometimes advisable to cut out the naps so that you build up more sleep pressure, as they say, and then you have an easier time really being asleep during the night. But if you've had a horrible sleep and, you know, you're carrying it through the day, then a short nap can be a really good idea.

And that is, for example, one thing that I think we should make the world adjust more to the body and not the other way around. For example, young parents when they go to work, but they've really had a horrible night and they... If it's possible to have a room where they could just lay down for 15 minutes and not be judged for it, then the rest of the day they would be able to do much better work, be much more, you know, bringing things forward, being effective, and rather than just pretending they're a machine and trying to hide their imperfectness.

No, work with that you're human and that actually when you understand yourself, you can get a lot out of that.

Jonathan: As long as it's not ruining my ability to sleep at night, napping can be good.

Giulia: Yeah. And we see that there's also this built-in biological clock, as you can say, where it has proteins that fall apart twice a day.

So once is of course when we go to sleep, but then the other one is especially at that nap or siesta time in Southern Europe, where so two times a day there's this offered platform to us where we could actually fall asleep. And if there's enough reasons to do so, then we will.

Jonathan: Julia, what do you do to make sure you get enough good quality sleep?

Giulia: I realize that I really have to tone it down in the evenings. I don't do late exciting gatherings if it's not my birthday or anything, you know. That really makes me sleep not so good. I don't eat too late. And then during the day I try to come down once or twice. Like really, as I said, I usually try to do the 12:00 and 4:00 where I just have a minute, or sometimes I'll just like even sit and just breathe and take a breather and just calm down because I think it's so unrealistic to have your conscious mind being constantly super activated and taking all the responsibility the whole day being at 150 and then at 10 o'clock in the evening you expect it to go to like chill out level.

How is that supposed to work? So I really try to tell my body, you know, it's good that you have this, but it's not always necessary. You can be brainless for a minute, you know?

Jonathan: Amazing. Can I move on now to diet that you mentioned? And obviously we talk about nutrition all the time on this podcast.

If you were going to give us like a high level explanation of thinking about, you know, the food that is going to sort of balance my immune system, what would you be describing?

Giulia: I mean, we have these typical formulations where we say, you know, Mediterranean diet, have some fibre so that your gut bacteria are well-nurtured, that they don't eat your protective mucus and stress your gut lining, and that stresses your immune cells, like things like this.

It is also about good fats, but that is included in the Mediterranean diet, and about not, you know, riling it up, as I said, with sugar, for example. And then we have some foods that are declared as pro-inflammatory. Usually with all of them it is really about the amount. If you have too much of them, like peanuts, sesame oil, I suppose because of the omegas in there, too much like meat, butter, all these things that drive up your blood sugar, pastries.

Like it's a list and I really don't usually like those lists too much, but you can pretty much tell it's the old story about having some veggies, some fruit, and some like balanced carbs and good fats.

Jonathan: What about exercise, which I think a lot of people will be surprised is linked to your immune system health.

I think that no one will be surprised listening to this that it's good for your health overall. But why is that good for my immune system, and therefore what kind of exercise should we be doing?

Giulia: Well, one interesting factor that the immune system will even use for itself or manipulate in order to, like, have better outcomes is just having a stronger, faster heartbeat.

When you get sick, you notice that your heartbeat will get a bit faster, and well, it does make sense because the immune system, the cells, they travel through the bloodstream. So if you have more pumping going on, they get everywhere faster, and they can, you know, be pumped around more often and visit more areas in the same amount of time if you just pump a bit more.

And the important thing about exercise is that you have immune cells in the venous system and lymphatic system of your tissues, and by activating muscles, you press them up back into the circulation from the tissue. So you give it a little boost, which otherwise happens just in a longer period of time.

You boost it while moving because you pump everything faster and with more force.

Jonathan: And so does that mean you should be doing exercise when you're sick?

Giulia: No, not when you're sick, not necessarily. That can be bad for the heart, especially when you have a viral infection. But when you exercise regularly when you're healthy, then you train your heart and your lungs to pump around stronger, and also it makes the whole tissues being have more blood flow, so more immune cells observing and checking if everything's okay.

And in case you are sick, you have trained you know, the whole system to get along with this rise in blood pressure and heartbeat and yeah. And also what we see is muscle. The effect of muscle on the immune system is really interesting.

Jonathan: What's that?

Giulia: Muscle is a big amount of our body. Well, we have so many big muscles, and they can influence the immune system by regulating it down.

After exercise, for example, muscles tend to be a bit irritated, and when you exercise a lot, they will learn to reduce this inflammatory reaction towards a muscle being maybe a bit strained, like aching after exercise. If you have this effect over and over again, the immune cells will start to notice, okay, there's a little bit of aching and maybe inflammatory processes in the muscles going on after exercise, but we'll fix it and then we'll tone it down.

So they practice this process of toning it down again and again and again, and that is important to have a balanced immune system that doesn't overreact. But also, you know, muscles regulate blood sugar and do those, so lots of indirect effects also.

Jonathan: That's fascinating. Yeah. You're saying that if I'm doing exercise regularly, then there's many ways in which it's good for me.

It's like making my heart stronger, which will be really important if I'm sick. It's creating better blood flow across my body so my immune system is able to sort of see everywhere.

But also actually I think you're saying that for my muscles, if I'm regularly doing exercise where, you know, they're sore and aching afterwards, like, you know, it happens to me after I go to the gym, but I guess if you have a run, you're actually saying, wow, that might be good, 'cause your immune system is sort of learning, okay, I'm getting to start to realize I should lower my immune system 'cause I don't want to overreact because this is just a regular sort of normal thing.

And this is part of what you're describing that often one of the things we need to do with our immune system is not to boost it. Quite the reverse. We actually want to get it to sort of relax a bit more into a more neutral setting.

Giulia: And be able to do that a bit faster sometimes. Sometimes just to like cool down faster.

Like in the office when you get a really stupid email and you suddenly are able to say, "Ugh, I'll just reply later," instead of going on about it for two hours inside of yourself. So the immune system it's the same way. When it gets, you know, fed up with something or insulted, then it can either be like, "really stupid, but we'll take care," and like calm down, or it can be inflammatory about it for, you know, another two days.

Jonathan: You don't want that. Often I feel calmer after I finish an exercise session. I tend to do a gym session, like, during the day within work, and I notice often I feel calmer even though in fact I've obviously been straining myself much more than just, like, sitting in front of a desk, you know, usually looking at a video screen talking to people.

What's going on and how does that tie into what you're describing about the interaction with, like, calming down my immune system?

Giulia: Well, this is not only about the immune system. This is also really about the brain being in the body, having all these things happening, like playful stress. The experience the brain just had was similar to a disease.

Like, it had a high temperature when you were doing sport, it had an elevated pulse, it had an elevated blood pressure. It maybe even had, like, a surge of, like, stress hormones. Like, all these things that actually would -- should be horrible, you know? But it was sort of a playfulness because it's not really a fever, and it's not really something anxiety-inducing that drives up your heart rate, and it can all stop the moment you're done.

You can decide when you're done. So in a way, this is kind of, like, good for the brain to experience that it can be out of its comfort zone but then come back. And especially also the change in temperature as we see in sauna, for example, and then just coming back with nothing bad happening has an effect that is calming.

And so it's not only sports sometimes that can do this. When you do breathing exercises where you breathe really fast for a while and then you breathe really slow, it's also in a way the same thing. You change the pH value in your blood, and this is stressful for the body and weird, but then you just go back to normal.

And so in a way you tell your body, you know, "I can do this." And then the other aspect is sports and exercise really influencing your brain chemistry, so you see different receptors being expressed, different way of handling some transmitters after sports. Just, you know, the brain is so isolated up there, when it gets really into contact and really has to deal with reality and the muscles and actually do movements that work, otherwise you drop the cup if you don't hold it right.

It's sort of like a good thing to get out there into the real world for the brain. It has this effect of, like, lifting heavy things when you're stressed. People, like, in the army are being trained when they have a really stressful situation to -- that they couldn't really process in the moment to, like, calm down to, like, lift something heavy or just hold something heavy or do breathing exercises to really get into the body and connect the brain with the physical reality to calm down and not by just laying down and doing nothing.

Jonathan: You're describing this positive impact for my body and my immune system. Are there particular types of exercise that are gonna be much more effective than others?

Giulia: Well, what we see is that the different types of exercises have different effects. So now strength training is all the rage, and people talk about it all the time, and this has a good reason for it, because when we build a lot of muscle, they can regulate our blood sugar level, for example, better, and it has also more measurable effects on, as I said, like brain receptors being expressed when you do strength training.

When you do other, like aerobic exercises, durational, like jogging for half an hour or longer and you would be able to talk while you're doing this, this has other effects. It will, for example, train your heart and lungs a bit more, and this can also be good against things like anxiety, because anxiety can develop just by your body suddenly having a faster heart rate, breathing a bit faster, and this slows down when you have exercise that makes the heart stronger, so it doesn't have to beat so fast.

So there's multiple aspects that come from different types of training, and I would always encourage people to really try out and just see for yourself when you feel best. Because that's also the downside of sports. People do it, and then they hate it, and then they just stop doing it because it doesn't feel good.

So I think the really first thing to start with is finding something that feels relatively good and then stick with it and then go from there, you know?

Jonathan: Is there anything that we haven't discussed that you'd really like to mention to someone who's thinking about how they can keep their immune system better balanced?

Giulia: The only thing I would really want people to know is just that they have this genius side of being a living being, and that this is also something, and that this is counterweight to this loud, noisy, challenging outside world that is good to have as well, but, you know, have this counterweight and know more about it so you can actually really feel and get into that.

I think that's a very good antidote to a lot of things we're experiencing in this time

Jonathan: Amazing. I'd like to do a quick summary of maybe some of the highlights on what we've touched on. Please correct me if I get any of it wrong.

Giulia: No, I'm curious now.

Jonathan: The thing that is most, like, lodged in my brain is this amazing fact that you said that if you keep drinking, like, sugary drinks, then actually over 20 years you're basically going to have this, like, higher level of inflammation.

It's gonna boost, like, these immune cells, and actually you're more likely to get an autoimmune disease like rheumatoid arthritis. So it's amazing this, like, direct link just from, like, having more sugar.

Giulia: Diabetes and depression also, by the way.

Jonathan: The other thing I'm really struck by is this idea that the whole language that we use to describe the immune system might be a product of the time when the scientists were first understanding it.

It was, like, at the time of World War I and World War II, and so all the focus is on sort of killer cells and thinking about sentries and things like that. But actually, a huge part of what the immune system is doing is sort of cooperating with these microbes, looking at what's going on, and actually doesn't sort of shoot first and ask questions later.

Actually, it's sort of looking at what these bacteria are doing, being quite thoughtful and deciding these responses. And in fact, the way that you think about it is you think about us as having this microbe cloak around us. Very few of these bacteria are making us sick, and actually many of them might be, like, helping to look after us, which is a completely different way of thinking about it, which I love it.

Then you talked about rethinking what happens if you're sick. And so don't think about all your cold symptoms as being caused directly by this infection. Actually, this is your immune system helping to look after you, and that can make you feel better about it. And that also means be thoughtful before you try and get rid of all the symptoms.

So I am allowed to take a decongestant if I can't sleep, which is great. You know, I can take a painkiller if it's really getting in my way. But, you know, the other example you gave was like, if I have diarrhea, you should really try and let that happen because this is just getting rid of this pathogen.

And similarly, you know, when I've got a runny nose, actually it's doing a great job getting this stuff out. So don't be so hard on yourself. And then I think we talked about like what are the specific things you can do, not to boost your immune system, because you don't want that, but actually to balance it.

And I think you have this really broad set of areas. You started with stress, which is interesting that this is actually really important. And you can see stress. You said like your stomach will look paler. You know, I obviously most of us don't have a tube to put a camera inside your stomach, but you can actually see it.

And therefore, you know, your advice was quite simple. Have some downtime at lunch, like have a proper break. And that for you, just like one minute of breathing slowly at like lunchtime and 4:00 PM makes a big difference to reducing that stress. Talked about sleep. And I learned this amazing fact that deep sleep in the first half of the night is when most of my immune cells are being made.

So it's really important. But even a short nap can be good if I haven't had enough sleep. And, you know, one of the key things that you do also is like think about not eating too late, not being so excited at the end of the day that you can't sleep. Diet, obviously. And I think that what you discuss is very much the sort of patterns that we talk about on this podcast a lot.

And then finally, we talked a lot about exercise. And I think what's really interesting is it's not just all the health benefits we think about, but actually it's really going to help sort of balance your immune system and have it in better shape when it is needed. And that you want to do both strength training, that's good for muscles.

You talked about the way in your muscles can be really important for immune system, which is amazing, but also aerobic, because that's not only good for your heart and your lungs, but actually it can also be lowering your anxiety, you know, as you get into it. So there's this sort of all round somehow being more balanced as opposed to going and like finding a supplement that says it's going to boost your immune system.

Because actually, you know, my, if I have one takeaway, it's like you don't want to boost your immune system. You want it to be quite calm, but ready to go into action when needed.

Giulia: Yes. Perfect.