ZOE Science & Nutrition - Recap: What is inflammation and how can I control it | Prof. Philip Calder

Episode Date: January 21, 2025

Today we’re discussing inflammation. We hear this word a lot from guests on the ZOE podcast. It’s always coming up when we ask questions about health conditions like Alzheimer's, cancer or heart disease.  It’s clearly very important, however many of us still don’t fully understand what inflammation really is. Professor Phillip Calder is here to break down inflammation and share tips on what we should eat to keep it in check. Philip is Head of the School of Human Development and Health in the Faculty of Medicine at the University of Southampton. 🥑 Make smarter food choices. Become a member a zoe.com - 10% off with code PODCAST 🌱 Try our new plant based wholefood supplement - Daily30+ *Naturally high in copper which contributes to normal energy yielding metabolism and the normal function of the immune system 📚 Books from our ZOE Scientists: The Food For Life Cookbook by Prof. Tim Spector Food For Life by Prof. Tim Spector Every Body Should Know This by Dr Federica Amati Free resources from ZOE: Live Healthier: Top 10 Tips From ZOE Science & Nutrition  Gut Guide - for a healthier microbiome in weeks Have feedback or a topic you'd like us to cover? Let us know here Listen to the full episode here

Hello and welcome to ZOE Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today we're discussing inflammation. I hear this word a lot from guests on the ZOE podcast. It's always coming up when I ask about health conditions like Alzheimer's, cancer or heart disease. It's clearly very important, however many of us still don't fully understand what inflammation really is. Professor Philip Calder is here to break down inflammation and share tips on what we should eat to keep it in check.

Can you explain in simple terms what exactly is inflammation, how it's different from immunity, and why you're saying it's not necessarily always a bad thing. Yeah. So immunity, our immune system, is the way we defend ourselves against harmful things in our environment, particularly things like bacteria and viruses. Now, immunity is very complicated, very complex, it's very sophisticated and it involves many different things happening in the body, many different cell types and events occurring. Inflammation is the first little part of the immune response. So immunity

is sort of like an umbrella of very complicated but joined up events and inflammation is just part of what's under that umbrella. So we shouldn't mix up inflammation and immunity. Now because inflammation is part of immunity, it's actually designed to help us. It's designed to be part of our protective mechanism. So inflammation is really the first thing that happens when we get exposed to something harmful and that could be an infection, it could be an insect bite, it could be a paper cut. So the things that people experience when they get a paper cut or even a more serious cut, you know, the pain, the redness, the swelling, that's inflammation.

So that's designed to help us. So it's something that happens in a helpful context. But it turns out if it's not regulated properly, or if it's happening in the wrong place at the wrong time, that's when it becomes harmful to us. I understand most of us living in a sort of Western lifestyle today probably have higher levels of inflammation than we should. What is this what's the risks as a result? Arthritis, multiple sclerosis, type 1 diabetes. These are diseases that clearly involve inflammation gone wrong and if you

measure chemicals in the blood of people that are indicators of inflammation, in those patients the levels of those chemicals are very high in the blood. You can measure the inflammation of somebody with a blood test, that gives you a real answer. There are chemical readouts in the blood that are elevated, that are higher in someone with an inflammation in the joints, for example, like arthritis. Is there one particular thing you look at or is it a set of things? So the most common marker is a protein called C-reactive protein or CRP.

That's a very good indicator that someone is inflamed, but there are others as well. So in these disease scenarios, we would consider that to be high-grade inflammation, so the levels are very high. But we also have other conditions where there is elevated inflammation, so too much inflammation, but not at this really super high level. So we call that low-grade inflammation. Of course, the inflammation in arthritis and so on has been known for decades now, but this phenomenon of low-grade inflammation has really only

been known for about 20 years, I guess now. And it turns out low-grade inflammation is part of many common diseases that people wouldn't think of as inflammatory diseases. So things like heart disease, for example. Heart disease. Heart disease, obesity, type 2 diabetes, even dementia. So these common diseases are linked with this low-grade but persistent inflammation. So that's part of the risk profile if you like for these conditions. And is it like one magic pill? Like if I take, you know, we often talk about extra virgin olive oil as being very good for you. Does that mean if I'm taking a shot of extra virgin

olive oil three times a day, like that will solve my inflammation like a pill from the doctor? Is it as simple as that? I wouldn't prefer to think of it like that. I mean, I would prefer to think of it like that. I would prefer to think of a long-term dietary shift away from things that are considered to be less healthy. And I mentioned in general what they might be in the context of this post-pandemic inflammation and a move towards things which we think are more healthy. And olive oil, particularly extra virgin, would be part of that. More micronutrients, I mentioned vitamin C, that would be part of that.

More omega-3s would be part of that. More fiber would be part of that. People know what extra virgin olive oil is, they know what nuts are, that was really clear. And I know you've done a lot of your own research around omega-3. Could you tell us what omega-3 is? Because I don't see that on the shelf like I see olive oil. Yeah, so you do see it on the shelf. It's just you have to go to a different shelf because you'll find salmon on the shelf in the supermarket. So when I talk about omega-3s, I'm mainly talking about the fish sourced omega-3s, EPA and DHA. So omega-3 is a general term for a group of fatty acids.

EPA and DHA are a type of omega-3. They are, as I mentioned, sort of uniquely linked with fish and other seafood. They seem to have quite pronounced anti-inflammatory roles, both if you put them in a meal, they will help to mitigate this meal driven inflammation. If you have this inflammation already going, be it high grade, but that's a disease like arthritis or this low grade persistent inflammation associated with aging, are there dietary components that can dampen that inflammation? More importantly, are there dietary components that can help you resolve the inflammation?

There's lots of things in the diet that are anti-inflammatory. They include omega-3s, which I'll come back to shortly, but also some of the vitamins, vitamin C, vitamin E are anti-inflammatory. Lots of the polyphenols from plants, so the things that give fruits, vegetables, berries and so on, their colors, they're also anti-inflammatory. Things in nuts are anti-inflammatory. Gut microbiome is also a driver of inflammation, but also could be anti-inflammatory if you get it right.

So there's lots of things in the diet that we can use to mitigate ongoing inflammation. I think these omega-3s EPA and DHA that come from fish, and they're also in fish oil supplements by the way, so people can go to a different shelf and get some EPA and DHA. And we might want to consider that in the context of people who choose a vegetarian or vegan approach. We've been working on EPA and DHA for 30 years now. They are anti-inflammatory. Okay.

That's clear. Lots of experiments show that. But the really interesting thing has been discovered in the last 15 years or so. This process of resolution of inflammation, the turning off, you know, flicking the light switch off if you like, involves chemicals again. So everything in the body is involving chemicals, sending signals. Researchers in Boston discovered that some of the key chemicals in resolution of inflammation are actually made from EPA and DHA in the body. So EPA and DHA are the substrates, the starting point for making chemicals that turn off inflammation.

People have studied omega-3s, EPA and DHA in arthritis actually since the 1980s. And it's well described that high levels of EPA and DHA as a supplement can help people with arthritis in terms of painful joints, tender joints, stuff like that, morning stiffness. And everyone always said, this is an anti-inflammatory effect. But actually, if you think these are people

who've already got high grade inflammation, I think what's happening is EPA and DHA are acting to resolve the inflammation, so actually to take that high grade and bring it down a bit. And that's why people with arthritis benefit from EPA and DHA. I imagine someone's listening to this and saying, I want to understand how to make some shifts to my diet in order to reduce this inflammation. Maybe starting with the sort of omega-3 and oily fish, I know that's your big focus. How strong is the evidence in your opinion that, yes, if you're willing to eat fish,

you should be adding oily fish to your diet? Will it make a difference? For me, the evidence is very strong. Okay. Yes, we have animal studies, we have all sorts of studies, but I'm mainly interested in human evidence because doing something in a laboratory in some mice is one thing, but we need human evidence. And in human research, in nutrition, we really, in general, we have two types of research.

One is where you look at diets, foods, nutrients, levels of nutrients in people's blood, and you track what happens to those people over time. So, you know, we call that epidemiology. The epidemiology of omega-3s is extremely strong. In other words, people who eat more fish, or people who eat more EPA and DHA, or people who have more EPA and DHA or people who have more EPA and DHA in their blood have a much better long-term health outcome. Less heart disease, less dementia, some cancers, less cancer, less metabolic disease, all that stuff. So the epidemiology is very strong.

The other type of study we have is treating nutrition a bit like a pharmaceutical, so a randomized control trial. Typically these are smaller in size and shorter, so they might involve tens or hundreds of people. But I think if you step back and look at the really important things like heart disease, for example, even from randomized control trials, there's pretty good evidence that higher intake of EPA and DHA reduces risk of heart disease and mortality from heart disease. And certainly they impact beneficially lots of the biomarkers that tell you about risk.

So I think for me, the evidence is quite strong and I personally would recommend that people should incorporate these sort of fatty fish in their diet if they can. I've been part of quite a few conversations with Tim and Sarah talking about the fact that a lot of oily fish today would come from salmon which is now factory farmed and very different from the sort of fish that we would have got in the past. And I know that Tim is quite skeptical about this because he feels that like there might be a lot of other reasons to feel that this is not really so good. How do you think about sort of the sort of factory farms salmon that you would actually

probably get if you went to the grocery store? Yeah, I think that's a great question. And salmon, I think is a really good example because salmon farming is a massive industry and probably most of the salmon that's available in the supermarkets is farmed salmon. People will be familiar with fish oil, which is, you know, they'll think of an omega-3 supplement that they can get from a chemist shop or, you know, a supermarket or online. And you know, fish oil contains EPA and DHA, these really important omega-3s, okay. Now in the wild salmon eat other fish and they get EPA and DHA from their diet by eating other fish.

So if you farm salmon traditionally you had to give salmon EPA and DHA in their food otherwise they didn't grow well and they didn't stay healthy. And the biggest user of fish oil is the salmon farming industry. That uses something like 75% of global fish oil is actually used in salmon farming. Okay, now first of all, that is a limited resource. And you could argue if it's so important, why don't we give it to people instead of the fish?

But the fish need it if we're gonna farm them. So it's a limited resource and it's also expensive. Okay, it's a commodity. It's much more expensive than vegetable oil, for example. And that's because it actually comes from other fish. And that's because it comes from fish. So you've got to invest in the production of fish oil. The research behind fish farming has been trying to find out what happens if we give salmon less fish oil and replace it with vegetable oil. So it's well described that salmon can still grow and do well if you give them less fish oil than they used to be given.

And you replace that with vegetable oil. The consequence of that is farmed salmon have less EPA and DHA in their flesh than wild caught salmon. A farmed salmon now will have less EPA and DHA than a farmed salmon did 20 years ago. So that farmers are figuring out ways to make this more profitable. The industry has found out a way to reduce its reliance on EPA and DHA and therefore reduce the cost of farming salmon, I guess. So one interpretation would be the overall health benefit is less from a farm salmon now than it used to be, let's say 10, 15, 20 years ago, and less than a wild salmon.

However, farm salmon still is a good source of EPA and DHA. It just doesn't have as much as it used to. Thank you for listening to today's recap episode. I want to take 30 seconds to talk about something that's not talked about enough. Menopause. Over half the people on the planet experience perimenopause and menopause. Yet symptoms are often misunderstood or dismissed. At ZOE, we're moving menopause research forward. We recently conducted the largest study of menopause and nutrition in the world.

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