Updated 13th March 2023

How to maximize health in your later years

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    Why are some people fit and healthy in their later years while others become increasingly frail?  

    Researchers from King’s College London have been following thousands of twins for 30 years in an effort to understand how each of us ages differently. And some of their findings will surprise you!

    In today’s episode, Jonathan speaks with Claire Steves to better understand what all this means — shedding light on how aging works and what we can do about it.

    Dr. Claire Steves is a professor at King's College London, a medical doctor, and the clinical director at TwinsUK.

    We have a favor to ask. ZOE's working on a number of new initiatives, and we’d love your input. If you could take a few moments to fill out this survey, we would appreciate it.

    If you want to uncover the right foods for your body, head to joinZOE.com/podcast and get 10% off your personalized nutrition program.

    Episode transcripts are available here.

    Find Claire’s publications here.

    TwinsUK is the United Kingdom’s largest adult twin registry.

    Follow ZOE on Instagram.

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    ZOE Science & Nutrition

    Join us on a journey of scientific discovery.


    [00:00:00] Jonathan Wolf: Welcome to ZOE Science & Nutrition, where world-leading scientists explain how their research can improve your health.

    Why do some people remain fit and healthy in their later years, while others become increasingly frail? Science has been searching for answers. Researchers from King's College London have been following thousands of twins for 30 years in an effort to understand how each of us ages differently. 

    Some of their findings may not come as a surprise. Obesity, activity levels, and lifestyle choices play a huge part. Other discoveries are startling. Their tests demonstrated inflammation levels rising steadily with age, so-called inflammaging. More radically, they looked at the gut bacteria of these twins to see if there was a link between their microbiome and their inflammation.

    There was.

    So what does this mean? What are the foods to eat or avoid? And at what age is it too late to make changes that can prolong your life?

    Today's guest is here to help us understand. Claire Steves is a professor at King's College London, a medical doctor, and the clinical director at TwinsUK. Claire's research focuses on better understanding how aging works and what we can do about it.

    Claire, thank you for joining me today. It's a real pleasure to have you on the podcast. Why don't we start like we almost always do with a quick-fire round of questions from our listeners, we have some very simple rules. You can say yes, you can say no, or if you have to, you can give us a one-sentence answer, but you're not allowed more than one sentence.

    And we know that all scientists find this really hard, so do your best. Are you ready to go?

    [00:02:01] Claire Steves: Yeah, go for it. 

    [00:02:02] Jonathan Wolf: So Claire, are most of us doomed to many years of poor quality of life before we die?

    [00:02:09] Claire Steves: No. 

    [00:02:10] Jonathan Wolf: Well, that's a very reassuring start. Once we are in our sixties or older, is there anything we can do that can really improve our long-term health?

    [00:02:20] Claire Steves: Yes. 

    [00:02:21] Jonathan Wolf: All right. See, it's going to be positive all the way today. Is it possible to reverse age-related poor health? 

    [00:02:27] Claire Steves: Ooh, interesting. Sometimes. Am I allowed that? 

    [00:02:32] Jonathan Wolf: Absolutely. You are, of course. In fact, that's where a lot of people go. Alright, another great question here. Can the microbiome influence age-related conditions such as dementia and Alzheimer's?

    [00:02:45] Claire Steves: Yes. Probably Though we haven't got all the evidence we need yet. 

    [00:02:49] Jonathan Wolf: What's the one thing that I should do to keep healthy in later life? 

    [00:02:54] Claire Steves: Wow, you make it difficult, Jonathan. One thing. Well, probably if I was going to do one thing, it's to keep as physically active as I can. 

    [00:03:03] Jonathan Wolf: And the last question I have is, does chronic inflammation earlier in our life play a role in aging?

    [00:03:10] Claire Steves: Yes, undoubtedly.

    [00:03:12] Jonathan Wolf: Brilliant, and I think we definitely want to get into all of those topics. Just before we do, I wanted to say what a pleasure it is to have you on the podcast. So many of our listeners will have used the ZOE COVID study during the pandemic, and what they may not realize is that Claire was absolutely critical, as we crazily put that together in the first few weeks because Claire with Tim basically figured out all the questions that we needed to ask people right at the very beginning before we understood anything really about COVID, about how we should try and understand what was happening with people's health and sort of their background health conditions. So, Claire, it is wonderful to have you on the show.

    [00:03:50] Claire Steves: It's great to be here, Johnathan. 

    [00:03:52] Jonathan Wolf: And I was just thinking actually, as I did that, that, of course, I was locked away, you know, in my house like so many people and you were actually out in these wards, and visiting people in residential homes who were very old and quite frail. And that at this point, basically, we had no idea whatsoever about what was going on or even what the disease was.

    And so you were sort of my picture into the frontline. 

    [00:04:16] Claire Steves: Well, that's right. I mean it was such a difficult time and we are still feeling it now actually. And right at the beginning of the pandemic, I was quite concerned about the lockdown, to be honest. And I remember saying to my husband, I'm not sure whether or not the pandemic, the illness itself or the effect of lockdown are going to be the greatest on aging overall.

    And certainly even patients I saw yesterday still saying that actually the social isolation and the inactivity that the lockdown brought for them really made a difference to them and their development over the last couple of years. And I think that's certainly true, but you are right, Jonathan, we were also obviously in settings where older people or frail people were getting COVID and we saw the range of different symptoms that people could get. And of course the sort of devastation that it brought on everybody within the care home sector at that time. They were so isolated from family members. 

    [00:05:13] Jonathan Wolf: And Claire, maybe we could just sort of start at the beginning. So what is aging, what's happening in our bodies as we age? Because this is your area of specialty, but it's slightly mysterious.

    I was thinking about this morning and it's one of these words. We all understand it, you know, you learn it as a small child, but what is it?

    [00:05:35] Claire Steves: So, interesting. When we look at almost any function, be it cellular or be it a sort of complex function like being able to walk or do specific tasks or even breathe out, in the lung function test, we see that over childhood to early adulthood, our performance improves. And then we get to about the forties and it sort of plateaus. Some features actually continue to grow. For example, your ability to use words and so on. Interesting. Maybe a measure of wisdom, but most things actually then start to plateau off.

    In terms of functional performance, the maximum function people can reach and then gradually decline. And actually how they change is very individually specific. So one person might actually reach that plateau later, decline less. Another person may reach an earlier decline quicker. Also, there's a bumpy road. It's not sort of uniform, how people change over time. So that's why actually what we see in populations is that individuals get more different from each other as they age. So there may be some 80-year-olds who are completely fit as a fiddle, able to really engage in every way that they used to when they were 40, and others that have lost their independence and are functionally dependent on others.

    [00:06:56] Jonathan Wolf: And Claire do all those different functions you have, do they tend to decline in the same way? Because, you know, I could think that maybe my physical health might deteriorate faster than my mental health or you know, I guess lots of people listening to this call are thinking what they're really scared about is the reverse, right? Physically, maybe that's okay, but their mental capability declines. Do these two tend to sit together or are they all sort of coming off this plateau you're describing, sort of getting worse than in your 40s? Are they all completely independent? 

    [00:07:27] Claire Steves: No, so very interesting. They don't change all the same, and they don't change the same in individuals. So in other words, some people may have a particular problem with their bone health that accelerates faster than their cognition and so on. And we've looked at what actually is similar across these different patterns, and we've seen that actually the genetic factors that are related to a change in aging over time are actually quite small, and they're very different between different organ systems.

    There are some environmental factors that really are shared between different organ systems. So in other words, there seem to be some things within our environment. We're using twin studies to pick this out, that drive organ aging across all systems, and also the environmental component to change over time is really important and that's why I've shifted the emphasis of my research onto trying to really unpick what are those environmental factors that we could change maybe and improve aging for older people. 

    [00:08:26] Jonathan Wolf: You are saying that one of the things that you do, and I guess this is through this massive UK twin study that you are the clinical lead on, is try and understand why people age and at different rates, and I think you're saying that actually, our genes turn out not to be as big a part of that as maybe you had thought?

    [00:08:45] Claire Steves: Yeah, that's right. So genes contribute quite strongly to that peak that each one of us can achieve, say in our forties, fifties, whatever. But it doesn't really contribute that much to how we change after that. 

    [00:08:58] Jonathan Wolf: So what you're saying is, you know, if I'm gonna be a great violinist or a great author, or just really strong in the gym, the genes are an important part of that, but then how much I maintain that or how much I deteriorate as I get older, it's no longer really about the genes. Is, is that right Claire? 

    [00:09:18] Claire Steves: That's right. 

    [00:09:19] Jonathan Wolf: I would say there are a lot of people on this call who have definitely hit their forties. You know some may be, you know, well past that. So they're all interested in, okay, so how do I maintain this? Good news, because your genes, you can't change. So what are the factors that are then influencing it?

    [00:09:36] Claire Steves: Yeah, so well, I guess the two biggest factors probably that we know about, and it's not so easy necessarily to change them. The first one is physical activity, physical fitness, doing stuff using your body, even standing up more, and being less sedentary. Actually, that's a really big driver and it's really interesting to me that it's not just a driver of physical health and bone health. It's also a driver of a healthy immune system, and it's also a driver of a healthy brain. 

    [00:10:04] Jonathan Wolf: Oh, that's amazing. So I think that's probably not what most of us are expecting. I think we all know that we should do more exercise, right? I think you'd have to be living under a rock, not to have heard this.

    [00:10:15] Claire Steves: Mm-hmm.

    [00:10:15] Jonathan Wolf: But I think generally we associate that with your physical ability. But you are saying it's not just that. It also affects things like your immune system, which you would think had nothing to do with whether or not you were being physically active. Is this something that has been known for a long time or is this more recent science?

    [00:10:33] Claire Steves: No, no. This is quite recent science actually. There are studies which have shown really in the last 10 years that actually a physical activity, really a sort of strong physical activity changes your immune system, makes it much more similar to younger people. A team had a look at the total body physiology and also the immune cells in the blood of people who did a lot of cycling very regularly.

    So they're very physically active, older adults. And they saw that their blood cells and their immune cells were similar in performance to very much younger people and very different from most sedentary old rattles. And they sort of came up with this idea that actually maybe. All the aging that we see around us is not necessarily because of aging, it's because of increasing physical inactivity, which then drives changes.

    And I think that's partly true, and it certainly seems to be that physical activity and physical fitness, it doesn't mean going to the gym and being sort of super sort of athletic about it necessarily. But it is a really good driver of health across the board. 

    [00:11:38] Jonathan Wolf: That's really interesting. And so beyond bone health and physical health and immune system, does physical activity affect anything else beyond that?

    [00:11:46] Claire Steves: Certainly, and this is what I saw within my Ph.D. when I was looking at cognitive aging. So I was looking at why some older adults, their cognitive function really changes very much, even though they don't necessarily have dementia. And over 10 years we saw that the strongest driver was actually physical performance right back at the beginning and that not only affected their cognitive performance on tests, but also you could see very clear differences in the brain structure and function of those individuals that performed more physical activity at the beginning than those that didn't.

    [00:12:18] Jonathan Wolf: That's, I think really exciting. I'd love to talk a bit more about it. One question that came up a lot actually from listeners that you haven't really touched on yet is about the microbiome. And you know, the question is, you know, what role, if any, does the microbiome, you know, these trillions of bacteria in our gut have on aging?

    [00:12:34] Claire Steves: Yeah, so very interesting. So as we develop through, you know, childhood, our microbiome shifts very significantly. As we change our diet, then it tends to sort of become our own personal microbiome that is actually different from other people's, but it stays stable and stays with you throughout your twenties, thirties, forties, and fifties.

    Then we see, a sort of like, as people start to age and start to become frail, there are changes that happen within the microbiome. And it was quite difficult to pick out actually at the beginning, whether or not that was because the body is changing and the host therefore us, yeah? Becomes slightly less of, a good place to live for these microbes.

    Or is it that actually there's an interaction where the microbes are also driving health and the answer is probably actually both? And we see now some new studies coming out there, intervention studies showing that actually, you can change the microbiome and that change is associated with health. 

    [00:13:33] Jonathan Wolf: And I think some of your own research on the twins has been looking at microbiome and aging. Is that right, Claire? 

    [00:13:39] Claire Steves: Yeah, that's right. So we were one of the first that sort of looked at that in the community population, the relationship between microbiome parameters of features in the microbiome, composition in the guts, this is in stool and the development of frailty, and we saw that even in sort of quite early stages, we could see differences.

    And actually, within twin pairs, we could see that frailer twins had a microbiome that was distinct from their sisters who were not frailed. So one of the things that we are really interested in trying to understand aging is to look at identical twins and non-identical twins as well, who share genetics, but they don't share lots of factors around an environment, and they actually don't share a lot of their gut microbiome.

    We see that the gut microbiome, on average, about 17% of the variation in the gut microbiome is down to genetic factors. So the majority is not down to genetic factors, it's down to environmental factors like diet. 

    [00:14:37] Jonathan Wolf: Which is amazing, isn't it? So you're saying there's only 17% of what you see in their microbiome is controlled by their genes. This is surprising, isn't it? Compared to what you would've expected when you thought about genes controlling us 20 years ago?

    [00:14:51] Claire Steves: Yeah, I mean, I'm not sure whether it's surprising. I mean, when I say 17%, there are some specific elements of the microbiome. They're a bit more heritable than that, and there are lots that are less heritable.

    So it's on average 17%. But the point is, is that actually, your genetic factors don't necessarily drive what's within you. That actually environmental factors and things that happen to you along the course of life are probably really important. And we know that from the early studies, looking at even mode of delivery, say, for example, individuals can change the microbiome, how many antibiotics they receive during life.

    All of these kinds of things, they're environmental factors. So it's not that surprising that genetics doesn't drive the microbiome very much. But it does go to show that, you know, we can't focus all our attention as we thought perhaps in 2000, on genetics to understand the disease. 

    [00:15:39] Jonathan Wolf: And so you were saying that as a result, you could have two identical twins who later on in life look quite different. Is this right, Claire? And then you were explaining about the microbiome differences. Could you just sort of bring us back to that? 

    [00:15:51] Claire Steves: Yeah, so I've been very interested in understanding using twins, why different people might age differently. And so we have within the cohort some individuals where one twin is slightly frailer or has a particular disease, whereas another twin is less frail or doesn't have that particular disease. And so we are looking at the biomarkers that we collect in them beforehand to see which ones can explain the difference in how they age. And indeed, we've found differences in the microbiome between individuals, and the specific groups of microbes that we found that were associated with being more robust, are also actually the exact same bugs that we see are associated with adherence to diets like the Mediterranean diet. So this is coming back to this sort of idea that the gut microbiome is shaped by the diets that we eat and that it is related to aging, but it's then taken sort of like some other intervention studies that we and others have done to show that actually, we can change some of these outcomes for individuals if we deliver microbiome interventions. So we've got a very exciting trial that we've not yet published, but is just going to be coming out sort of in the early in the spring, which basically shows this within a small number of individuals. And we need further larger studies to really show this. But I think it's really exciting. 

    [00:17:15] Jonathan Wolf: And what does a small study show, Claire? 

    [00:17:17] Claire Steves: So it shows that prebiotics that people have taken matched against a placebo that looks exactly identical, where we compare cognition within individuals taking the placebo or taking this prebiotic, we can see in just 12 weeks a difference in their outcomes in terms of their cognitive function.

    [00:17:35] Jonathan Wolf: That's amazing. So just to make sure I've got this, you're saying you are looking at all of these pairs of identical twins. They have the same genes, but actually, you're seeing, you know, one of them is ending up frailer, you said, than the other. You're then looking at their microbiome and you're seeing that they've got these very different bacteria. And then the question is, are the bacteria partly causing this or is it just as a result of the frailty? And I think you're saying it can work in both directions, but there's some really exciting evidence and you're talking about a new study you're about to publish that shows actually you can shift the microbiome and then see it actually affects the things that you look at in terms of aging and frailty and mental cognition. Is that right, Claire? 

    [00:18:16] Claire Steves: Yeah, that's right. And interesting that when we've done this, we've done it in the early stages of the development of the condition. And I think this is really important because some of the studies trying to affect the microbiome run in very late stages of frailty development. Found it much more difficult to change things.

    So I think if there's a message that comes from that, it is that we need to be acting and changing our aging early enough, yeah? It doesn't have to be right back in our twenties, but you know, we need to be thinking about things ahead of time and starting to change things sort of when we are 50, 60, 70 rather than waiting till we're really frail.

    [00:18:55] Jonathan Wolf: And I think, look, that's really interesting. I'm sure everybody listening is thinking, okay, so I'd like to make sure that I'm not frail. I want to make sure that I don't get dementia. You know, I'd like to be of high quality of life for as long as possible while knowing that I can't ultimately probably postpone death. What evidence is there to show that sort of aging and the chronic conditions that come with age can be avoided or slowed down rather than just it's going to happen and you are sort of locked into this? 

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    [00:19:23] Claire Steves: So that's interesting because of course there are some conditions where it's an either/or. It's a true binary, so you have it or you don't have it, yeah?

    And these we call diseases and they're what medical science has been really good at treating, diagnosing, and treating and, and that's one of the things that we've done well at in the 20th century, really. But there's another set of conditions that are more indolent and gradual, yeah? This is around sort of things like your muscle function, so the development of something called sarcopenia, so thin muscles and poor muscle function, which is much more subtle and really difficult to sort of say this is when it's happening. And those things that develop really gradually, those things potentially we can change the rate that they develop much more simply. So I think, it kind of depends on what sort of condition you're talking about.

    [00:20:10] Jonathan Wolf: Got it. But I think you were saying in a sense if we intervene earlier, so you don't wait till you're 80 and you're in a really bad way, if you intervene earlier, actually you can really make a change. Is that right, Claire? 

    [00:20:22] Claire Steves: Yeah, so I think what your question was saying was this saying, is it, are you just putting it off or can you change the development of it, overall?

    Yeah. So in some things, like for example, Alzheimer's is a good case in point. We know that there are some, for example, genetic factors that lead to an increased risk of Alzheimer's. But we also know that if someone has that genetic risk, they can very significantly delay things by taking care of physical activity, taking care of other conditions, making sure their blood pressure is controlled and their cholesterol is controlled and their vascular risk is controlled as well.

    So we know that we can really push the boundaries of something like that, which has a sort of fairly strong genetic component. Whereas other conditions like our ability to walk up the stairs, that's something where, you know, if we do it right, we could actually escape that problem completely. 

    [00:21:14] Jonathan Wolf: Got it. So you are saying there are some things that maybe it's a disease that ultimately we may not be able to avoid.

    And there are others you're saying that maybe actually we're always going to be able to have, you know, for example, the physical capability to walk up and down the stairs. There's actually no reason to think that you couldn't maintain that forever throughout your life. 

    [00:21:34] Claire Steves: That's the hope, yes.

    [00:21:36] Jonathan Wolf: Well, I like that. It sounds very positive. And you've talked about physical activity, you've touched a little bit on the microbiome. What are the other modifiable factors that, you know, there's evidence for that can really affect the rate at which we age, and, you know, whether there's poor health as we age?

    [00:21:58] Claire Steves: So I think the third thing that's really interesting, and there's a lot of growing evidence is around infections, yeah? And it's a really interesting and hot topic around COVID-19, for example. I mean, we've seen an illustration of how people who have had COVID-19, especially right early in the illness, had an increased risk of then going on to get cardiac events, diabetes diagnoses, and things like this.

    Even when you adjust for risk factors for COVID in the first place. What I think that does is that actually illustrate what happens in all infectious diseases actually. And when you look at something like influenza, you see the same things which are mainly short-term risks, but there isn't risk that goes on for several months after an infective episode. And so I think this is something that is very interesting and I think, you know, probably affects lots of aging systems and I certainly see within my patients that say, having recurrent urinary tract infections is something that really kind of adds and drives the development of conditions like dementia as well.

    [00:23:04] Jonathan Wolf: Got it. That makes sense. So, Claire, you've touched already like a couple of times on sort of Alzheimer's and dementia, and I'd love to talk a bit more about this and at a personal level, you know, it's something that's really touched my family as I suspect it has from many people who are listening.

    So my grandmother got Alzheimer's, she got it pretty early. She was in her sixties. It came on quite rapidly. You know, I think anyone who's experienced it, it's a horrible thing for everybody. Both, you know, for the person who's experiencing it to start with and then just for the whole family outside. And I know that you know, my father who is in his seventies now, I think this is like the thing he's most scared of actually. It's not dying. It's this idea that he will get Alzheimer's. He's incredibly mentally active, he's still working full-time, all of these things. And so I think that I also share some of this fear. It feels like one of the scariest things that might happen to one because you realize there's this big difference between, you know, the point that you die and actually you could have this whole period before where it's not only that it's terrible for you, but you can see, you know, the pressure on your family is so high.

    What does your research tell you, I guess, about whether there's anything we can do about, you know, Alzheimer's and dementia more broadly, maybe start to help us understand what's going on, perhaps, but then given that, is there anything we can do about it? 

    [00:24:28] Claire Steves: Yes, I share with you the anxiety about this, but also not so much anxiety, but you know, really wanting to try and do something both to help individuals that I see as my patients and also to try and do research to sort of underpin things a little bit and work out how we can change things.

    So dementia is an umbrella term where someone has, because of a cognitive change, a change in global cognitive function, is no longer able to carry out activities that are required for it to be independent, yeah? And that has to be going on for at least six months and it needs to be progressively changing. So that's the sort of clinical definition of dementia.

    But of course, there are multiple things that can cause that. And the three main causes of dementia in this country are Alzheimer's disease, vascular dementia, and Lewy body dementia and Alzheimer's disease, and Lewy body dementia share similarities. And they're to do with protein deposition within cells in the brain, which is then neurotoxic over time, and then they affect the brain cells and they tend to affect certain areas of the brain first.

    So in Alzheimer's, the area of the brain that's affected first is really the parahippocampus and hippocampus. These are areas that are recording systems for memories. And they're also interestingly involved in spatial location as well. And so the things that go first in Alzheimer's disease usually are the short-term memory.

    So you can't remember what was said five minutes ago or 10 minutes ago, but you can remember your past, you know your childhood really well, but the recording system is broken as it were, because of the areas of the brain that are affected first. And so we see within different dimensions, we see slightly different patterns.

    But the thing is that cognitive change happens quite a long time after the disease process is actually starting within the brain, okay? And so this is the problem, is that by the time you actually have those short-term memory loss problems, it could be that that's something that you perceive, which is actually more related to sort of anxieties and other pressures.

    But actually, if it is because of dementia, it's often been there for 7, 10, or 15 years. Now that's where this whole issue around what can we do to prevent it sort of comes because the proteins that are laid down in the brain, we don't know exactly why they're laid down. And there are some really interesting hypotheses that actually say that they might be laid down in response to bacteria.

    Actually, this area is not really understood, but this might explain partly why. Actually just busting and getting out those proteins doesn't seem to be the clear solution that people were hoping 10 years ago, it would be. So the question is, what can we do? Well, we know that systems in the brain already clear those proteins, okay?

    And those systems are immune cells, but they're also the system of flow around the brain that helps a brain to clean itself out. And that's helped very strongly by, you know, good sleep architecture. So it's one thing that we haven't talked about today is sleep and how actually sleep might be one of the things that we could do to help increase the ability of our brains to cope with these proteins that gradually develop over time.

    And then the immune system again, the real importance there of good dietary uptake. And then of course, we've got to support the brain in other ways to be as active as we can. And so making sure that our hearing and our vision are optimized actually early on is really important. So there's some new evidence coming out now that says that wearing a hearing aid actually prevents or at least delays the onset of dementia, yeah?

    [00:28:10] Jonathan Wolf: That's amazing. So you're saying that just being able to hear better-

    [00:28:14] Claire Steves: More inputs, the brain stimulates more. May affect how you present, but also actually helps your brain function. 

    [00:28:22] Jonathan Wolf: And so does that tie into, because I guess what you haven't mentioned there, or maybe you're just getting onto this, is this idea of your brain sort of being like a muscle and having to do stuff.

    So if it's like thinking it's struggling with something new, you know, it's interacting, is that real science or is that just like nonsense that people, you know, talk about on the internet? What does the real science tell us, Claire? 

    [00:28:44] Claire Steves: So it's really interesting because there's definitely evidence that doing cognitive tasks does work, can really improve the performance and change brain structure actually as well.

    Really interesting. But what's curious about it is, is that sort of like routine things that you might do on a computer or whatever tend to train certain areas and certain functions, but they don't necessarily have crossover onto other areas. And that's why I was really interested in the physical activity effect because physical fitness and performance seem to have effects on the whole brain. So it's something to do with cardiovascular, but also maybe hormones that produce by muscles as they're working and the immune effects that actually change the whole brain. But we talked at the beginning, didn't we? About social isolation, yeah? 

    And being socially active and being engaged with your community, these are things that pull on loads of different tasks of your brain, yeah? So that is really good, you know, full body workout as it were, just being socially active and that's probably what underpins why social activity is so important to maintain a healthy brain.

    [00:29:45] Jonathan Wolf: Let me ask a bit more about that actually because that's interesting. I'd assumed that the social activity was important because of this sense of emotional bonding and warmth. You know, I'm somebody- I get really miserable, Claire if I'm on my own. You know, I'm not really well set up for home working because I like people around me.

    You know, as soon as my wife comes home or my kids are home, I'm like really happy. Like I'm always wanting a hug. I'm needy like a puppy dog or something like that. And so I think about social interaction, I guess, as being like I need that warmth. But it sounds like you're talking about something a bit different, which is, well, you're having a conversation with somebody and it's making your brain have to work.

    Is it actually that second part that is really important to sort of keep us healthier for longer? 

    [00:30:27] Claire Steves: Oh, well, fascinating question. I'm not sure how I would design a study to really unpick the two of those, but- 

    [00:30:33] Jonathan Wolf: There isn't a big research study that explains the difference between these two?

    [00:30:37] Claire Steves: Yeah, interesting. There probably are attempts to try and do that, but I think it's actually, I mean, the number of the matter is it's probably both, isn't it? For a starter, why are we here if we can't enjoy each other and contribute to the enjoyment of others? But yeah, no, I think there are things, otherwise social activity is actually very cognitively taxing. That's why we've developed such a big brain, which is to be socially interactive. 

    [00:31:02] Jonathan Wolf: This is ZOE Science & Nutrition. So although you touched a little bit in places on diet, I'll have a lot of complaints if we don't talk a bit more specifically about diet and how this ties into this conversation around sort of dementia more broadly. Is there any evidence around diet is linked to this? 

    [00:31:22] Claire Steves: Absolutely. Yeah. So there are quite a lot of longitudinal studies that show that increasing fruit and vegetable consumption can improve cognitive function. Fewer studies really show that very convincingly with dementia. And few studies show that it's quite difficult to do, except for ZOE, and really big. Intervention studies for long enough can show changes in outcomes like dementia. But there are observational studies for example, the twin study, but there are others all around the world actually, that show the quality of fruit and vegetables is associated with reduced risk of dementia and cognitive impairment later in life.

    And also potentially, You know, reducing red meats and animal sources of food and actually changing more to a plant-based diet. Early research coming out showing that that's probably beneficial for cognitive aging. 

    [00:32:16] Jonathan Wolf: Got it. And I know this is one of the areas that you are involved with us, in fact, in the ZOE Health study because I think we're fascinated to understand more about what might impact dementia.

    And I think there are lots of hypotheses, right? That improved diet quality, improved microbiome health, these things might really impact it and as everywhere, right? The quality of nutritional research has been limited by just the small scale of the studies and maybe the limited quality of the data and the fact that it's very challenging to follow what people eat over many years.

    [00:32:48] Claire Steves: Yeah, so it is such a challenging area to research. Actually, one of the reasons why it's so challenging is because actually, diets are very different in different groups, and of course, diets that are really good for you, that have lots of fruit and vegetables require a certain sort of educational background to really create them.

    And also they do require some cost change, you know. It is cheaper still probably to have white bread, white rice, sort of low-vegetable diet. And that's one of the issues is that many of the studies have found it difficult to unpick these relationships between social factors, which drive, for example, poverty, which drives a lot of risk of disease and diet.

    But I think we could turn that all around its head as well to say that actually diet is something that probably explains a lot of social inequalities, in health outcomes, what we need to do is do large enough studies that are really powered and are randomized, proper randomized control trials to really get away from that possible confounding.

    [00:33:55] Jonathan Wolf: I think that's right and it's obviously particularly bad in countries like the US and the UK where we do see this massive difference and you know, a huge amount of ultra-processed food. And I think if we were having this conversation in Italy, people would be less convinced by what you just said.

    They'd be like, well, of course, they have poverty in just the same way but actually just in general, far lower levels of ultra-processed food and a lot more people cooking food, even if their income is very low. That is just much more based on, you know, whole foods. That is not to diminish the problem, which is a huge problem whether you're anywhere in the developed world, but I guess it suggests it's not impossible to imagine that you might be able to improve it because I think this is not, you know, as not as true across all rich countries. And again, if you go into Asia, you again see this difference. So in part, it feels like we've got ourselves into this. 

    [00:34:49] Claire Steves: Absolutely. And overall a plant-based diet is what is consumed by the majority of the world that have a lot less income than in Western countries. So it is completely not impossible to change our diet to be much more potentially healthy for a whole range of diseases, including potential dementia.

    But the wherewithal to do that is quite challenging within our current Western environment. The pressures are not balanced in a way, which is going to promote equality of access. So that's something that I think we've just got to do work on actually as a scientific community as well as a nation.

    [00:35:26] Jonathan Wolf: Amazing. I also had a bunch of questions about menopause. And Claire, I'd love to understand what we know at the moment about how menopause might play into aging in these age-related risks. 

    [00:35:39] Claire Steves: Fascinating. Well, I wonder whether some of your listeners might be really interested to think about why we have menopause and the fact that, for example, we are one of the very, very few organisms that have a menopause.

    And so the other organisms as far as I remember are groups of whales, killer whales, and pilot whales, you know, that have menopause. But for example, dogs, don't have menopause. Horses, whatever. They don't, and scientists have thought of, thought for a long time why that might be the case. And actually back in the sixties, this hypothesis, the grandmother hypothesis was developed.

    It says that actually, the reason why women have menopause is that in order for our offspring to succeed is actually highly beneficial for women to not have kids at the same time as their kids. Basically, or at least have some space. There's some space that happens. So basically the whole reason behind menopause is so that women can be functionally helpful to their daughters who are child-rearing.

    And so it's meant to be a functional thing. Yeah, it's a really functional thing, but the fact is that in that process of going through menopause, there are significant changes that happen to a woman, which then, you know, affect her at that time. But hopefully, once she gets through that actually she can be very functionally active and so on. So it's not so much related to aging. I think we've got to think of it as a developmental phase, which is actually useful and functional. It's not there for no reason. It's very specifically there in humans and, we should make the most of it. But that does not say that there are certain challenges that happen as women go through menopause. The usual average age is about 50, which just like any sort of developmental phase, just like adolescents, takes some adjusting to. And has some implications for aging later on. 

    [00:37:28] Jonathan Wolf: Got it. Thank you, Claire. Well look, at this point, I think we would love as always, to try and pull this together into sort of actionable advice for our listeners.

    And, you know, I think what they're always hoping for is sort of what are your top tips to help us age and stay healthy? So having listened to this, you know, I think we're all taking away this view that there's a lot that you can do. If you were advising them, you know, right now on the things that they should think about doing in order to, you know, maximize those healthy years, what would you be saying?

    [00:38:00] Claire Steves: So I think number one, as we said, keeping physically active doesn't mean going to the gym. It means doing those steps. I'm a great believer in sort of step counters, but also, just doing one-third more than you did before. That's the first thing. The second thing is about diets. Sort of like really trying to change diets to more high-fiber and plant-based sort of sources of proteins. Probably the best evidence for aging overall. And then the third thing is around making sure that our sensory systems are at the tip-top. So making sure that we get hearing aids and visual aids that really help us sort of really interact with life so that we can keep that social interaction driving forwards. If I'm allowed another, am I allowed another one? One more?

    [00:38:48] Jonathan Wolf: You could have as many as you want, Claire. I think our listeners are just, you know, they'll be writing it down right now. 

    [00:38:53] Claire Steves: We talked about social activity and that's why sensory sort of things are really very important, but the other thing is sleep. Investing in good quality sleep is probably very important for aging, not just dementia and Alzheimer's, but also other sources of aging. 

    [00:39:11] Jonathan Wolf: I think that sounds brilliant. And so Claire, I think the last question, because we had this and I just love the question. And now we go to sort of towards the end here. What's the biggest myth about aging that you commonly hear?

    [00:39:24] Claire Steves: Well, I think it's this thing. It's all wear and tear. It's inevitable. All of us know it's not inevitable by looking around us at the differences between people of the same age, yeah? Now the differences aren't actually driven very much by genetics. The differences are driven mostly by environmental factors. So find that really robust, amazing person that you know, and ask them what they do and try and mirror that. 

    [00:39:52] Jonathan Wolf: Well, for me that's Tim Spector. I don't know about you Claire, but you know, Tim is basically like this walking advertisement for how we would all like to be. I won't say his age, I'll get in trouble but he's a bit older than both of us and it's pretty impressive.

    Of course, the only thing is he's never allowed to tell anyone when he does have a cold, and I'll let you all into a secret, which is even Tim does still get colds, but you know, it breaks this idea of him being basically Superman and he's pretty close. I mean, he's in fantastic shape.

    And what's interesting is he's clearly following all of the things that you describe Claire with a very big focus, obviously on the diet and the health of the diet, but very physically active as well, very engaged, you know, in terms of the cognition and everything you're talking about. So that's really interesting.

    I mean, the other thing I think about is my parents who are both working, so apparently being a workaholic then is potentially good for long life, which seems like the exact opposite of what, you know, I was taught as a child, you know, the overwork kills you. I'm pretty sure that there is sort of that idea, but maybe I'm taking away from this, that overwork is just fine.

    [00:41:01] Claire Steves: Well, interesting. I suppose it does depend on whether or not it really stresses you out and whether it gives you enough sleep. If you're a workaholic and you are loving it and you're getting enough sleep and you're not too stressed, then that's probably ideal. 

    [00:41:12] Jonathan Wolf: That's really interesting. They used to talk about this, you know, like the stress would kill you and give you heart attacks, right? In the sixties, right? This is all the story, but I think we've now decided this was mainly the diet, isn't it? Or alcohol or smoking. Probably the smoking. I'm thinking about that sort of whole Mad Men idea. More than just working is what causes you stress, per se. It's, as you said, it's maybe unhappy working. What do think? 

    [00:41:36] Claire Steves: Yeah, that's interesting. But you see what was driving the diet, what was driving the alcohol, what was driving the smoking? Could it be the other way round actually that yes, those things were really important? But then a common driver is stress. And I think, you know, we see that in stressed animal studies. We see that in social inequalities. I think stress is still a big factor, but it acts through these other things and it's not something that we can't necessarily try and change for us and for other people. 

    [00:42:02] Jonathan Wolf: Got it. So what you're saying is, you know, if the work is driving stress, actually, this is pretty bad.

    If the work is actually maybe part of what you're enjoying and giving you purpose in life, it could actually be very beneficial. 

    [00:42:13] Claire Steves: Absolutely. 

    [00:42:15] Jonathan Wolf: Brilliant. Claire, thank you so much. I really enjoyed that. It's such fun to have you on the podcast. I'm going to try and do a little summing up of what we covered and we've gone in a lot of places, so I'm going to do my best and, and please correct me if I've got it wrong.

    So, firstly we said that aging is this sort of natural process where most of our abilities are getting better until maybe our forties for many of us it plateaus, and then it declines at very different rates for different people. You had interestingly, a huge focus on physical exercise, much more than I was expecting.

    I think you then talked about dementia. This is this disease that starts a long time before the symptoms. So again, there, you know, you can't just wait till you've got it, you've got to think about it. Interestingly, you then lay it on sleep. Talked a lot about diet and then I thought the last thing that I really hadn't heard before was fascinating is you can't expect your brain to work well if you can't hear properly, if you can't see properly, if you're not interacting with other human beings, and I think a very positive sign, right? Very positive message, you really can push out aging a lot further. Is that fair? 

    [00:43:22] Claire Steves: That's very good. I'm amazed, Jonathan, you've managed to summarize it extremely well. 

    [00:43:26] Jonathan Wolf: My wife has been telling me I should really get my hearing tested for the last two years, and I've been ignoring her because I'm like, I don't really want to admit I might be getting older, but now I'm like, okay, apparently it's going to affect my health. I'm looking into it straight after this podcast. 

    [00:43:40] Claire Steves: Fantastic.

    [00:43:41] Jonathan Wolf: Claire is such a pleasure. Thank you so much, and we look forward to having you back again in the future.

    [00:43:45] Claire Steves: Thank you very much, Jonathan. Been great to talk to you. 

    [00:43:48] Jonathan Wolf: It's a pleasure. Bye-bye.

    Thank you, Claire, for joining me on ZOE Science & Nutrition today.

    If, based on today's conversation, you are worrying about aging and wondering how to eat the best foods for your body, then you may want to try ZOE's personalized nutrition. Your ZOE membership gives you meal and recipe recommendations and scientifically backed nutrition advice on how to eat for your best health so that you can feel more energetic, improve your gut health, and reduce the risk of long-term disease.

    Your personalized nutrition program is based on our scientific research and the results of your personal at-home test. If you're interested in learning more about ZOE, you can head to joinZOE.com/podcast, and get 10% off your purchase. If you enjoyed today's episode, please be sure to subscribe and leave us a review, as we love reading your feedback.

    If this episode left you with questions, please set them in on Instagram or Facebook, and we will try to answer them in a future episode.

    As always, I'm your host, Jonathan Wolf. ZOE Science & Nutrition is produced by Fascinate Productions with support from Sharon Feder, Yella Hewings-Martin, and Alex Jones here at ZOE.

    See you next time.

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