Updated 10th April 2024

Dementia: Prevention, genetics, new treatments

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Almost 7 million people in the U.S. and 1 million people in the U.K. are currently living with dementia.

In this week’s episode, we’re joined by Claire Steves, a professor of aging and health at King’s College London. She’s also a consultant geriatrician at Guy’s and St Thomas’ NHS Foundation Trust and has been a ZOE advisor for many years.

Claire explains how to recognize the early signs of dementia — and how to reduce your risk. 

What is dementia?

The brain naturally changes as we age, and our cognitive abilities tend to decline. This is considered a normal part of aging. Dementia isn’t.

Dementia is not inevitable as we get older. It’s an umbrella term for health conditions that affect thinking and learning. These conditions cause changes that interfere with daily life and worsen over time.

The most common form is Alzheimer’s, and it has a very gradual progression. Physically, people with Alzheimer’s are often generally well. But they might ask the same question repeatedly or forget something that happened 5 minutes earlier.

Not everyone with short-term memory problems has dementia, but if this is a consistent concern, it might be worth getting checked out.

What causes dementia?

Most forms are associated with an abnormal protein buildup inside or between brain cells. This buildup causes the cells to die off. 

We don’t know exactly why it happens, but genetic and environmental factors are involved. 

What are the risk factors?

Genetics play a part in dementia risk, especially in early onset dementia, which starts in a person’s 50s or 60s. 

But even if someone is genetically susceptible to dementia, it’s not inevitable. This is because our genes interact with our environment.

ApoE is the most well-studied genetic risk factor for Alzheimer’s. We all have two versions of this gene. A variant called ApoE4 is associated with a greater risk. 

Around 25% of people have one copy of ApoE4, and only a small number have two copies. This gives a person an eight times greater risk of dementia. But it still isn’t inevitable.

We don’t know why ApoE4 increases dementia risk. But the reason seems linked to how our brain cells use fats. This may be influenced by our diets and perhaps the medications we take.

The importance of cognitive reserve 

Cognitive reserve is the capacity of your brain to improvise and overcome challenges. It’s an important factor in dementia risk. 

If we have high levels of cognitive reserve, we can delay the point at which we no longer function in day-to-day life. As Claire puts it, “We have further to fall.” 

So, even if the brain is declining, having more reserve to tap into keeps cognitive decline from affecting our daily life.

Building cognitive reserve begins in the womb. But if we’re exposed to tobacco or alcohol, or we don’t get the right nutrition, our reserve may be reduced later in life.

Childhood is also a crucial time for building up this reserve. Good mental health, social stimulation, and physical fitness all play a part. 

New medications

After a 20-year wait, new dementia drugs are becoming available in some places. 

These antibody-based medicines stick to proteins in brain cells and remove them. Although the benefits for cognition are still quite limited, these drugs do slow the progression of dementia.

But there are issues. For instance, removing the proteins from cells increases the risk of brain swelling, which can cause brain bleeds. So, people who take these drugs need regular brain scans. 

Currently, the balance between risk and benefit is unclear, so these drugs aren’t approved in the U.K. yet, though they are in the U.S.

Because these drugs are new, we don’t know how many years of good health they might provide. 

Overall, it’s still a huge leap forward. Now that scientists know how to remove proteins from brain cells, they can tweak these drugs to improve their safety and effectiveness.

How can you reduce your risk?

Several lifestyle changes can support your brain health and build up your cognitive reserve.

The power of food

“It’s about getting as many different-coloured fruits and vegetables into your diet as possible and making sure you're getting good, plant-based fats,” Claire explains.

Sources these fats include nuts, seeds, and olive oil.

“Because the brain is hugely metabolically active, it needs a lot of nutrients, and we know that a wide variety of plant-based nutrients is really important for brain health.”

Compounds called flavonoids from colorful plants are vital for brain development. 

Flavonoids feed your gut bacteria. So, they might protect your brain health through changes in the gut microbiome. The gut and brain are tightly linked through the so-called gut-brain axis

We also know there’s a relationship between blood vessel health and brain health. So, a diet that’s good for your heart and blood vessels is also good for your brain.

Why physical activity matters

Physical activity is vital. If you’re not currently very active, “Get out and walk for 45 minutes at least three times a week.” It will really make a difference, Claire explains.

Look after your teeth

About 35% of older adults have gum disease, and there’s a close relationship between oral health and brain health

Stay social and keep your brain busy

Although brain training games and puzzles might help, you might only get better at those particular games. To build up cognitive reserve, you need variety.

One of the most complicated things we do with our brain is interact socially — it’s much more taxing than a crossword puzzle.

Some physical activity can be mentally taxing, too, like cycling in London or dancing. So, choosing something that exercises your mind and body at the same time could be very beneficial.

The bottom line

While you can’t change your genes, you can influence a range of other important factors in your dementia risk. 

If you eat a diverse range of colorful plants, stay active, visit your dentist regularly, and interact socially, you’ll significantly reduce your risk of dementia.

Show notes

How soon should we start taking our dementia risk seriously?

In today’s episode of ZOE Science & Nutrition, Jonathan is joined by Prof. Claire Steves to explore the multifaceted world of dementia.

Claire and Jonathan delve into the significance of dental health, genetics, diet, and physical activity — plus, they unpack the latest research — to give you practical strategies for preventing dementia.

Claire is a consultant physician in geriatric medicine at Guy's and St Thomas' NHS Foundation Trust. She’s also a senior clinical lecturer at King's College London and deputy clinical director of the institution’s Department of Twin Research and Genetic Epidemiology. In the cohort, Claire leads research on the characterization of physical and mental aging traits and frailty.

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

Follow ZOE on Instagram.

Related to today’s episode:

Find our top 10 tips for healthier living: Download our FREE guide.

Are you interested in a specific aspect of dementia? Email us at podcast@joinzoe.com, and we’ll do our best to cover it.

Episode transcripts are available here.

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.

Today we're discussing a topic that's close to my own heart, and as many of us know all too well, impacts millions of families around the world. And that topic is dementia. Nearly 7 million people in the U.S. and almost 1 million in the U.K. live with a form of dementia, like Alzheimer's disease, and these numbers are a concern for many of us.

But today we're not just discussing challenges, we'll learn what steps to take to help prevent dementia. We'll also hear how to recognize the early signs and we'll find out if promising new Alzheimer's drugs are worth the hype. 

I'm delighted to have dementia expert Prof. Claire Steves back on the podcast. Claire is a medical doctor, a professor of aging and health, and head of the Department of Twin Research and Genetic Epidemiology at King's College London. She's also been a frequent advisor to ZOE for many years now. 

Claire, thank you for joining me again today. 

[00:01:14] Claire Steves: Thank you very much for having me. 

[00:01:15] Jonathan Wolf: Now you may remember that we always like to start with a quick-fire round of questions.

And Claire looks suddenly shocked because she's clearly forgotten about this, which we carefully designed to make professors deeply uncomfortable. And just to remind you, the rules are; you can say yes or no, or if you absolutely have to, you can have a sentence to answer. Are you willing to give it a go?

[00:01:35] Claire Steves: Yeah, I'll give it a go. 

[00:01:36] Jonathan Wolf: So. Is the brain the most complex structure in the known universe? 

[00:01:42] Claire Steves: Yes, it is. 

[00:01:43] Jonathan Wolf: That's pretty cool. Is dementia inevitable as part of the aging process? 

[00:01:49] Claire Steves: No. 

[00:01:50] Jonathan Wolf: Are women more likely to get dementia than men? 

[00:01:53] Claire Steves: Yes. 

[00:01:54] Jonathan Wolf: If my parents have dementia, am I certain to get it as well?

[00:01:57] Claire Steves: No. There are a bunch of new Alzheimer's drugs.

[00:01:15] Jonathan Wolf: Are they going to stop the disease for most people? 

[00:02:02] Claire Steves: No.

[00:02:03] Jonathan Wolf: If I change what I eat, can I lower my risk of dementia? 

[00:02:07] Claire Steves: Yes. 

[00:02:08] Jonathan Wolf: And finally, what's the most common misconception you often hear about dementia? 

[00:02:13] Claire Steves: That there's nothing you can do about it. 

[00:02:14] Jonathan Wolf: And that isn't true? 

[00:02:15] Claire Steves: That isn't true, no. That isn't true if you have it, and that isn't true about preventing it from happening.

[00:02:21] Jonathan Wolf: Well that's a wonderfully positive place actually I think to start this conversation. And this is a topic that's very close to my own heart. I think like a lot of our listeners who've listened to the podcast very regularly will know that my grandmother got Alzheimer's, it's an awful experience for the whole family.

You know, it was awful for me, but particularly awful for my father. And not just during the period when my grandmother got this and got very sick and actually died quite fast. Basically ever since that, my father has lived under the shadow, this fear that he was going to get Alzheimer's and he's actually a lot older now than my grandmother was when she got this.

But I think even now he feels like he doesn't ever know is he just going to have another six months or 12 months of his brain working? And I think it's had this profound impact on him. So I think I've definitely seen this firsthand and it's always struck me as one of the diseases that I'm most scared of having. Partly for the effect of myself and partly for the way that it would affect my family and the way that my family ends up thinking about it. 

It's a topic that's close to my heart is a way of saying this. I'm really excited to talk about it, but also very excited that you sort of started there by saying there's some things you can do. Because I think I always assumed there was nothing you could do about this. This was something that just came externally somehow as, you know, a roll of the dice, a stroke of fate.

And so, I'd love to make sure we really get into today about how we can lower our risk. But I'd love to start right at the beginning. Claire, could you just explain, like, what exactly is dementia? 

[00:03:57] Claire Steves: So dementia is actually an umbrella term. So lots of different things actually fit into that term of dementia.

But if we want to sort of classify it, it's a condition that involves cognitive function, so thinking and learning and memory. More than one domain of it, which is altered in somebody. That that's altered to such a degree that it then causes a problem in day to day living and that it's gradually progressive over time and needs to have been around for longer than a six-month period at the very least.

And actually, most people who get diagnosed with dementia have probably had some symptoms going back for, you know, maybe years. Unlike your grandmother, maybe, who sounds like it was more rapid progression. 

[00:04:39] Jonathan Wolf: And how is that what you're describing different from normal aging? Because I think many people listening to this will say, I think, again, this is how I was brought up. And I know this is now more contentious. I was brought up with this idea that well, when you just start to get old, then you fall apart, your body falls apart, your brain falls apart. So this is just literally the normal process of aging. 

[00:05:01] Claire Steves: So there are changes that happen with age in most people, you know, which we might call normal aging. And the typical things are, for example, the brain looks different when you look at it. There's some atrophy in older people. 

[00:05:13] Jonathan Wolf: Which doesn't sound good. Nobody likes the word atrophy. The older I get, the less excited I get about this idea of age. My body or my brain atrophy. 

[00:05:20] Claire Steves: So there is that, but of course, some of that might not be so detrimental. Then also there's some changes in processing speed in older adults, generally. So the speed at which things happen. 

[00:05:32] Jonathan Wolf: And when you say processing speed. 

[00:05:34] Claire Steves: So the ability for the brain to get through a problem or execute an action. 

[00:05:39] Jonathan Wolf: So this is like, do the crossword, or what do you mean when you're.. 

[00:05:44] Claire Steves: More simple than that really but basically any task you're looking at the time it takes to do that task. One of the simplest is a reaction time task. Say for example you're given a stimulus and you have to say when you see it. Or a choice reaction time when you have to press one button when one stimulus comes and another button when another stimulus comes. 

Those are relatively simple tasks, which measure the speed of processing. 

[00:06:04] Jonathan Wolf: So I'm thinking a bit like whack a mole. Is this what you're saying? Like something comes up and you're hitting it on the head. Is that what you're saying? 

And as we get older, we get worse at this. My son already feels that I've got slow reaction speeds, so I don't want to know what I'll be like when I'm 80. 

[00:06:17] Claire Steves: So this is really important and it's really important that sort of aging. Because that's why some older people when they fall or younger, older people, they would fracture their wrist, whereas older, older people might fracture their hip because they've got time to put out the hand.

[00:06:31] Jonathan Wolf: So what you're saying is that as you get older, things like just being able to protect yourself when you fall over by responding is slowing down. And that's your brain, which is slowing down.

[00:06:40] Claire Steves: Your brain is slowing down in normal aging. And I think that's something that we definitely see. Then there are dementias, which are really quite different from that. Where there's progressive decline in other functions, and different dementias have different constellations of symptoms, but we don't always get it completely right. Sometimes, actually, what's going on in the brain is not necessarily fully reflected in how people present. 

[00:07:02] Jonathan Wolf: And just before we get into that, I just want to make sure I'm, this sort of difference between normal aging, if you like, and not. I think you're saying it is normal to sort of slow down a bit in terms of the speed with which you respond. You can see changes. It sounds like you're saying almost if you're imaging the brain or something, you see this.

But it's not normal for you to not be able to think and interact and all the rest. And where I'm getting this is, you know, I think everyone listening to this can think of people that they know, relatives or friends who are very old, who are. incredibly sharp, exactly the same as they were many decades before.

Is that what you would think of as typically normal? Or is it the reverse, which is that they are the exception and your normal expectation should be that you sort of lose your core personality and capability as you reach old age? 

[00:07:52] Claire Steves: Really interesting questions. I mean, if somebody is changing in their function and in particular losing the ability to keep hold of, for example, short-term memory issues, then that's a warning sign. The other thing that's a warning sign is if they're not able to function in normal activities of daily life. 

So one of the first things that might be affected might be say, ability to manage finances or medication. So if someone else has to come in and take over because things are going a bit wrong, those are the sort of like early warning signs for most types of dementia. 

[00:08:22] Jonathan Wolf: And that's because you wouldn't consider that just the inevitable normal part of aging. You're saying that actually, and I'm just, and the reason I'm asking this again is because I feel that that's a bit of a shift from how I was brought up. Because you're saying, I guess, quite a positive thing I think Claire, right? That actually the normal expectation of aging is you can still manage your medication and your finances and your short-term memory should still exist.

[00:08:46] Claire Steves: Exactly. Exactly. 

[00:08:47] Jonathan Wolf: So tell us a bit about what happens with dementia. Why is it that this isn't the case for some people? Why is it that this is this thing that so many people, you know, are worried may happen to them?

[00:08:56] Claire Steves: The most common presentation and the most common cause of dementia is Alzheimer's disease. And Alzheimer's disease characteristically presents with a very gradual progression. And generally, the person is physically relatively well and their gait, for example, their ability to, you know, their walking is not too slow and it's not too altered. And yet they ask maybe repeated questions. 

They maybe don't catch hold of a full conversation. So they might ask the same question again, or you might realize that actually, you said something five minutes ago and they don't recall it. So that early laying down of that episode, in a sense, a tape recorder for short-term items just isn't functioning very well.

[00:09:36] Jonathan Wolf: So this is when you were mentioning short-term memory is taking over. This is like remembering things just in the last few minutes rather than something that maybe happened to you 50 years ago. 

[00:09:45] Claire Steves: Yep. And of course, be careful because not everybody with short-term memory loss has dementia. Sometimes when the brain is really working on lots of other tasks in, you know, maybe in the subconscious, whatever, maybe there's a stressor or there's something else happened, then obviously short-term memory can be affected.

So it doesn't necessarily hold that short-term memory loss is early Alzheimer's disease. But it certainly, if it's sort of like there and consistently there, definitely that's a sort of signal to say, we ought to get this checked out, see what's happening.

[00:10:10] Jonathan Wolf: What's going on? Why is this happening? 

[00:10:14] Claire Steves: Most of the common dementias that are really brain-focused, as it were, are because of neurons dying, basically, in certain areas of the brain, in particular.

[00:10:23] Jonathan Wolf:  And what are neurons? 

[00:10:24] Claire Steves: Neurons are the nerve cells. They're dying, probably, from a combination of factors in our genes and factors in our environment that contribute to that. And what we see… 

[00:10:36] Jonathan Wolf: And so they're dying a lot more in these people than they would be doing in an equivalent person the same age who is not having these dementia issues.

[00:10:44] Claire Steves: Exactly. And one of the things we see when we look at those cells under the microscope, is we see inclusions of certain proteins. So certain proteins have aggregated together and either inside the cell or outside the cell. So there's something going wrong. And that's not normal. 

This is one of the big conundrums of dementia is why that happens, why some people are more resilient to those protein depositions in the brain and have relatively, you know, high degree of changes in the brain, but that's not necessarily translating into how they present.

[00:11:15] Jonathan Wolf: And so just to make sure I've got this, you're saying that there are these proteins sort of forming these clumps in these nerve cells in the brain, that that seems to be very related to whether or not you get Alzheimer's dementia in general or Alzheimer's specifically.

[00:11:31] Claire Steves: So, Alzheimer's specifically has certain types of protein inclusions, and other more rare forms of dementia, rarer forms of dementia, have different sorts of protein inclusions. But ultimately, a lot of these neurodegenerative diseases that we call, you know, neurodegenerative types of dementia, they have protein depositions within the brain. In different parts of the brain, different patterns, different exact proteins as well. 

[00:11:53] Jonathan Wolf: But basically, there's a lot of stuff that isn't in your brain when you're 21 years old that is later. And there's a real link. 

[00:11:59] Claire Steves: There’s a relationship, but it's not a completely 100%.

[00:12:02] Jonathan Wolf: Complicated. Like I think one of the things I've learned on this podcast is that most things are. So it's interesting. When I hear that, I naturally think about these analogies that a lot of guests have talked about with cardiovascular disease and things being sort of laid down in your arteries, you know, mainly based on poor diet over decades building up and eventually that leading to like these pipes being blocked or something breaking free and into the heart.

Is that a terrible analogy or is there something, is there some similarity with what you're describing with things sort of, you know, ending up being laid down in our brain that are not being cleared away or…? 

[00:12:39] Claire Steves: Well, so yes, I think that's really interesting. Yes, the clearing away bit is absolutely the case. The difference in a way between the vascular, you know, cardiovascular disease, as you mentioned, is that the focus is really on the arteries and the blood vessel lining. 

Whereas in dementias, the focus is on the actual neuron cells and the cells beside the neurons that help keep them healthy. So the microglia or the other cells that are around supporting those neurons to function. 

[00:13:05] Jonathan Wolf: Is everyone having these proteins laid down in their brain, but normally we're unable to clear them away? Do we understand, I guess, what's going on here and therefore does that help us to understand, as we're going to start to talk more about what we might do. Why the things that help, do help.

[00:13:21] Claire Steves: You know, our cells are very complex organisms or, you know, complex structures that are constantly rebuilding the structures within the cells, but also things in ways in which they communicate outside that cell. So what's happening when you get these proteins deposited is that there's a problem with the clearance or either the manufacture or the clearance of those proteins.

[00:13:43] Jonathan Wolf: We had a really interesting podcast with a professor called Matt Walker talking about sleep quite a long time ago. And I remember one of the things that he'd talked about was this idea that when you sleep, you know, again, I was brought up to think that nothing happened when you slept. You just had to sleep for some reason.

And he was saying, no, actually, we now know your brain's very active. One of the things that's going on is somehow a sort of clear-up of your brain. Is that in any way related to this or…

[00:14:08] Claire Steves: Yeah I think there is, yeah. There is evidence that the clearance of protein also just simply the way that the fluid system around the brain, the CSF, the cerebral spinal fluid, the way that flows around the brain is affected by sleep. And then probably there's something that's happening much more deep within this, in the brain tissue, which affects the clearance of these proteins. So I think there is a relationship with, between sleep.

[00:14:30] Jonathan Wolf: I would love to shift maybe to one step away from the detail of what's going into the brain and more about. People listening to this trying to understand, okay, what are my risks? So are some people more at risk of dementia than others? 

[00:14:43] Claire Steves: That's true. And we know that genetic factors are important in the development of dementia and they're most important in the early onset dementias. So people who have developed dementia in their fifties or sixties, there's some stronger genetic influences on those. It doesn't mean that they're definitely going to be.

[00:15:02] Jonathan Wolf: I was going to say, does that mean that if I have bad genes, I'm doomed to get dementia? 

[00:15:06] Claire Steves: No, no, it doesn't. And of course, there's an interaction between those genes and the environment, which might be very important. 

So one of the most talked about, because it's actually really important gene is APOE, of which all of us have two. There's an APOE e4 is associated with increased risk of dementia. And so if you have two of those, you're actually much greater risk of having dementia. It doesn't mean it's definite. 

[00:15:28] Jonathan Wolf: And how bad, like, just to help us understand, like, if you have these two, what do you call them, e4 genes? 

[00:15:36] Claire Steves: It's about eight times greater risk.

[00:15:37] Jonathan Wolf: Okay, so that sounds pretty bad. And how many people will have two of these? 

[00:15:42] Claire Steves: Oh, not very many. So I think it's, you see, about 25% of the population have one. 

[00:15:44] Jonathan Wolf: So there'll be a couple of percent of people, like two or three percent people listening to this who could have both. And their risk really would be much more because eight times higher on something that's relatively common sounds like that's a very high risk. But you're saying they're not doomed to get this if they have these two genes? 

[00:16:01] Claire Steves: No, no, absolutely not. Well, we don't actually know completely why APOE e4 confers the risk. But it's something to do with the way that our brain cells use fats in the body and it's probably influenced by things in our diet and maybe medications that we take. So that's why you know you can still increase your resilience even if you have two of those APOE e4 alleles. 

[00:16:29] Jonathan Wolf: So could you talk a bit more maybe about the thing because the gene, I think the thing about genes is always it's so depressing right like you have your genes and you're sort of stuck with them. 

I think one of the joys for me about this journey with ZOE is realizing that almost everything that I've been taught that basically, we were just sort of this victim of our genes that was going to define our health. Turns out not to be very true. And that actually the way that we live our life is much more important in terms of certainly most aspects of our health. 

Though, as I keep telling my journey. My son, it seems like our genes are still quite important for your height, and since I'm rather short, he's rather disappointed that he's not going to be, you know, six foot five. 

But it seems that in general, actually, the height is a bit of the exception, and in general, in our health, we have much more control. What are the other things that mean that people are at higher risk of dementia? 

[00:17:11] Claire Steves: Well, if we start, like, early on in life, really important, because ultimately, all of our cells in our body are aging right from the beginning, when we're, after we've conceived. So, you know, even things in utero can be really important for later life development. 

[00:17:24] Jonathan Wolf: This is while I'm a, while I'm a fetus. 

[00:17:26] Claire Steves: So if you're any pregnant mums out there, you know, actually, what you're doing is preparing your child for the whole of their life. So it's really important to be thinking about that and making sure that you're giving them the optimum.

[00:17:36] Jonathan Wolf: I always think it's also terrible as we both have children, there's enough pressure I always feel on pregnant mothers, it's pretty tough, I think. And then now you're just about to layer on some more, but go on. I know this is a science. Tell us. 

[00:17:49] Claire Steves: But also society needs to do that as well. Really. I mean, that's really a key message for society. We need to really look after it. 

[00:17:54] Jonathan Wolf: Pregnant mums. That seems unobvious. How does what happens to me as a fetus affect the things that will change my risk of dementia? 

[00:18:02] Claire Steves: It’s about cognitive reserve. So that's the kind of maximum cognitive ability that we might have, not just in terms of sort of intellectual ability, but also psychological state as well.

So the reason why that's really important for dementia is that dementia is something whereby our functions are interfering with daily life. And obviously, if we start off with really high functioning, then we get to that point much later in any disease process. So you can put off significantly the time at which you fall below that threshold of being able to function in daily life much, much later.

[00:18:37] Jonathan Wolf: Could you explain a bit more what you're describing? What is it that some people are getting and other people are not?

[00:18:41] Claire Steves: We can think about it from multiple different ways. Yeah, we can think about it in terms of the stimulation that a child is being given through education, through parental influence.

We can think about it psychologically around that development that's happening in early childhood. But we can also think about it about nutrition, as we talked about, you know, before, I'm sure we'll talk about again. Nutrition starts in utero. There are factors which affect how the brain actually develops right from the beginning.

And then, you know, we can then go even further than that and talk about things like smoking and alcohol, which have significant effects on the brain development of children.

[00:19:16] Jonathan Wolf: I think I'm understanding better now. I think you're saying right back, even when you're as a fetus, depending upon the nutrition that your mother is having, that's going to affect the way your brain is developed then after you're born, continuing the food that you eat as a child, but also you're saying the stimulation you get, I'd love for you to talk a little bit more about that.

You're saying that somehow the way that the world is interacting with you. Is going to give me a, I guess, like a healthier and more robust brain that is actually going to have an effect on whether I get dementia 70 or 80 years later. Is that…

[00:19:47] Claire Steves: You might still get dementia, but the chances are that the more that we can do to increase brain reserve, the later…

[00:19:53] Jonathan Wolf: Brain reserve is like the capacity of your brain to do  things?

[00:19:56] Claire Steves: Yes, exactly, exactly. So, and humans are incredibly varied in terms of their cognitive functioning. And so if you have a high cognitive functioning, obviously you've got further to fall. 

[00:20:09] Jonathan Wolf: It's a bit like saying my tank is, it's a bit, I'm thinking about now a bit like a car. So the fuel in the car is your reserve. And when it goes below a certain point, you know, the car stops working. 

And is that your analogy a bit here with the brain that you're saying you might have dementia, so your reserve is being reduced, but because it's very capable, you can go a lot longer before it stops working. Is that…?

[00:20:30] Claire Steves: And so actually the processes might still be happening within that brain, but actually then it doesn't play out in life.

And this is really important because obviously that investment that we give, or we can give if we have the capability to give it, that investment will last out and make a difference later on.

[00:20:46] Jonathan Wolf: Got it. Because it might be that, okay, yes, you are signed to have dementia. And if you became a hundred, it would be really affecting you. But actually, if you die at 85 of a heart attack or something, then actually your brain was fine. Is that what you're describing? 

Could you talk a little bit more about this, I think everyone listening to this is probably thinking, okay, how do I make sure that maybe starting with perhaps thinking about their children or their grandchildren, how do they make sure their reserves are good?

And then also perhaps what's happening later. But right now I think you're talking about like earlier life. What is it that gives you these higher reserves, you know, before you're 18, I guess. 

[00:21:21] Claire Steves: Yeah. So, I think we've already talked about diet. We've talked about intellectual stimulation, sort of also that stability, psychological balance, which is really important. Mental health. 

[00:21:31] Jonathan Wolf: So mental health is linked. 

[00:21:33] Claire Steves: Well mental health is really interesting because good mental health sets you up for a cascade of good things then happening to you late in life, which then give you more opportunity, more capability to take on these opportunities to then improve your brain reserve and stimulate your brain.

Whereas problematical mental health. then can lead to difficulties in the capability or the opportunities and motivations to take on these things that are going to then help your future brain reserve. 

So talking about some of those, I mean, the key things are around social stimulation, things like physical fitness. I think I talked about that a lot in the last podcast, that we know that physical fitness is really beneficial for brain health. And of course, we can then put in some physical reserve as well. And habits of daily life that then increase our physical activity and continue it going through midlife, which is going to be good for vascular health, but it's also really good for brain health.

[00:22:30] Jonathan Wolf: So if I am doing more physical activity, what does that mean for my brain? 

[00:22:36] Claire Steves: The habit is good. It's the daily, regular, physical activity, which doesn't need to entail exercise. It's the reduction, even in sedentary time that we see has an effect, not just on dementias, but actually on brain aging as well.

[00:22:51] Jonathan Wolf: So that just means my brain is effectively younger.

[00:22:56] Claire Steves: Yeah, which increases that reserve. 

[00:22:57] Jonathan Wolf: That description you gave at the beginning, which is a bit depressing about like not being able to respond to anything or really know what's going on. If I'm regularly active, when I'm 70 or 80 or 90 or 100, some of my mental clarity is just gonna be a lot better, is that what you're saying, because I've been consistently active.

[00:23:13] Claire Steves: Active, yeah, that's right. So active, but not just in terms of physical activity, active in terms of social activity, and all those things, those all contribute to brain reserve. 

But then there's also things that sort of, you know, alter brain reserve and make it more tricky for us to maintain those cognitive functions. I'm not talking about the proteinopathies now, I'm talking about the reserve capacity. And of course that's where interaction with other body systems is really important. 

So we know that there's a real strong interaction between cardiobiotic health and brain health. We know that there's a really strong interaction between, say, for example, our hearing ability, our sensory ability, and brain health. Then, likewise, infections can tip the balance of brain health, but chronic inflammation can also affect how our brain's resilient to those changes which might happen in that balance between proteins being set down or not.  

[00:24:07] Jonathan Wolf: So, before we start to talk about prevention, which I know everyone listening is like, that's really interesting. It all sounds quite scary, let's talk about everything we can do. 

I'd love to talk a little bit about symptoms and what the status of treatment is at the moment first. So could you tell me if someone's thinking about the symptoms that they might notice in themselves or a loved one that would sort of probably trigger this thing that I think, you know, we should maybe go and talk to a doctor.

What should they be looking for? 

[00:24:34] Claire Steves: So really it's about a change in cognitive function and different dementias have different patterns. But as I've talked about, you know, we've got things like Alzheimer's dementia, which starts with short-term memory loss. 

There's other forms of dementia that can start with personality change. Again, further forms of dementia, actually the first presentation is around falling over and maybe difficulty with the blood pressure regulation, sleep even, sometimes can be the very earliest presentations of some forms of dementia.

[00:25:05] Jonathan Wolf: When those symptoms start to become common enough that you might be sort of on the alert for it. Because again, I think many people listening are feeling like, ah, as people get old, I'm expecting this to happen and I'm sort of on alert. become very vigilant about it. 

[00:25:19] Claire Steves: Good question. So most people that are referred to my memory clinic are probably in their seventies. Okay. It's quite rare to see people in their forties being referred to me.

If people do have these problems happening in their forties, then they're more likely to go and see a neurologist for an examination. But yes, so those are the more common ages. 

[00:25:38] Jonathan Wolf: Seventies is sort of when you're tending in fact to see them in your, in your clinic. And so what are the treatment options?

And I think I've definitely seen there's been a lot of press about new drugs starting to come on board. What's the situation today as a doctor thinking about treatment for somebody who comes in and who you do diagnose? 

[00:25:57] Claire Steves: Yeah, so it's really exciting that we now have some new drugs because we've been waiting actually about 20 years for some new changes in drugs. 

What these drugs are doing actually, it's a really amazing proof of concept. That these medications, they're basically antibody based medications that are sticking to the proteins and getting rid of them, clearing those proteins that we talked about at the beginning. 

And we've known for some time actually that we can do this and take them out, for example, from animal studies. It's only really been in the last year that we've had evidence that taking out those proteins In the case of Alzheimer's disease, actually has an effect on human progression of the disease. But the issue is that actually when we do that, the level of gain is actually quite modest. It doesn't…

[00:26:44] Jonathan Wolf: You mean when someone takes these drugs?

[00:26:46] Claire Steves: Yeah, so we can take the proteins out of the brain. Right. But it doesn't necessarily mean that we've significantly affected their cognition and their function.  

[00:26:52] Jonathan Wolf: We hear about all sorts of wonder drugs, right, that suddenly solve everything. And then you hear about other drugs where people say, oh, well, it doesn't really, ultimately didn't really make much of a difference.How excited are you about these new drugs?

[00:27:03] Claire Steves: Well, I'm excited in principle. I'm excited in principle because we've shown a proof of principle that this works in humans and therefore it could be developed on. 

But the issues are this, that first of all, the gain over a year is only a few points on a cognitive measure. So it doesn't mean that the person then doesn't have dementia. It's just that their dementia is, they're not cured. They probably are, you know, the process is slowed though. That's the game changer. The process is slowed. Whereas before we've been able to give drugs that manage symptoms, but ultimately the process isn't slowed.

So that's the really exciting game change. 

[00:27:41] Jonathan Wolf: How much slowing down are they delivering? 

[00:27:43] Claire Steves: So at the moment, not very much slowing down. But we haven't, we haven't talked about the main problem with it. The main problem is, is that actually there's increased risks. 

So as you're taking away the proteins from the brain, you're also increasing the risk of edema happening in the brain. So that's swelling, swelling in the brain, which can be quite catastrophic. If the brain swells a little bit, there's inside a fixed space, there's an increased risk of hemorrhage, little microhemorrhages within the brain. And so people that are having these drugs, there's bleeding, yeah. So the people that are having these medications have to have a scan every month.

[00:28:16] Jonathan Wolf: And so what does that mean in reality there? Because those sound like quite scary side effects, are they rare? 

[00:28:22] Claire Steves: It means that actually, the balance of risks and benefits is not totally clear, ultimately.

[00:28:27] Jonathan Wolf: So as a doctor does that mean you're not necessarily just saying to everybody who comes in, you should take this drug?

[00:28:32] Claire Steves: Well, they're not approved in the U.K. for that reason. 

[00:28:35] Jonathan Wolf: And they have been approved in the States? 

[00:28:39] Claire Steves: They've been approved in the States, yeah.

[00:28:41] Jonathan Wolf: Okay. But when that happens that tells you it's a bit on the edge, is that what you're saying about the balance of benefits and…

[00:28:43] Claire Steves: I think the benefit and risk is definitely on the edge if you had all the resources available. And then you've got to think, well, actually, how are we logistically going to get everybody to be able to have scans every month? And what knock-on effect is that going to be on being able to get scans for cancer or scans for other things? 

So there's a resource issue as well. So if the gain was massive, then you might say, well, that was worth that risk personally, and also as a healthcare system.

[00:29:07] Jonathan Wolf: And how many extra years of sort of well-functioning brain am I going to get? 

[00:29:12] Claire Steves: So we don't really know yet as well, because we've only had a couple of years of lead time. 

[00:29:18] Jonathan Wolf: Got it. But if you're going to guess, are you talking about like a year or are you talking about like an extra decade? 

[00:29:24] Claire Steves: Yeah, it's not an extra decade.

[00:29:28] Jonathan Wolf: This is not the sort of transformational drug that means we are just, we feel like we've conquered dementia. 

[00:29:30] Claire Steves: No, but it is a transformational drug because it's showing us the proof of the idea that it is possible to take away the proteins from the brain. So all we need to do is do that more safely. And we need to try doing it in different proteins because it may not be the proteins that we've gone after that's the key. 

[00:29:46] Jonathan Wolf: This approach can work and then maybe this generation of drugs are not ideal. But you're sounding quite optimistic that maybe this means there's a path to a next generation.

[00:29:55] Claire Steves: There's a path to a next generation. Within the next five years, we need to really get our services in order so that we can be thinking about delivering these things because it's coming.

[00:30:04] Jonathan Wolf: So that's very exciting. So if you're living with maybe a family member, who's having this today, then it may not be as positive as you'd like.

But if you're thinking about what might be happening in a decade to a family member or yourself, then actually sounds like this is quite positive, which is exciting. Like the science is really moving forward. And I know you're quite careful, Claire. So the fact that you're quite positive here, it makes me feel that you're feeling actually really quite enthusiastic about the potential in the longer term.

[00:30:32] Claire Steves: Yes, that's right. 

[00:30:34] Jonathan Wolf: Well, look, I think I would love to switch to the stuff that doesn't involve taking a drug that might make your brain explode, because I can understand why that might not be ideal. Let's start with me. So, you know, I'm someone in my late 40s, I really want to make sure that I don't have dementia.

Give me the advice. If I was walking into your clinic, tell me what you would be saying that I should be doing in order to try and make sure I never had to come back to your clinic in 20 years.

[00:30:58] Claire Steves: So actually what I realistically say to patients is, it's about getting as many different colors of fruit and vegetables into your diet as possible and making sure that you're getting good plant-based fats into the diet.

Because the brain is hugely metabolically active, it needs a lot of nutrients and we know that a wide variety of plant-based, nutrients is really important for brain health. And I talk about colors because actually there's evidence that flavonoids are really key phytonutrients for brain development.

It may be because you're changing the microbiome because there's such a thing as a gut-brain axis. So we think that there's a very strong relationship between what's going on in our gut. 

[00:31:36] Jonathan Wolf: So there lots of plants with lots of fiber, lots of different colors. And then you said lots of health fats, which means a lot of plant-based fats.

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And so you, I think you were mentioning nuts. We often talk about things like avocados, right, at ZOE. These are the sorts of things that you're talking about. 

[00:31:53] Claire Steves: Yeah. And I think that's right. And you know, there's quite a number of studies now showing Mediterranean diet, it helps to improve cognitive health.

[00:32:00] Jonathan Wolf: So that there is real evidence that the Mediterranean, like changing this isn't just like something, cause you know, doctors always say you should eat more healthily. Right. And everyone's like, yeah. There's real scientific studies that show that switching to this Mediterranean diet, which is high in the things you're describing and low in like the more traditional Western diet of meats and like white bread and all the rest of it, like that actually has an effect on dementia?

[00:32:23] Claire Steves: Yeah. And then you, so you just mentioned the other thing, which is meats and white bread. So we know that there's a relationship between vascular health and brain health. 

[00:32:34] Jonathan Wolf: And vascular health means?

[00:32:34] Claire Steves: The blood vessels within your body and your heart. That's because one of the other types of dementia that we haven't really talked about is a vascular dementia. And often there's a combination, actually, of vascular factors that then bring on those other processes like Alzheimer's. 

[00:32:50] Jonathan Wolf: So if you're eating a diet that's good for your heart, basically, that’s also going to be good for your brain.

[00:32:56] Claire Steves: Yeah, it's going to be good for your brain and it's going to, you know, put backwards the balance of things that are going on in your brain that might relate to Alzheimer's. 

[00:33:04] Jonathan Wolf: There is real scientific evidence that this shift in diet really can reduce your risk of dementia?

[00:33:09] Claire Steves: So, for example, in the Mediterranean diet, there have been really large randomized control trials that were conducted over a year period of, in five different countries in Europe. And when they compared the group that were randomized to the Mediterranean diet against the control group, they didn't find.very significant differences. 

[00:33:30] Jonathan Wolf: If you manage to change your diet in a sustainable way, it really can reduce your risk of dementia. But you have to stick at it. You have to stick at it. You can't just do it for a few months. 

[00:33:38] Claire Steves: And the trouble is, that's difficult. 

[00:33:40] Jonathan Wolf: What else would you tell somebody? 

[00:33:42] Claire Steves: So the second thing is about physical activity. So, you know, I do tell all my patients to make sure they're physically active at least three times a week, and they're going out every day. These are really important things to do, and that can help preserve your physical function as well, and your cardiovascular function. It's probably the biggest thing that you can do to help your overall fitness.

[00:34:02] Jonathan Wolf: And when you say physical activity, when you're thinking about dementia, what's really required? Because we talk to a very wide range of people who vary between, if you even get up from your chair for two minutes, you've done everything like amazing to, you know, if you're not doing a massive workout four times a week, then you're sort of dooming yourself.

But what should people be thinking? Like, this is what I really need to make sure that I'm building. 

[00:34:28] Claire Steves: So to improve your cognitive health, you need to do more exercise than you're doing now. Okay, up to a point, unless you're like an Olympic athlete. So that's the, and that's the key thing. Okay. 

So, and this is again about the difference between scientific proof and practical advice. So the reason why there's this debate between scientists about what is the dose required of exercise, is because to show a change over a short period, you have to have a big enough dose to be able to detect that effect.

Whereas if we look at really big population studies, we can see effects even with minimal levels of exercise and it's fairly linear. So even being more up and about, less sedentary time, makes a difference. But then you can still make more difference by putting every effort on. So whatever you're doing, if you go up by a third, you'll be improving yourself.

[00:35:20] Jonathan Wolf: And is there any particular sorts of exercises you're thinking about this? 

[00:35:24] Claire Steves: So probably the most evidence is around resistance training exercise for overall frailty and so on. Then, you know, for cardiovascular fitness, there's aerobic exercise. 

[00:35:35] Jonathan Wolf: I'm one of your patients. I'm not very physically active. What would you be telling me that I should do that can really make a difference?

[00:35:42] Claire Steves: Walking. 

[00:35:43] Jonathan Wolf: Walking. 

[00:35:44] Claire Steves: I think you need to get out and do walking 45 minutes, at least three times a week. 

[00:35:48] Jonathan Wolf: And that would really make a difference. If I'm not doing that, that would really make a difference. So that, I think again, is amazing, Claire, I think you were like, well, it seems sort of obvious. But again, I think many people listening to this grew up with the assumption there is nothing you can do about it, it's just literally a consequence of getting older. 

And you're saying actually, if you went reward three times a week compared to just not doing that, you're going to make a really significant reduction in risk is rather extraordinary and does suggest that, you know, our current way we live our life is not very well optimized for avoiding this. If that is almost like your starting advice to people with that. 

[00:36:25] Claire Steves: One thing I haven't really talked about ever before with you is teeth, the importance of teeth. In the U.K. population, about 35% of older adults have periodontal disease, inflammation of their gums. And we know there's quite a strong tight relationship between periodontal disease and cognitive health.

[00:36:41] Jonathan Wolf: And this is, you believe this is true? Because we had somebody on, just if anyone's interested, a few weeks ago, we'll put a link, who was a dental researcher saying this. But I was curious, because obviously, if you're a dentist, you're going to be convinced that the teeth are important.

[00:36:53] Claire Steves: I really think it's really true.

[00:36:55] Jonathan Wolf: And you're not a dentist, so therefore you're unbiased on this. This is really true, is it?  

[00:37:00] Claire Steves: It's really true.There is a vicious cycle, though, obviously, because as you start to get dementia, it's more difficult to look after your teeth. And also, we know that, that looking after teeth, actually diet is really important in looking after teeth.

So teeth are much more healthy if you have a good varied diet that we've been describing and less sugar and so on and so forth. But actually, you know, this is a very common inflammatory load, which is tickling the systemic inflammatory system. 

[00:37:25] Jonathan Wolf: Which is amazing. I just heard this literally a few weeks ago. I was shocked to hear this. 

[00:37:28] Claire Steves: So, and actually when I see my patients in clinic, okay, the thing that sort of, just eyeballing. The thing that's related to that cognitive reserve we were talking about, i.e. the difference between what's in their brain and how they're actually living, you know, how they actually present. 

The people that have the bad teeth will be doing badly. The people that have the good teeth, will be doing well. 

[00:37:52] Jonathan Wolf: You would be saying if someone is having problems with their teeth, like absolutely going to get it fixed right away, because that really could be a big risk factor. 

What else could people do? And I feel like you mentioned a little bit about intellectual stimulation and social stimulation. Is there anything you can do with your, is this all fake?  That you, that, you know, doing things with the brain can help prevent dementia, or is there something real about this?

[00:38:13] Claire Steves:  Well, no, I think the thing is, it's about that cognitive reserve as well. Again, okay, so I don't think we mustn't be getting the idea that if you've got a, you know, managerial high-paid job, whatever, you're doing lots of intellectual activity that you're immune to dementia. Everybody can get dementia, it's just that you will present later.

[00:38:34] Jonathan Wolf: So I'm in my late forties, I'm thinking about this right now. Is there anything that I could be doing with my brain over the next 20 years that will change my risk factor? Is there anything I can do there that is actually going to shift it? 

[00:38:49] Claire Steves: Probably one of the most complicated things that we do in our brain is to really interact socially. And so that's is better than a crossword puzzle. 

[00:38:59] Jonathan Wolf: I think much more fun as well. So it's good news.I know not everybody feels that way. Some people who are more introverted feel this is hard work. 

[00:39:06] Claire Steves: But it doesn't necessarily mean that some of these brain games aren't helpful. I think the thing is that what brain games tend to do is, they tend to make you better at that brain game. They don't necessarily…

[00:39:16] Jonathan Wolf: You’d have lots of different brain games.

[00:39:17] Claire Steves: You'd have to have lots of different brain games. 

[00:39:18] Jonathan Wolf: Okay. So it's not that bad, but actually you're saying social interaction is so complicated for our brain. That's really exciting, which also I guess ties into why loneliness is, another reason why loneliness is not good for us. 

[00:39:31] Claire Steves: Yeah. And then physical activity, certain physical activities are really taxing for the brain, aren't they? In terms of activity. So if you're like cycling in London, that's for sure quite taxing.  

[00:39:40] Jonathan Wolf: Yes. I always think that it might be lowering your life expectancy for other reasons. 

[00:39:44] Claire Steves: Yeah, but there are other sort of forms of physical activity like dancing or whatever, which is quite a good cognitive task.

[00:39:51] Jonathan Wolf: Essentially what you're saying, because your brain is having to think quite a lot as well. So basically what you're saying is using your brain, making it have to do something that is actually going to build what you're calling this reserve, which is basically meaning you're less likely to suffer from it.

[00:40:04] Claire Steves: Your tank, what's in the tank, yeah. 

[00:40:05] Jonathan Wolf: We had a lot of questions from our listeners about the link between blood sugar levels and the risk of dementia. And in fact, some of them said that they've been hearing people refer to Alzheimer's disease as three diabetes. In other words, that because we've seen this huge rise in the number of people with type two diabetes because of our diets and you know, all of this high blood sugar that actually this was potentially a risk that was increasing the risk of Alzheimer's.

Is this true or another one of these pseudoscience? 

[00:40:33] Claire Steves: No, we know that having diabetes increases the risk of dementia of probably of all types actually. Significantly. And then, you know, you do have to be a bit careful if you have dementia and you have diabetes, because it's not quite as simple as having really tight control of your diabetes in that case. Because we know the brain in the context of dementia, you know, does need blood sugar and actually low blood sugars is really dangerous.

[00:41:02] Jonathan Wolf: This is once you have the dementia, but this is what you're saying, or once you have the diabetes. 

[00:41:08] Claire Steves: If you're early in life, you know, and we're talking about the preventative stage, everything you can do to help your blood sugars be normal is better. So overcontrol probably isn't very good for the brain, but ultimately the bigger thing is around…

[00:41:23] Jonathan Wolf: Eating too little is not a good thing. Is this what you're saying? 

[00:41:25] Claire Steves: Well, no, it's not about eating too little because of course the liver produces the glucose and so on. So, you know, having a really low blood sugar is not good for the brain for sure. But the main problem is around pre-diabetes or diabetes. 

[00:41:37] Jonathan Wolf: This is real. This like, this rise in pre-diabetes and diabetes is a real contributory factor. And then presumably that means if you can reverse the pre-diabetes or suddenly, you know, control the type two so it doesn't continue to get worse, that would lower your risk of getting dementia?

[00:41:55] Claire Steves: That would lower your risk of getting dementia. 

[00:41:56] Jonathan Wolf: Brilliant. We had one other question from the community that I definitely want to ask, because it came up quite a bit. Should women be taking HRT in order to reduce their risk of dementia as they go through menopause? 

[00:42:08] Claire Steves: That's a very interesting and controversial question.There's quite a few studies that you may be aware of that have happened in the last year, which have produced conflicting evidence. 

[00:42:17] Jonathan Wolf: I'm not aware of them, so please, but I can tell that some of our listeners are, and they, of course, therefore, probably sitting here trying to decode that. What do those things say? What's your reading of what that means, as best we can understand with the latest sciences? 

[00:42:32] Claire Steves: HRT is not going to be a cure-all. That it probably will contribute to reserves, but also it really helps in active day-to-day cognitive function of people going through the menopause. So that's probably where it's really important to use it. Because people who are going through the menopause often have problems with brain function, which can be really debilitating.

[00:42:53] Jonathan Wolf: I've heard some extraordinary and awful stories and, you know, I said, I've talked about this before, that I've been shocked, because it's not something when I was growing up that my mother never talked about. Nobody I knew talked about. And so as I started to hear some of these stories more recently. It's really extraordinary to me how some people have such a tough time for years.  

[00:43:13] Claire Steves: The reason to take HRT is to help that, which is, you know, really important. 

[00:43:18] Jonathan Wolf: And it can really help brain function through this. 

[00:43:20] Claire Steves: Yeah. That's right. Then worrying, you know, dementia later on, I don't think that's a reason to take HRT now.

[00:43:28] Jonathan Wolf: Got it. And you're saying at this point there isn't data that says this has this profound impact later on that makes you shift? 

[00:43:36] Claire Steves: No. In fact, there's studies that go both ways on this. Okay. So I don't think we should be taking HRT because of future risk of dementia at the moment, unless, let's see what happens. 

Because actually the longitudinal studies, you know, bear in mind that people have only been using HRT for the last 30 years or so. So, you know, and who took it and who didn't take it is confounded by other things. So it's a space that we, that is uncertain, but what's not uncertain is that many, many women who have problems with cognition during the menopause benefit from HRT. 

[00:44:09] Jonathan Wolf: One of the things I've been really struck through this ZOE journey over the last seven years is how much in science we don't know the answer to, and how much is this constantly ongoing investigation.

And I think one of the ways I always judge whether you're talking to a really good scientist, is their caution in lots of areas where they say, I think, as you just have done Claire, like the evidence isn't really there yet. And there's lots more studies. And, you know, I think one of the joys of science is that, however, we are making progress.

We definitely do know more than we did 10 years ago. And I think this is a lovely example of that, where I think you're saying it's not yet clear. It sounds like it could be, you might be sitting here in five years time saying, actually, I'm looking at all the data. And I do believe that this can really be beneficial long-term against dementia, but that actually at this point, the data isn't clear. And I feel that happens a lot in science to do with, you know, the human body because it's so complicated. 

I have so many more questions, but I think that we have run out of time. I'm going to try and do a playback. This is a new topic for us and quite a complicated one. So please correct me if I get any of this wrong, is that all right?

I think what you described to start with about what is dementia, is really contrasting it with sort of normal, healthy brain behavior. And so, for example, you said the warning signs are things like starting to lose your short-term memory. So not remember something maybe from five minutes before. Or not be able to function with some, it seems like normal life, but maybe it's a bit complicated, like managing your finances or making sure you're doing your medication properly. And that we have to bear in mind, however, that our brains do age as well, even though that's hidden to us.

And so I think you're saying like, you know, if I looked inside my brain, you said this horrible word atrophies, which has a depressing idea. But also, for example, you can see that your reaction speed just naturally gets slower. So the point is, it's like outside of that, but generally this is a slow progression.

So unlike, you know, a lot of diseases, it's sort of like bit by bit, rather than suddenly presenting with this very clear, different function than you had last week. That it's caused by nerve cells in our brain dying. This is what's causing the problem, but that we can see the cause over time with these sort of proteins being stuck in these nerve cells. 

And that indeed, you're quite excited because there are some new drugs coming that are clearing these proteins away. And although this current generation, you feel like the balance between benefit and harm is not that great. You're quite excited about where it might go in the future.

Then we talked a bit about why you might get dementia. You taught, there are some specific genes. So I think you said something like an E4 gene. Is that right? If you had two of those, then you have not won the lottery. But even then it's not guaranteed that you're going to get this. So that in all cases, actually, there's a lot through your lifestyle that you can do.

And I think the way that you helped me to understand it is to think about your brain has this brain reserve. It’s not a word I'd ever heard before, which is sort of like this tank that you're filling up with all this capacity. and that starts actually, even when you're a fetus.

So we can build the brain reserves of unborn children by, you know, the food that their mother is eating. But then, as they're born, like how much stimulation they have their own food, all the rest of it. But you can keep building this reserve as we're older. And so even if we might start beginning this dementia, if your reserve is big, actually you can live much longer in a healthy way. 

And then I think in terms of the things that we can do, I think the number one thing you talked about was diet. And I thought was interesting. You were very strong about how switching diet to something that looks like a diet that is very plant-based with lots of different sorts of plants. You were describing sort of eat the rainbow things with a lot of fiber in them, lots of healthy plant fats. I think you mentioned nuts, for example, specifically that's sort of the number one thing.

I think the number two thing you said is physical activity. I think you made this great quote to improve your health. You need to do more than you're doing today. So almost whatever you're doing, if you want to reduce further your risk of dementia. But interestingly, you were saying that actually for most people, it's just like going out every day, going for a walk, if you're not already doing that, will have a profound reduction. And Claire is nodding her head hard at this point, if you're listening on audio, a profound reduction in your risk of dementia. 

Look after your teeth. And then intellectual stimulation, particularly just meaning with other people. So socially social interaction, actually being almost the best brain training you can do.

And you said that there are all these different brain training tools and that's fine, but actually they need to be changed all the time, but actually just sort of interacting with other people a lot, probably is pushing your brain more than anywhere else.

And then I think finally we said diabetes is a risk. So you want to avoid diabetes or you want to have it under control, if you have type two diabetes. 

And HRT, you know, the, the evidence isn't there as a cure for dementia in the long term, but there is great evidence about how it improves your cognitive function during perimenopause and menopause, and that's a big deal. So you should be embracing it, if you have those issues. 

How did I do? 

[00:49:12] Claire Steves: Yeah, really good. Can I add a couple of little things? So one is around dementia. When we were talking about it, we were mainly talking about the biggest form of the most common cause of dementia, which is Alzheimer's, but remember it's an umbrella term. And so there are lots of about 25 different other types of dementia and they do present differently. 

So ultimately that key is, you know, is there something changing and changing consistently over time in the functioning of the mental capacity of that person? And that's when to seek help. So don't not seek help just because short-term memory isn't the issue.

And then the other thing that we didn't talk about today, but is really important is sensory inputs. So ultimately in the same way that social sense, social interaction is really important. Our interaction with the rest of the world sensorily. So we know now that actually hearing aids, if you've got hearing impairment, delay the presentation of dementia.

[00:50:10] Jonathan Wolf: That's amazing. So if you get, I think I remember you talking about this in our conversation a long time ago, you're saying if you get a hearing aid, that actually reduces the point at which you get dementia. 

[00:50:16] Claire Steves: Exactly. So don't delay on doing those things. And I think, you know, some people think, oh, I don't really want to hear, you know. Actually it does make a difference. So do get those hearing aids, even if it's a pain to start wearing them at the beginning. 

[00:50:30] Jonathan Wolf: Because that's as good as going for an, I'm not saying it's instead of, but I mean, we're talking about, it has the same sort of impact as you're describing with going for a walk?

[00:50:37] Claire Steves: Actually, I don't know whether I can quantify the difference. Yeah, I think it's probably, yeah.

[00:50:41] Jonathan Wolf: This is like a big deal. 

[00:50:43] Claire Steves: Yeah. It's a big deal. 

[00:50:44] Jonathan Wolf: Amazing. Well, I think the hearing aid providers around the world are going to have a busy week I think after that. 

Claire, thank you so much for unpacking that. And I think it was really clear. This is a complex topic. And I think having done that first overview, I am sure we'd love to come back and dive into some of that again in the future. 

[00:51:02] Claire Steves: Thank you very much. Brilliant. Thank you. 

[00:51:04] Jonathan Wolf: Thank you for joining me on ZOE Science &Nutrition today. It was incredible to learn from Claire just how much we can reduce the risk of dementia, including the critical role of eating the right food for your body.

Now, if you'd like more actionable tips from the podcast, you can download our free guide with 10 of the most impactful things you can do to improve your health. Simply go to zoe.com/podcast, or click the link in the show notes. On the same link, you can also learn more about how becoming a ZOE member can give you specific advice about what to eat for your body that can help you feel better now and reduce the risk of dementia in the years to come. You can also get 10% off your membership.

As always, I'm Jonathan Wolf. ZOE Science & Nutrition is produced by Yella Hewings-Martin, Richard Willan, and Tilly Fulford. See you next time.

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