Three ways to prevent diabetes with Professor Naveed Sattar

0:00Welcome to ZOE Science & Nutrition, where world leading scientists explain how their research can improve your health.

0:14Today, we're tackling a silent killer that's claiming more of us every year. It's a disease so widespread that it touches nearly every family in some way. Type 2 diabetes. This is not just a health issue. It's a rapidly expanding crisis. And many people don't even know they have it. In the US alone, 100 million people have prediabetes, and over 37 million grapple with type 2 diabetes. Globally, the last 30 years have seen a fourfold increase in the number of people living with this condition. And this isn't just about high blood sugar. This is a serious chronic disease that can rob you of your vision, your limbs, and even your life.

1:01But there is hope. Professor Naveed Sattar joins us today to tell us how to prevent, treat, and even reverse type 2 diabetes. Naveed is a medical doctor and professor of metabolic medicine at the Institute of Cardiovascular and Medical Sciences at the University of Glasgow in Scotland. He's one of the world's top 1 % most cited clinical scientists and has worked on many clinical trials of lifestyle changes and drugs to prevent and manage diabetes. Naveed has also been a member of Zoe's Scientific Advisory Board and an important contributor to Zoe's science in this area.

1:38Naveed, really lovely to see you again. Thank you for joining me today. Pleasure, Jonathan. So we have this tradition on the show that we always start with a quickfire round of questions from our listeners. And the rules are really simple. You can say yes or no, or if you absolutely have to, you can have one sentence to answer it. It's specially designed to be really hard for professors. Are you willing to give it a go? Cool for it. Yeah, absolutely. Yeah. All right. Are there millions of people around the world who don't know they are living with type 2 diabetes? Yes. Does type 2 diabetes significantly increase my risk of other diseases like heart disease and cancer?

2:20Yes. Is it true that almost 100 million Americans have pre-diabetes? That seems a high number. It's possible. I think it's probably slightly overestimated, in my opinion. OK, let's go and dig into that. That is a quote from the CDC, so I'm intrigued to go into that. If the food I eat leads to big blood sugar spikes day after day after day, can this significantly increase my risk of type 2 diabetes? Probably yes, but it would generally tend to do so through weight gain. are women better at controlling their blood sugar than men? Women have a lower risk of type 2 diabetes than men for reasons linked to where they store body fat.

3:04I think we'll definitely want to talk about that. And then finally, last question, and you definitely can have a sentence or two for this one, Naveed. What's the biggest myth about type 2 diabetes that you come across as an expert in this area? Certainly my patient's biggest myth, often when I tell them that they may have type 2 or at risk, is that they don't eat much sugar. Type 2 diabetes predominantly is a disease of excess. In most people, excess weight to a level in themselves that leads to too much fat in the wrong places, including within the liver. Got it. And so they're saying, hey, but I don't eat loads of sugar, so how can I have type 2 diabetes?

3:44And the answer is they still do. They still do. And it's predominantly, people can put on excess weight for a number of reasons, not necessarily just high sugar, but also obviously lots of fat. Well, look, let's start to dive into all of this. And just to start with, I think many listeners to this podcast know I have a personal interest in blood sugar because my own blood sugar control is actually really quite poor. But I actually didn't know this was happening inside me at all until I wore a continuous glucose monitor when I took part in the very first Zoe Predict clinical trial, which is about five or six years ago.

4:19And it was a complete eye-opener for me, understanding that my blood sugar would often be very high for hours after I ate certain foods and was quite high, you know, even when I woke up in the morning fasting because I didn't feel anything. I had no idea about this. So, you know, I'm really fascinated in this topic. Now, before I get carried away though and jump to all the things that I'd love to discuss about what I could do to improve my blood sugar control, can we just start right at the beginning and maybe just start with like, what is blood sugar and why does it matter? Well, sugar is one of the fuels, one of the key fuels that many body cells require for making energy and for conducting the normal function.

4:59So particularly, of course, the brain, dependent upon fuel for it to function. And it's its source of fuel for it to work, for the cells to work, as well as requiring oxygen. it's also when we are sick the body is very good at preserving trying to preserve sugar for your immune cells the cells that fight and off infection or help repair tissues and again they require lots of fuel for that for those mechanisms to fight off infection or repair tissues and therefore when you are sick it makes sense the body tries to preserve sugar more for those cells. But it's required, sugar is required for all body cells, basically for them to function normally.

5:41And one of the things I think that often gets, people often mention when they talk about diabetes, you often hear this word insulin. What is insulin and why does it ever come up in the discussion around blood sugar and diabetes? So insulin is a hormone. So if I was to, and I've just eaten a banana and my body is breaking down that banana, putting its breakdown products, one of which is sugar into my blood. But I don't want it to be my blood for very long. I want to be able to store that energy in various tissues. Insulin is a bit like a key that opens up some of my cells to take in that sugar and store it when I don't need it.

6:20This also stops my own body making sugar when I don't need it. So I've just had a lot of sugar. Hopefully my insulin starts to go up, put the sugar in the right places. And it's also probably signaling into my liver, stop. You don't need to make any more sugar because there's already lots coming in. So it's like a master regulator of keeping sugar levels within the right levels in the blood, putting it in the places where you need it to store for future needs, and also helping you liberate it when you need it. And that actually happens when the insulin levels go right down. So that perhaps when you're sleeping and you're not having sugar in your body, your sugar levels, your insulin is low down and the liver keeps making sugar sufficient to feed all the cells in your brain, et cetera, for normal bodily function.

7:08So insulin is a master regulator in all of us for our sugar levels. And thank you, Naveed. It's really, really clear, I think. So you've got this sort of insulin keeping things level. I guess the obvious question is, why doesn't our body just let all the sugar hang around in our blood? You know, like the fridge, you just keep putting more stuff in it. And then, you know, my brain or whatever else could take the sugar out when they want it why is it why can't i just let it get higher and higher yeah i know that's a brilliant question so when if you think about sugar if you spill sugar particularly in the context of water it becomes very sticky when sugar becomes levels become very high in the blood it starts to stick to lots of our bodily proteins and changes their function makes them abnormal so for example some of the damage that happens in the eye is because the sugar at very high level starts to stick to lots of proteins that are relevant to aspects of our eye function and disrupts it and you lead to what's known as retinopathy, a damage to the eyes.

8:06The same thing happens in the kidneys. The same things happens to some of the bodily parts, proteins that are relevant to nerve function. So sugar levels, when they're high, effectively disrupts lots of raw materials and proteins in our body and disrupts, therefore, lots of normal function and causes damage. I think that's both very clear and very, it's quite scary, this analogy with like the sugar on the table sticky. I can see that that's not what you want sort of coursing through your blood. It's a process partly called glycation and effectively changes the structure of your molecules from what's normal to abnormal.

8:44And then that means it's almost, if I think about it, it's, you know, if you're building a house and you start to make bricks and they're the wrong shape, that building is going to be disrupted and will potentially not have the same level of integrity and will be disrupted and fall apart. That's effectively what's happening inside your eyes, your kidneys, your nerve cells. If your sugar levels are high, you're changing the structure of proteins so they no longer do what's healthy and you're building up tissues in an abnormal way that leads to disease. I like to do a little drum roll when announcing something exciting at Zoe.

9:19And that really exciting thing is that our plant-based gut supplement, Daily 30, is now available in the US. Daily 30 sold out in the UK when it launched, and now we're expecting it to sell out in the US too. And I think I know why, because I use it every day. I love it on my morning yogurt. Not only does it taste delicious, it actually gives me over 30 plants and plenty of fiber without my having to pop a tasteless probiotic or swirl some suspicious green powder into my water. You know what I'm talking about. Also, unlike so many other supplements, Daily 30 actually delivers. Gut health, digestion, energy.

10:00Daily 30's ingredients are designed to improve how you feel, and I feel it daily. Since I started taking it, I've noticed that I often don't need my mid-morning snack, and I feel like I have more energy to take on my busy schedule, and I thought I was doing a good job of eating well beforehand. Of course, I'm just one person, and I work at Zoe. However, because we're Zoe, we ran a randomized controlled trial as we developed Daily30, and the results blew us away, and they helped us to create the gut supplement we sell today, one that's being constantly refined based on the latest research by the scientists that you often hear talk on this podcast.

10:38Oh, and if yogurt's not your thing, I know lots of people who tell me that Daily 30 tastes delicious on eggs, on salads, hummus. My wife likes it on pasta. Many Zoe members tell us it's great on avocado toast too. To get it, head to Zoe.com, where right now listeners to the podcast can get 10 % off by applying the code FEEDYOURGUT at checkout. That's Zoe.com with the code FEEDYOURGUT at checkout. You could be one of the first in the US to try the gut supplement that's changed my day, and I know it'll change yours too. Thank you so much, Naveed. I think that's both a bit scary, but also really clear.

11:18Could you explain then what happens when someone gets pre-diabetes or type 2 diabetes? What does that actually mean? Yeah, this is a question that's often happened. People living with pre-diabetes do have a higher risk of obviously developing diabetes. They don't inevitably develop diabetes. So the term pre-diabetes doesn't mean that it's always inevitable. People who have pre-diabetes, some stay in that level for years. Others can actually go back to normal levels of sugar if they improve their lifestyle. But if you do have pre-diabetes, your risk of developing diabetes is clearly higher. Equally, your risk of heart disease is about double compared to people who have normal sugar levels, don't have prediabetes, have healthy levels of glucose.

12:04I just want to make sure I've got that. You're saying that if you have prediabetes, your risk of heart disease is actually double the level if you don't have prediabetes. Roughly speaking. But here's the rub. At the level of prediabetes, that risk is not necessarily caused by sugar levels because they're not at the level of diabetes. what is caused by is the processes that have led you to develop pre-diabetes in the first place so for example for me to develop pre-diabetes I would probably need to put another four or five kilograms of weight on that excess weight will also mean my blood pressure will go up it will also mean my blood fats and my cholesterol levels will be disrupted so then I will have higher weight higher blood pressure, more abnormal toxic levels of lipids, and possibly also other changes.

12:53And those are the things that cause my higher risk of heart disease. They will also, in a sense, they're stressing my sugar levels. I'm able to keep them still within the non-diabetes range, but they're being stressed because I put fat in the wrong places in my body. And Naveed, I just want to make sure that we all understand what pre-diabetes and diabetes is. And then I'd love to understand more the way these are linked. So what does it mean for someone to have pre-diabetes or type 2 diabetes? And how is that linked to their blood sugar that we were talking about a minute ago? So let me explain it in the terms of a hemoglobin A1c level, which is a common test that we use that gives us an average sugar level for an individual over three months.

13:39So our normal hemoglobin A1C in the UK, it doesn't really matter about the units, is 41 millimoles per mole or under. Hopefully you and I sitting here have got levels of, I don't know, somewhere between 32 and 41. Prediabetes within UK and Europe is between 42 and 47. Diabetes is when you get to 48 and above. And in America, pre-diabetes criteria is a bit wider than we use in the UK. It's from 39 to 47, which is probably why the category perhaps of 100 million, I don't think is quite as high as that. There's always some interpretation based on CDC data that they have to extrapolate and base, you know, just a few caveats.

14:28But nevertheless, that's what it is. In older hemoglobin A1 terms, the levels we had in our mind was diabetes is at 6.5%. We use the percentage. pre-diabetes is from 6 to 6.4 in the UK or from 5.7 to 6.4 in the US. And effectively, that's hemoglobin A1c and it's capturing your average sugar levels, your average exposure to sugar levels for three months. So it's a very good stable measure that we measure in the clinic all the time. Increasingly, it's used to diagnose diabetes or diagnose pre-diabetes. And I've heard doctors often refer to this as HbA1c, is that right? HbA1c, hemoglobin A1c. And so the way I understand, I just want to make sure I'm playing it back right.

15:10The way I understand it is, you know, your blood sugar is changing all the time. So you ate that banana right now and your blood sugar is probably starting to like shoot up. Then you'll put in the insulin you describe and it'll come back down. And this HbA1c is sort of like this average measure of your blood sugar, like a sort of like something on the tank on the car that's just telling you like what the average is over like months rather than this thing that's changing all the time. Is that? That's perfectly correct. So if I'm able to, after my banana, keep my sugar levels from going too high and keep them within the normal range, and every time I eat food, if I keep it relative within the normal range, my HbA1c will stay within the normal range because on average, my sugar levels are high.

15:54I've been kept normal. Amazing. And so to make sure that I, I just want to make sure that I've got this. You're sort of saying we all have like a level of sugar that we would normally have in our blood. we can measure it with this HbA1c. And if somebody has been diagnosed, is listening to this with pre-diabetes or type 2 diabetes, this is higher than it should be. And this is the concern. And we'll then talk a bit more about what it means and what you might be able to do about it. That's broadly correct. I mean, and the reason I think I'm, you know, clearly, we can measure sugar levels they can also give us an indication you know particularly when you're fasting that you know we think the sugar level should be below seven millimoles per liters we can do it fasting but the move in certainly in the uk and also in the us and many other countries in the world to diagnose diabetes they've increasingly started using hb hb a1c because of its stability because it doesn't need to be done fasting because it can also be measured when people have infections or admitted to hospital because none of those things are going to change on average for three months.

17:05So it's a very good aggregated marker. Now, it's not perfect all the time. There are some circumstances like people who have very severe anemia or they have a certain different type of hemoglobin, so-called hemoglobinopathy. You know, we have to be slightly careful, but that's a very, very small percentage of the population. So therefore, the vast majority of circumstances, HbA1c is a very good aggregated measure of sugar exposure that your body has been exposed to and gives us an indication of whether you have pre-diabetes, diabetes, or in the normal range. So I think the obvious follow-on question is, why has there been this enormous explosion in people with diabetes and pre-diabetes?

17:46The team was sharing, again, some of these stats, and apparently there's a sort of four-fold increase in the number of people with diabetes around the world to like hundreds and hundreds of millions of people. And I know that when we look at our own data of people doing the ZOE study of who's there's hundreds of thousands, you just see this, you see, there's lots of people whose levels are far, far lower than the levels you're describing of people with diabetes. So clearly, you know, there's a big shift, I guess, from where I think about like my children, I don't know whether HbA1c is, but I'm pretty confident and it's a long way below these levels, right?

18:19They aren't there. So what's going on? What is causing what I think we could sort of describe as an epidemic of type 2 diabetes with all the scary implications you're describing? And why is it like so much more common now, like even when I was a child growing up? Okay, so I think that's, you know, it's obviously a brilliant question. I'm sure many of the listeners can work out some of the major causes. And one of them, of course, is rising levels of weight and waist girths in society. Because as you put on more weight, as people put on more weight, and as average body mass index levels or whatever waist circumference levels have risen in the communities, that means more people have got to the point where they can no longer store fat peripherally.

19:07and that excess fat gets deposited into some of the key organs in the body that are exquisitely sensitive to too much fat and are relevant to how well you either make or store sugar. And if you put too much fat in some of these organs, you will disrupt their ability to control sugar levels. So for example, too much fat in the liver means that it will continue to make excess sugar in excess of the body's needs when you don't need it. Too much fat in muscles means that your body will not take up the sugar in response to insulin as well as it normally would do if your fat levels and the muscles were less.

19:45That's a simple example. So weight gain is one of them. Another key factor, it's actually linked to success in part. Another risk factor for diabetes is actually living longer, older. So as life expectancies have gone up and more and more people are living longer, we get more diabetes. And part of that reason happens is that in my simple mind, there's three things that determine diabetes risk. The weight you reach and how much fat you put in your organs, your muscle mass, because that's your engine to burn up sugar, and how well your pancreas works. Now, two of those three things, probably all three things, change with age.

20:23As we age, our muscle mass goes down. Our pancreas becomes less, which is the organ that makes insulin, becomes less plastic, as it were, i.e. its capacity to make more insulin to keep the sugar levels down becomes less over time. And also with age, we tend to put on more weight in our stomachs and we tend to lose fat from our peripheries and our arms and legs and peripheral reasons. So with people living longer, we're also increasing the likelihood of diabetes. And that's not just in high-income countries. If you think about all the millions of people, billions in fact, in low-income countries as they've improved their hygiene gradually industrialization, people are no longer dying in their 30s and 40s.

21:09They're living to the 40s and 50s. So they're able to develop diabetes in their 50s and 60s when they didn't because they died with infection or something else. So there's multiple reasons, but to weight gain, increased life expectancy are probably the two major ones. And so, Naveed, I just want to unpack that and make sure that I've understood it and our listeners have understood it fully. So maybe to start with the first one, I think you said something really interesting, which is it's about rising levels of weight in particular places. So it's not just generically whether someone has put on weight, you're saying it's about the fact that that weight is actually being stored.

21:48And so that fat is actually being stored inside crucial organs in our body. And that that is really what starts to trigger the diabetes. Did I understand that right? Yes, that's so-called ectopic fat, fat where it normally isn't supposed to be in any sort of high level. So as an example, all of our liver fat levels should be below 5%. Ideally, usually, if you look at the normal range, under 2%. But when the liver accumulates more fat because your body has been unable to store the fat in other areas because your weight's got to such a level, the body's looking for other places so that excess fat one of which then tends to be the liver as the liver fat levels go up that disrupts the liver's ability to regulate sugar levels normally and the liver actually starts to make excess sugar beyond the body's needs which then keeps the sugar levels high so that's one of the examples so ectopic fat it's not the only cause some people also have shall we say pancreases which make insulin which are unable to make as much insulin as perhaps a healthy individual so that for even when they're not very overweight their pancreas pancreas's ability to make insulin becomes diminished with age very quickly and then and it's a pancreatic driven type to diabetes but even there if you know genetically if you can't make as much insulin as the other person, it's still usually weight gain that's the trigger for diabetes.

23:20And people then tend to have to put on less weight to get that diabetes. So there's an interaction between how well your pancreas can make insulin, how much fat you put in the wrong organs, and how good is your muscle mass. I'm sorry, Naveed, can I just, just before we jump on, because I think the weight in your organs affecting the way that they work, that makes sense. And you're describing the pancreas as one of those examples. It's so important, it's making the insulin. Could you just explain the muscle mass for a minute? Why does the muscle mass have any impact on diabetes? Muscle mass is often a measure of how active you are.

23:56So activity plus, as an example, my muscle mass used to be not so good. It's actually probably a bit better and I've got a dog and a psycho and so on. Congratulations. That's great. Well, you know, and my HDL has gone up and I can see it. I can see it as a biomarker. It's gone up, you know, really almost doubled. Which is a good thing. Which is a very good thing because I do have a family history. So I think my pancreas, probably genetically being South Asian family history, it's got a lower reserve to keep making insulin to the levels I need to overcome, you know, any resistance in my tissues, as it were.

24:33So by building up muscle and being more active, I have an engine that burns sugar more. So that means I've got an engine that can burn sugar. That means that sugar is not going to stay as high, if that makes sense. Also will burn fat as well. So by having more muscle, so it's actually going to pull the sugar out of my blood, it's going to burn it up. So that's like, it's improving everything. And if I don't have that, I'm more likely to store it in my liver and my pancreas. Exactly. It's like having a very efficient engine and a bigger engine for the amount of fuel. If you overpack the car with fuel, you know, too much oil, the oil will disrupt the engine.

25:14You know, and if you keep the engine clean and bigger, it may be able to cope with more oil. It's that, you know, it's that kind of simple analogy. And can I follow up on the point about the differences between people? Because I'm really interested in that. And you were just talking about being South Asian heritage, and I'd love to understand a bit more about that. But the other thing I was interested in is sort of difference between men and women, because I know that when we've had other conversations to do with other risk factors, we've had this conversation about women, particularly before menopause, sort of storing fat in different places.

25:48And is there a difference between men and women in terms of their risks of diabetes as well? else I'm really curious about for people listening how these things might be different pertaining to them on who they are yeah well let's explain all those risks in the prism of where you store the fat so women generally have a much greater subcutaneous you know so they're able to store fat peripherally thighs legs and obviously you know the shape of women is such that you know they have other stores of fat shall we say so women generally in a sense have a greater storage capacity for fat in the peripheral area that means they have to put on more weight overall before that fat starts to seep into the liver and peripheral just to make sure basically because for anybody who's not seen the video where navid is helping to indicate you're basically saying everywhere that's not sort of in my torso and around my exactly my belly that women can store a lot more fat there and part of the reason women have to store more fat is partly because women have children they have to feed the children they have to breastfeed they have to supply nutrients to the child you know one of the things that happens in pregnancy is the placenta can suck lots of nutrients for mom so if mom you know if and if mom doesn't have enough fat storage they can't often get pregnant you see that in athletes so you like need like your body is like you know talk about like evolution over millions of years not like necessarily doesn't mean you as a person listening to this have to get pregnant at the point is that's how like our bodies have evolved Yeah, that's exactly right.

27:20So if you compare men and women in terms of how much fat they have in their liver, even in healthy levels, men tend to have higher levels of fat within their liver compared to women. And also men, when they generally put on weight, it usually is accompanied by their waist circumference going up straight away because they tend to store it. You know, they're all closer already to the threshold of fat going into the wrong places. So with a little weight gain, men's fat usually goes into the wrong places. Women, however, generally can put more fat in peripheral regions into the thighs and other areas before it goes into the more harmful places like the liver and muscle, as it were.

28:02So that explains why men in every ethnic group are at a higher risk of diabetes than women for type 2 diabetes. It probably also explains in part why men are at higher risk of heart disease than women in all ethnicities by and large. and with that same prism if you compare you and i jonathan uh you're you know you're sitting there you know you're caucasian or white i'm south asian we know that south asians on average have 10 on average lower muscle mass and carry more fat mass already and i we also have higher levels of liver fat even when we're healthy so me compared to you i've got higher liver fat so i'm closer to where I'm going to put too much fat in my liver sufficient to develop diabetes than you are.

28:47You are closer than the average, you know, say an age comparable woman. So that explains the men versus women risk. It also explains the whites versus non-whites. And every non-white individual compared to whites are at higher diabetes risk. One of the reasons is where people put their fat. It's not the only other reason. Blacks, I think there's another mechanism we don't fully understand. And it's maybe to do with how well your pancreas can make insulin. But certainly for South Asians, in a sense, our body makeup is such that we are, for less weight gain, we will start putting fat into the wrong places.