ZOE Science & Nutrition - How to lower blood pressure, improve heart health and reduce dementia risk | Prof. Tim Spector

Episode Date: June 26, 2025

What if your blood pressure — even just a little too high — is quietly damaging your brain? What if it’s increasing your risk of a heart attack or stroke, without you ever feeling a thing? In this episode, Professor Tim Spector reveals why blood pressure is one of the most overlooked – and most dangerous – health issues today. He explains why “normal for your age” might not be safe at all, why medication alone isn’t the full answer, and how small, daily changes could dramatically reduce your risk of serious disease. Can your gut microbes raise your blood pressure? Can a banana be as powerful as a pill? Is beetroot juice really three times more effective than cutting salt? You’ll also learn why 80% of the salt we eat isn’t from the shaker, how stress and sleep secretly push your pressure up, and what most doctors still miss when treating hypertension. If you’ve ever been told your blood pressure’s “fine” — or never measured it at all — this episode might change the way you think about your future health. 🥑 Make smarter food choices. Become a member at zoe.com - 10% off with code PODCAST 🌱 Try our new plant based wholefood supplement - Daily 30+ Follow ZOE on Instagram. Timecodes 00:00 Introduction 03:29 What actually is high blood pressure? 05:57 Why everyone should own a blood pressure monitor 07:01 What your blood pressure reading really means 09:59 Stress and high blood pressure 11:28 The $20 gadget that can save your life 13:17 When to see a doctor 14:35 What causes high blood pressure 16:57 Salt and blood pressure 18:28 Why reducing salt didn’t work for Tim 20:09 Blood pressure medications 22:04 Why high blood pressure is so dangerous 24:20 How blood pressure quietly damages your brain 27:18 Is it too late to lower your blood pressure? 31:31 How your gut microbes affect blood pressure 34:14 Why potassium matters more than salt 36:29 How sleep, stress & saunas impact your blood pressure 38:58 The real source of excess salt in your diet 41:37 Should you switch to potassium salt? 49:30 Beetroot juice: better than salt restriction? 📚Books by our ZOE Scientists The Food For Life Cookbook Every Body Should Know This by Dr Federica Amati Food For Life by Prof. Tim Spector Free resources from ZOE Live Healthier: Top 10 Tips From ZOE Science & Nutrition Gut Guide - For a Healthier Microbiome in Weeks  Studies referenced in today's episode: Nonpharmacologic Interventions for Reducing Blood Pressure in Adults With Prehigh blood pressure to Established high blood pressure, Journal of the American Heart Association (2020) Long-Term Effect of Intensive vs Standard Blood Pressure Control on Mild Cognitive Impairment and Probable Dementia in SPRINT, Neurology (2025) Blood pressure reduction and all-cause dementia in people with uncontrolled high blood pressure: an open-label, blinded-endpoint, cluster-randomized trial, Nature Medicine (2025) high blood pressure Associated With Hearing Loss and Tinnitus Among Hypertensive Adults at a Tertiary Hospital in South Africa, Frontiers in Neurology (2022) Have feedback or a topic you'd like us to cover? Let us know here. Episode transcripts are available here.

Welcome to ZOE Science and Nutrition, where world-leading scientists explain how their research can improve your health. High blood pressure already affects millions, and the number of cases is accelerating. Sometimes referred to as the silent killer, due to its hidden symptoms. Its link to heart disease, stroke and kidney disease are well established. Now new research reveals it could be linked to many more conditions than we thought. Tinnitus, eye problems, diabetes, potentially even dementia. The good news? Your diet and lifestyle choices might be the most powerful way to lower blood pressure naturally.

In this episode, Tim Spector reveals exactly what to eat to manage high blood pressure, along with surprising lifestyle changes from sauna use to mindfulness that could make a difference. Tim is one of the world's top 100 most cited scientists, a professor of epidemiology at King's College London, and my scientific co-founder here at ZOE. He was also part of a groundbreaking study exploring the connection between high blood pressure and the gut microbiome.

You'll leave this episode with a deeper understanding of the impact of high blood pressure and practical tips to lower your blood pressure naturally. Tim, thank you for joining me today. A pleasure as always, Jonathan. So we're going to jump straight into the quickfire questions from our listeners. Is having high blood pressure dangerous? Absolutely.

Can high blood pressure increase your risk of dementia? It can. Does reducing salt lower your blood pressure increase your risk of dementia? It can. Does reducing salt lower your blood pressure? Yes. Can you lower high blood pressure through mindfulness? You can. Is it true that drinking beetroot juice can help with high blood pressure? Yes. I've never managed to get that many yeses from you, Tim.

Lastly, what's the most misunderstood thing about high blood pressure? Yes. I've never managed to get that many yeses from you Tim. Lastly, what's the most misunderstood thing about high blood pressure? That you can feel it. That you know if your blood pressure is high and people say, oh, I'm angry, therefore my blood pressure is going up, I know how I'm feeling. But you can't, it's a silent killer and everyone needs to know what their blood pressure is, and that can dramatically lengthen their lives. Amazing, so the team actually did some research

for us before the show, and I had no idea how common it was to have high blood pressure. So apparently around half of adults in the US have the condition, and about a third in the UK. I have two close family members with high blood pressure and in both cases that's something that started as they entered their 60s.

It wasn't something that the doctors said to them before but it sort of started about then. I also have to admit, I have absolutely no idea what high blood pressure actually is. So what is it? It is basically a hardening of the arteries and thickening of the arteries so they're not as flexible. And these are the arteries, the blood vessels that go all around your body from your heart,

pumping blood to every bit of your body, including your brain. And each time your heart beats, there's a change in how much pressure is put into the system. And essentially, it's a change in how much pressure is put into the system. And essentially, it's there to absorb that shock. It's also there to have a system so if you're exercising or you need to run away quickly, your blood pressure can go up in short bursts, and that's normal, and it comes back again quickly. So you want a flexible, mobile system.

And what happens when you have high blood pressure, which is also known as hypertension, is that it stays up. It doesn't just come up and go down. Your resting level is higher. So you've got more resistance to the whole system. It's like your pipes are furring up a bit. They're just not as flexible and bendy. And this puts a strain on the rest of your body so it has to sort of work harder to do things. That's a very simple way of thinking about it. And as you say, it's incredibly common and where we draw the line about it being normal or abnormal is a bit flexible itself. So it could be that

if we wanted to have the perfect blood pressure of say indigenous tribes in Africa, then we would put our thresholds even lower and maybe two thirds of us would be counting as having high blood pressure in the West. And it's considered a metabolic problem as well. So metabolic syndrome, which I think we've talked about in the past, is a combination of clusters of things that we get in the West, where you might get type 2 diabetes, you might get obesity, you get high cholesterol, and part of that, as well as heart disease, is high blood pressure. And they seem to have similar causes and relationships, and they all lead on to one to the other.

So if you've got one, you're more likely to get the others. So your whole body is put into stress and that throws out all kinds of mechanisms. Now, I've got high blood pressure. I got this rather suddenly overnight in about 2011. Most people get it slowly, it comes on slowly. Have you ever measured your blood pressure, Jonathan? I've had doctors measure my blood pressure, but I have never measured it myself. Well now's a chance to do it yourself

so that I've got a blood pressure monitor that is for home use in front of you. Do you just want to slip it on now? Absolutely. On your left arm, roll your sleeve up. Roll my sleeve up just like the collar that you wear when you are you know seeing the doctor. Yeah there's no need now to have to go to your doctor to get your blood pressure measured. This is a device that everybody should have in their home because it's probably the single cheap device that you can do to save the most lives. So if you're on now, you're lined up,

you can press the button that says start, and you just wait for it to slowly inflate. And the idea is you should be resting for a couple of minutes in a nice stress-free scenario, just chatting to a friend. So like a live podcast is the definition of a stress-free... It is. Just chatting to me is so relaxing, isn't it, Jonathan? And so you normally take three readings, throw away the first one because you're stressed, and then you record the second and third ones. And it's something you should probably do

you know, once a week at home to check that you are staying within normal limits. And Tim, this thing is just like ballooned up on my arm until it reached the point where it feels a bit uncomfortable and now it feels like it's releasing. What's it actually doing right now? It's stressing the system. It's seeing at what point your blood is pumping through the pressure of the cuff. So it knows what pressure it's putting in, it's seeing whether your own pressure is greater than that or equal to that. So it's a relative measure of the pressure. It's been used for ages. It's not recording the exact pressure inside your whole system, but it's an established way of looking

at risk that we base all our treatments on. So what's it telling you? Let me show you the thing that's appeared up on the screen. Okay, so that's 118 over 78. That means your systolic blood pressure is 118 and your diastolic, which is the low level, is 78. So what does that mean? Why have I got two numbers for my blood pressure? This is just the way it's classically been done. It's the high pressure one and the low pressure one. And at the moment, we record both of these,

but the science changes every few years about which they think is most important. We currently think that the top level is the important one, that's the systolic level, and yours is below 120, which means it's normal. Oh, I passed. You have passed, Jonathan, yes. You actually, on this, you're healthier than me, right?

Okay, so my latest- So that's a win and I will take that. Yeah, absolutely. That doesn't happen very often. So I'm pleased. Normally I do these tests and they're like, oh, your blood sugar control is terrible. Or I look at all that fat you got in your liver. So I'm quite pleased if I've actually passed a test. Yeah, you look very pleased. And do you think if I wasn't in a podcast and you just sort of, I just done this sitting calm in the sun, would it have been any lower? Or is that whole

thing about stress and blood pressure, like not really real? Stress and blood pressure is real in a short-term scenario so short-term stress will put your blood pressure up but it's it's not the main reason that people have long-term high blood pressure. There are many reasons it is one of them but it's normally things like it is one of them, but it's normally things like being overweight, having too much central obesity, having type 2 diabetes, having a poor diet, not exercising. It can be due to stressful scenarios as well, but in fact it's similar risk factors to having a heart attack or having type 2 diabetes. These metabolic risk factors seem to be the major ones. And it has only a small genetic component, so you can't blame your parents generally for your blood pressure. Now I've got a blood

pressure monitor on me that looks like a wristwatch. these new devices that measures my blood pressure automatically every 30 minutes it goes off. And just by reflecting light against my blood vessels, it gets an idea of what my blood pressure is. Tim, for people who can't see it on video, I mean, it just looks like a little small wristwatch, little wristwatch or like an old little Fitbit with nothing visible on it, just a band. That is not inflating like a balloon every 30 minutes and cutting off the blood supply to your hand? No, it's not. And it's using little light emission devices that send light against my skin and against my blood vessels. It bounces back and it can tell the velocity of the wave

and the height of the wave in the blood vessel. And this has now been correlated really well to blood pressure. So I get a very accurate one just from this. But the advantage of this is that although it's not as accurate as the cuff that you've just done, I'm getting 48 results every day, because it goes off every half an hour. And this is really important because if you're tracking your blood pressure, you want to know not what it does in the best of situations when you're perfectly relaxed sitting down. You want to know, okay, what's happening in the middle of the night, for example. That's when your body should be at its most relaxed. We think that's the most predictive. It's virtually impossible to wake yourself up and not be stressed and take your

blood pressure. So these are really useful for exactly that. And this is new technology and it's going to be in most people's mobile phones very soon just by putting your finger over the lens you can get a result. So this is the technology and I think it's a change in our mentality which is blood pressure is something we should be able to manage ourselves without having to need medical experts in most conditions and not for severe problems but this is something everyone should be doing for themselves. $20 you can get yourself a really good machine and you know exactly what's going on you don't need a health

professional to to guide you and so this is why you know we're talking about blood pressure and all the things you can do about it. Well let's say you do have your own machine. What are you looking out for? You just said to me 118, that's good, but I wouldn't have the faintest idea. So what are you looking for? Well, you're looking to keep it at 120 or below as an average reading for most of the time, it will depend slightly on your age because it creeps up with age. If you are 17, you're listening to this and your blood pressure is 125 or 130,

you shouldn't worry too much. But we should always be trying to get it below 120. And many people will be going to their family doctor and they might be told, don't worry, we did your blood pressure. It's 130 over 90. It's average for your age. don't worry, we did your blood pressure, it's 130 over 90, it's average for your age, don't worry about it. That still means you have an increased risk of stroke and heart attack. And so we shouldn't be as complacent as we've been in the past.

We know that even treating people in these very minor levels of blood pressure is still very useful. And it could be very high. So, you know, the other thing is if you do go, where you do it yourself and you find you're consistently 150, 160 at the top level, you shouldn't be waiting. You should be going to get seeking treatment. So for something like that,

you should go and see your doctor right away. Right away, yes, exactly. So the higher it gets, the more immediate your risk of doing some harm to your body is a heart attack or a stroke. So you're 130, you're saying, you know, your doctor might say it's fine, but you're saying, well, it is having some impact on health. And we're going to talk a bit about what that might be and what you can do. But you're saying if it's at like 150, actually, you just need to go and see your doctor right now. And they will say that's the real cause for concern.

Correct. So why do you get high blood pressure? We don't really know is the honest answer. It's a combination of what we call sort of metabolic insults to the body over a lifetime. It seems to be associated with a Western lifestyle, associated with the Western lifestyle, Western diets, sedentary life, just a part of living really because when you do go to very rural parts of Asia or Africa, see people living in natural environments, their blood pressure is remarkably low. You know, we're talking systolic blood pressure less than 100. So I did well for a typical Westerner in their like 40s or 50s, not for someone who would

be living a... African nomadic lifestyle. You know, with the sort of diet that our ancestors had led and five times more exercise than I'm doing. Correct. If there is a risk, it's pretty minute. And what about salt? Because I was thinking about the other thing that came back to me, I thought about it this morning is, oh, it's all about salt or high blood pressure.

So, you know, I'm thinking myself as a CEO, having, you know, salt on my chips. That's basically it. Is it all salt? For many years, we thought it was mainly salt and lots of studies have shown there's a correlation between the amount of salt intake in a population and their blood pressure and then when people shifted around to low salt countries they got less blood pressure but it's as always in science and medicine it's more complicated than that and it does appear that some people are more salt sensitive than others which means that

salt is more important in their bodies than others and for other people other factors are more important than salt. And the evidence so far suggests that in Western populations perhaps about one in four people are really quite sensitive to salt so that a small change in the amount of salt they're having you know whether having it on their on their french fries or their potato chips or adding it to their food makes a really big difference their blood pressure so that if they cut it out

makes a really big difference their blood pressure so that if they cut it out and they go from having I think the US is around two two and a half spoons of salt per day if you cut that right back to what the American Heart Association says you know is less than one spoon to like half a spoon you can get a quite a big reduction in your blood pressure. But the other 75% of the population when they do that, they're only getting like a one to one and a half percent difference in your blood pressure. So for you with 118, you'd only get to 116 if you really restricted your salt intake to just half a teaspoon a day, which might mean that your chips would taste terrible and your steak would be nearly inedible.

And so you've been making a fairly major sacrifice. So the latest science is really changing the way we think about this. And then there are also genetic differences. So if you have someone of African origin, an Afro-Caribbean or African-American, you're much more likely to be salt sensitive. So it could be well over the majority of those populations are going to see quite a big improvement if they cut back on salt.

This is due to some hormones that control the kidney, something called renin that has a big effect. I tested myself, so when I had my initial incident where I had my mini stroke, it turned out that increased my blood pressure over the space of a few weeks. I did try for a month going on assault restriction and it made virtually no difference to my blood pressure.

I was taking it every day with a monitor like the one I've shown you and it may vary a little bit. So I'm clearly not myself salt sensitive and other things are more important for me, but for someone else it could be really, really important. So there's really important personalisation going on here between these treatments. And in the past we've assumed that we should give the same advice to everybody and some people even got worse when they salt restricted. So if you had some type 2 diabetes and you went on too much salt restriction it could actually get worse and your kidney function might get worse. So I think we're still trying to find the right balance here in terms of advising

populations and advising individuals. But it sounds like it's definitely not all about the salt. Definitely not all about the salt. Are people often prescribed medicine when they're diagnosed with high blood pressure? They are, and they're very effective. If you take them regularly, and most people, unfortunately, are not very good at taking them regularly, that's perhaps one of the commonest causes of failed treatments is people just don't think they need to take them every day. A combination of those diuretic tablets, which mean that you pee out more of your fluids

so you're more concentrated. There's calcium channel blockers, which are the other ones, things like Amlodipine are very common. They change the way the vessel dilates because that uses these calcium channels. There's other ones called ACE inhibitors. There's a whole four or five classes of these. They're all effective for different people. And again, different drugs, we did a big study of this and there's quite a big difference between different ethnic groups do better on some than others. You may have also heard of beta blockers which are used to sort of reduce your pulse rate and calm you down. They work very well in some people but not in others. So finding the one that suits you is really important

and again we know the medicines are also personalised just as much as the dietary advice is personalized. So they do work, you've got to take them and you've got to be really fastidious about not forgetting. And are there any risks or side effects associated with medication? All medications come with some risks, but these are generally well managed. If you've got very high blood pressure

and you're taking lots of medications, sometimes in certain situations you might drop your blood pressure and you might be prone to fainting, collapsing, which can cause injury. That's one of the commonest things. Beta blockers can cause asthma. They all can cause different levels of problems in your temperature control. You can may have cold fingers. All these kinds of things can happen, but the advantage is far away. Any disadvantages of the drugs. So there's absolutely no reason to not at least try drugs and see how you get on with them. See if they control the blood pressure quickly and ideally without any side effects,

because the risks, if you don't are huge. Your risks of having a catastrophic stroke or a heart attack are increased exponentially for each just millimeter of your blood pressure going up and how well you can control it. What are the disease risks that you face if you are living with this high blood pressure? Sounds like you said you described as a silent killer, so very possibly not even realizing it.

What might happen? The classical ones are increasing by threefold your risk of a heart attack, which can come out of nowhere. Your blood vessels and your heart are put under strain and that leads to a blockage and you get a heart attack. Having a stroke is also you get, you know, three to five times increased risk of a stroke. So these are really big increases, you're talking three times higher. They're not trivial. Yeah, they're not trivial. It also, all of these depends on how, what your level of blood pressure is.

The higher it is, the higher the risk. Because we define someone as having high blood pressure, currently is anything over 130, over 90. But there's a whole range above it and just below it in that gray area we talked about. And are you able to explain in simple terms why my having this high blood pressure increases so massively those risks of sort of heart attacks and strokes?

We don't know the precise details of those organs are under strain and stress. Because as I said, if your blood pressure is high, that means also that you develop increased rigidity of the less flexibility of your blood vessels. So they can't respond easily to any stresses in the system as much as they would, they can't cushion it. Because in a way we're often repairing our own blood vessels

all the time as the blood is flowing through it. And if you've got these stiff, rather rigid ones, instead they can't do as good a job at repair so they more easily get blocked, more easily get inflamed, and inflammation then attracts clots and other things to it. In your brain, the blood vessels can either form a clot or they can actually bleed, so they can get like a little stress in the blood vessel and you get a hemorrhagic stroke. And we also know that it's also related to a whole range of other metabolic conditions.

So dementia is something we mentioned at the beginning. People often think of dementia as purely as Alzheimer's disease, but at least a third of dementia is related to the blood vessel disease. So the bits of the brain are not getting the same level of energy intake nutrition they would get because of the state of your blood vessels because of this constant pressure they're under due to the high blood pressure. And so Tim, just to make sure I've got this, it's not just it can create that like sudden catastrophic heart attack or stroke as a result of this pressure being so high.

There's also like a slow long-term impact. You're describing something like dementia, which I think I know from some of these other podcasts, it doesn't just happen in one day. It sort of happens over time and the blood pressure is sort of causing damage over time? Yes so it causes metabolic upset it also cause inflammation and just the body is having to work harder and harder so everything gets less efficient and this is this common theme

we keep talking about and this is why a high blood pressure is part of metabolic syndrome. That yes, if you have type 2 diabetes, you more likely to have high blood pressure, but it also works the other way around as well. But if you got this defect in your blood vessels, that causes stress to all your cells and the way they're pumping out

energy and using fuel in all the organs in your body. Makes you more like to have kidney disease, makes you more like to have brain disease in terms of dementia and affects all bits of your body to some extent. So it's not just a sudden yes or no, I'm gonna get a stroke or not. It has a really harmful effect on many aspects of your body. It needs to be seen as a metabolic disease rather than as a purely one-off thing on its own. It's a sign that your body's not healthy. So it's both a sign that your body's not healthy, but it's also a risk factor that can then cause something.

So you were saying it might come from type two diabetes, but it also might be something that causes you to get type two diabetes? Correct. You've mentioned dementia and type two diabetes. Are there any other diseases that we now know are linked to high blood pressure that beyond the stroke and heart attack

that I think was our common sort of knowledge in the past. So as well as kidney disease, you've got eye problems. It's related to macular degeneration of the eye, which is often caused by blood vessels in the eye not being flexible enough, and that gets a common cause of blindness and hearing loss. Again, the microvasculature of the ear is related to that. And it can also cause a really annoying perception problem in the ear called tinnitus,

where you get a low-level buzzing, which is extremely unpleasant to have. So lots of little, both minor and major problems all associated with a failure to really control our blood pressure. So it definitely sounds really serious. It also sounds like lots of people listening on this podcast, when they go and get themselves measured, will discover their blood pressure is higher than they thought it was,

higher than this sort of healthy range. If they then reduce their blood pressure is higher than they thought it was, higher than this sort of healthy range. If they then reduce their blood pressure, is it too late to fix any of the damage? Or if they reduce their blood pressure, does that reduce the risk of all these diseases in the future, even if it's been high in the past? It's never too late to reduce your blood pressure. I think that's generally the case,

apart from people maybe in their hundreds. For most of us, even if you've not known about it for 10 years you'll still get enormous benefit from getting that blood pressure down to that 120 over 80 range where you will start to see the benefits and your metabolism, your body will improve, the inflammation will improve, your risks will suddenly drop of many of these conditions. Some, the inflammation will improve, your risks will suddenly drop of many of these conditions. Some of the damage will be done but you'll still be protecting your future life in a big way if you take action. So I think you have got to be very positive about this and not think

about the past, think about the future and your future years. And especially, you know, I've seen my mother have a stroke. She had poorly controlled blood pressure. And we all know people like that. And it's such a preventable condition that we really all need to be taking much more care of our blood pressure. So if you don't mind my asking, when you talk about that example with your mother, are you saying that you feel that if she'd managed to control her blood pressure. So if you don't mind my asking when you talk about that example with your mother, are you saying that you feel that if she'd managed to control her blood pressure better, she might not have had that stroke?

I think that's correct, yes. The data show that if your blood pressure is well controlled as opposed to poorly controlled, it can halve your risk of having a stroke. You can never eliminate the chance completely because sometimes people have stroke without having high blood pressure but you can dramatically improve the odds and I think you know she used to wait and go and see her GP every couple of months and get a blood pressure check but you know she didn't have the technology we've got now where we can do this every day ourselves.

And we know how important it is to take the tablets at the right time. In a way, fine tuning your medication to the blood pressure is really important. And how the new insights we've got about trying to work out what your blood pressure is like at night when you're in your supposedly totally relaxed state. We can optimize things now in a way we couldn't do before. We know much more about it.

It was a very blunt instrument before, you know, and people used to put off seeing their GP because there was a, you know, they couldn't get in. And they say, you go a year later and, you know, their blood pressure is through the roof and some damage has been done. And Tim, the team said, I should ask you about a very unusual study that you were involved in, looking at the relationship between blood pressure and the gut microbiome. Yes, that's right. So about five years ago, we combined my twin cohort from King's, which is a group of thousands of twins we've been looking at for 30 years.

We have very good blood pressure data and we had their gut microbiome readings and we combined that with some Zoe members that we also had reported having high blood pressure and we knew so knew their gut microbiomes put these together and found that people with abnormal gut microbiomes, unhealthy gut microbiomes, nearly always had higher blood pressure than people who had normal microbiomes. So regardless of whether in the US, the UK, twins or not, there was a very consistent message here that the microbiomes were abnormal. We we found certain ones that were high

in people with hypertension, certain microbe species that were affecting some of these renal pathways. So it looks like the chemicals some of our microbes are secreting could be very powerful in protecting or increasing our risk of having hypertension, high blood pressure. Were you surprised by that? Because I have to say, somehow the idea that

your microbiome is affecting your blood pressure, which sounds like something to do with your heart, seems a bit crazy. I was more surprised five years ago than I am now. But now, the ability of the gut microbiome to influence everything in our bodies now doesn't seem to be quite as crazy. We also realize they secrete all kinds of chemicals and our bodies and our kidneys, which control all of our blood pressure, are very sensitive to these chemicals.

And so it now makes perhaps more sense than it did then. And I think we realize that there are lots of pathways going on that we need to control to get the ideal blood pressure for our environment and this is what it's doing and it sort of makes sense that the the gut is in a way but acting as a bit of a sensor for what we're eating and then putting out chemicals to try and do what it thinks is the best way for our body to react to that food and that environment. And it comes back to this idea we're talking about salt is this the only thing? Clearly it's not. The pathways we're seeing weren't just salt pathways and other studies have now shown that as well as salt being important, things like potassium are actually even more important.

Potassium is another key element that is important in how much water goes in and out of a cell. Studies have shown that it's the sodium to potassium ratio that's much more important than just salt on its own. Remember, salt is sodium chloride. So In the US they always talk about sodium levels in the UK We talk about salt levels, but we're essentially talking the same thing and say it looks like from these these trials where they've either observed potassium and

Salt intakes that potassium intake has an even bigger effect than salt Salt intakes that potassium intake has an even bigger effect than salt Potassium is bad for you in the same way the salt is no, it's good for you. So it's acting in the opposite direction So if I want to reverse high blood pressure, I want to increase your potassium intake and You do that classically by giving you some bananas which have a reasonably high potassium intake but also things like kiwi fruit have even more and most green leaf vegetables also have high potassium intake. So people on vegetarian diets, high plant diets are naturally getting a lot of potassium and this is another reason why your holistic diet is perhaps more important than just whether you're getting

a lot of added salt. So Tim, I would love to switch now to that actionable advice, because I think you've painted a picture where you sort of saying like your blood pressure is really important. You should know your blood pressure, reading, if it's high, you need to do something

that it can have really bad impact if you don't. So I expect lots of people listening to this are saying, one, I should go out and buy one of those blood pressure monitors, but number two, what can I do in addition to, or instead of going to the doctor to take a pill? Is there anything that people can do in terms of their lifestyle?

Absolutely, yes. So lifestyle changes, as we've discussed many times, are important. So if you're too sedentary, that's gonna put your blood pressure up. So try and do some exercise. Sedentary is like doctor speak for sitting on the couch and watching TV.

Sitting on your bum all the time, yeah, exactly. Modern lifestyle, working at home, very bad for you. Get out there, do some walking, do some exercise. That's good for blood pressure. Sleeping well is also related to blood pressure, so sort out your sleep as much as you can. That's not just one of these sort of hand wavy things, so your sleep really has an impact on your blood pressure?

Yes, it does. And again, we see this repeated because blood pressure is part of this metabolic group of conditions that all seem to have similar causes. A poor night's sleep or doing lots of shift work will actually raise your blood pressure. So particularly if you are doing night work, shift work, you are more prone to these problems. So it is a risk factor. Generally, we did sort of laugh off stress, but if you've got chronic stress in your life,

then that is associated with blood pressure in many studies. And try and find ways of reducing that through something you enjoy, whether it's sport, or it can be something like yoga, it can be like meditation, it can be something like yoga. It can be like meditation. It can be Through having sauna there have been some small studies showing that people who have regular saunas do have lower blood pressures so

anything that and it sort of makes sense because you're Expanding and you're stretching your your blood vessels when you're going for a sauna. They're trying to keep up and keep your temperature constant. So they're having a little workout. So this is like the gym for my blood vessels is just to sit in a sauna and sweat. Correct. Yes, exactly. I love that. It's definitely less painful than the ice baths.

We know that that's not my thing. I know you prefer sauna to ice baths. But the same way mindfulness and yoga, they do relax you and you will get some benefit from that as well. But I think the main thing we should focus on, everyone can do is to think what in their diet can they do to get their blood pressure down because every millimeter counts.

So can we talk a bit more, can we start to dive into diet then? Maybe start with what might be causing the problem. What in my diet might be raising my blood pressure? These would be most likely be processed foods that have high salt content. We think that about 85% of the salt you get in the average American or British diet comes from pre-packaged, manufactured, highly processed foods. So almost all the salt does not come from when you pour salt onto your meal?

Unless you live and work in a French restaurant, then it's only about 10% of your intake. It varies a bit, but it's at most 20%. So at least 80% is coming from pre-packaged foods that you're buying, whether in canned soups, whether they're in biscuits, they're in muesli, they're in children's cereals, things that you don't expect to find so much salt. And is that more salt than we would have put in our diet,

you know, in the past when people would have just been cooking their own versions of these meals? Much more, yeah. It's like three or four times more you were getting. And they're often doing it to disguise some of the other flavors. Salt is used to disguise a lot of the chemicals that they're putting into these foods. It's also provide this hyper palatable it is a term we talked about make you overeat. Say bike adding a certain amount of salt to things you combine that with salt and fat in these foods you will naturally overeat and therefore spend more money on that company's product than you would otherwise have done. It's used. So this is like a big part of what sort of big food

is putting into these meals, either to hide like the ingredients that you might taste and don't taste as nice, or just to make you have that thing where you just can't stop eating and it's sort of that sort of magic point where it's so delicious that you're just gonna eat the whole pack.

Correct, and it's obviously so vital to their product they really haven't worked out a way of doing without it and so it's the number one thing that we should be avoiding and it's the worst thing is it's in many you know children's products and things you don't even think are salty I mean don't normally think of cookies or biscuits as needing salt in them and yet there they are with the sugar you've got the salt. It's often used to preserve them for even longer shelf lives as well so that's where most of the salt comes from and I don't think there's any harm in telling everybody who's worried about their blood

pressure to avoid those kinds of foods because even if it doesn't dramatically reduce your blood pressure, if you're not particularly salt sensitive, you get so much other benefits from not having those kinds of foods anyway. So I think everyone should be doing that. The second thing you can do is if you do find yourself adding a lot of table salt to your food, you're someone who likes that, you might want to switch to a different type of salt called potassium chloride. So this is sometimes labeled as low salt alternatives. So salt has the chemical formula sodium chloride, and these low salts

are potassium chloride, and they basically mix the sodium chloride with potassium chloride to give you a similar taste but much less of the sodium, more of the potassium. And when they've done clinical, randomized clinical trials of this, they show that if you switch this around and you're not having all the other sort of junk foods we talked about, you can reduce your blood pressure by about 3 to 4 percent.

So more than just producing salt on its own. So that's a pretty good tip. The only problem is for many people they have a rather metallic taste and they don't like it. But this is what manufacturers should be doing. They should be putting much more potassium than sodium into these pre-packaged foods. That would really help them make them less harmful for us. The other big thing is is realizing that just by increasing your potassium level you will be improving your blood pressure, you'll be

reducing it. And the best way to improve your potassium level is to eat more varied plants. I'm not into superfoods, I don't think people should be eating tons of kiwi fruit necessarily, but that's a good example of one that is full of potassium, but fruits and vegetables in their natural form are fantastic sources of potassium that we should all be eating more of and less salty things and just change that ratio. And the more you do that, the more you'll be able to improve your blood pressure naturally, even before you're going onto blood pressure medications.

And they can also enhance blood pressure medication. So it's not either or. I think even if you're on a blood pressure medication, the more you can help it with diet, the less you need to go onto higher doses or a second one, which could give you more side effects, et cetera, the better you'll be. So you feel like combining this with medication makes sense?

This isn't something where just popping the medication sort of solves the problem for everybody? Absolutely, yes. So I think they should be used together. I think we should be seeing diet as another arm of medication, not as a complete alternative, only if you don't believe in medication

because for this particular condition that the evidence is so clear that medication will save your life and will stop you getting a stroke and heart attack so I don't want anyone to think that this is instead of it's's usually in addition to, it might mean that you can eventually, you might be able to get off your medications. If you're someone who started them when they were on a really poor junk food diet, your doctor didn't tell you that that reason was you were getting all these terrible blood pressure inducing effects from the food. You changed that, you've improved your life, you've improved

your gut microbes, they're secreting other chemicals, you might then be able to wean yourself off these drugs. That's possible. You've certainly heard stories of this from people who've written to me. So bear that in mind, but do that under medical supervision. And Tim, is it just reducing your salt and increasing your potassium through certain plants that will reduce blood pressure or is there anything else around diet that can affect your blood pressure? It's quite likely that we haven't proven it yet that improving your gut microbiome generally will also have this effect on reducing blood pressure. So that's why there've been various studies of fiber, for example, showing that if you give people

high fiber diets, generally their blood pressure will drop. We think this is again through the gut microbiome. And there's also studies of probiotics. A number of trials have shown that probiotics, which are these live microbes you can have, can reduce your blood pressure, again, likely through the gut microbiome. And fermented foods as well have been shown in a few small studies, not large ones, again, to have this effect.

So I think a number of mechanisms, you know, reducing salt, increasing potassium, improving your gut health, all of these have been shown to have important effects on your microbiome. So I think you're saying that we know that a diet that's really good for your gut is really good for your overall health. It sounds like you're saying you would expect that to impact blood pressure as well isn't a blood pressure isn't just driven by the sort of sodium and potassium that you've been talking about earlier? Yes it's much more general

it comes back into this idea that it's part of these metabolic diseases so just as you improve your gut health you're going to improve your metabolic health reduce your insulin resistance you're going to perhaps start, reduce your insulin resistance, you're going to perhaps start to reduce your internal fat levels, all these things that have an impact on your body that's also going to help your your blood pressure as well. So you know increasingly we're seeing these very common patterns of disease we thought were very distinct or having common causes and common treatments. Do you know someone who lives with high blood pressure?

Share this episode with them right now, so they can make simple dietary changes that could lower their blood pressure. I know they'll thank you. Listening to all of this and coming into this podcast knowing almost nothing about blood pressure, Tim, I'm struck that you've talked a lot about salt on the one hand

and how like 80% of that is in sort of this highly processed food. And on the other hand, moving to like a really plant rich and diverse and gut healthy diet can really help blood pressure. And I guess that makes me want to ask how big a role is sort of the highly processed food in a packet that we eat today

playing into high blood pressure? And I guess does that mean is high blood pressure, is there more high blood pressure now than there was 50 or 100 years ago? Oh yes, no, definitely our blood pressure has been our average blood pressure has been creeping up every decade since we started doing surveys and measuring it and I think our poor food environment is probably the number one factor in that and as always in nutrition we've tended

to over focus on one element, and that's been salt. And I think we've been blindsided by that because most people who restrict their salt are not going to get very much benefit if that's all they focus on. There'll be, as we said, African origin or one in four people will get a benefit, but most will only get a small benefit if they took a more holistic view and saw that okay what are the other things in the food that are causing these problems indirectly say through the gut microbes or making their metabolic health worse then they'd be much better off because it is clearly correlated with poor diets, poor environments, poor social class, all these other elements that are not just about salt. Final question, because we brought up at the beginning,

you haven't mentioned beetroot juice, but it came up in the questions at the beginning. Beetroot juice is one of those plants that is really interesting and it has a special effect on blood pressure. So they've actually done quite a few studies of giving people beetroot juice and it reduces your blood pressure three times more than salt restriction. Three times more than salt restriction to have beetroot juice. Yes, most of the studies share on average about a four percent reduction in your blood pressure. And this is because it interferes with nitrates in your blood and these have really big effects

on your blood vessels. They were giving people a large glass of beetroot juice, which would be probably a large beetroot a day, which is probably more than most people would normally eat. And is beetroot juice like a sort of concentrated beetroot? Or is that just like, am I getting like more beetroot out of a beetroot juice? Or is it sort of watered down?

I don't, I don't think I've ever had a beetroot juice. I think you just mash it up into a smoothie and then dilute it. Okay. I don't think it matters whether it's the juice or you're actually having fresh beetroot. It's full of really good elements, including it obviously has potassium in it,

but it has these nitrates, which have this very special effect in addition on the blood vessels themselves. So I think it's another reason to include beetroots into your diet, particularly if you do suffer from a high blood pressure, have them in salads. But probably if you're having three times a week,

I imagine you're still getting some benefit from it. No one's done these large studies. And of course, as always, it's gonna vary by individual. Brilliant. So Tim, it's the first time we talked about blood pressures. I'm gonna try and do a quick summary. So the first thing you said is it's a silent killer. You're not actually aware if you have high blood pressure.

It's going up every decade. So this is getting worse and worse. So make sure you get yourself measured. You can get a device for like 20 DAP dollars, 20 pounds. Measure yourself regularly. And even if it turns out that your blood pressure is currently high, actually if you reduce it, you can have a big impact in terms of reducing your risk

of like very serious diseases and death. And in particular, you talked about your own story with your mother having a stroke and the risk of heart attack. Like there's a very serious risk. Diet can have a big impact on this. It's not just medication. If you want to do something fun try beetroot juice if you're thinking a bit more broadly then

Yes, you want to eat more things with potassium and we now understand that that's that's very important But also you want to reduce your salt But it isn't going to be the salt that you're adding into your diet by pouring salt onto a meal Almost I think you said 80% of the salt we now eat is in this highly processed food, generally in the sort of highly processed food that's really bad for us and they're putting it in there to sort of hide all the other chemicals and additives that they put into it. And so it tastes good and it also probably makes you eat this more often.

It's not only, however, diet. You also said like exercise can have a big impact. And for many people who are not really doing any exercise, that shift even to a moderate amount of exercise can have a big impact on blood pressure. Sleep, interestingly, also affects it. And finally, rather to my surprise, you said chronic stress can affect this,

and there is some, you know, sort of limited evidence evidence but you said it's a real evidence that if you can find ways to reduce your stress, sauna, you know maybe even meditation that could potentially also have an impact on on your blood pressure as well. Absolutely yes. Wonderful well we will measure my blood pressure again now at the end of the episode and we'll see whether or not I've managed to lower or raise my concern while being told about all the terrifying things that might happen if my blood pressure went up.

And we can celebrate with a beetroot juice. Let's go and do that. Thank you very much, Tim. Pleasure.