4 things you can do to lower blood pressure with Dr. Sanjay Gupta

High blood pressure is the number one risk factor for deaths globally. But what if your blood pressure numbers were only part of that story?

In this episode, we’re joined by leading cardiologist Dr. Sanjay Gupta, who explains why blood pressure is not a disease, but often a scream for help.

Together with ZOE’s Chief Scientist Prof. Sarah Berry, he explores when blood pressure is a harmless response to stress, food, or movement, and when it signals real, long-term damage. You’ll learn why blood pressure targets aren’t universal, why worrying can make things worse, and why quality of life matters as much as numbers.

If your blood pressure is your body sending a message, what might it be asking you to change?

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Transcript

Jonathan: Sanjay, thank you for joining me today.

Sanjay: Thank you for having me.

Jonathan: And Sarah, thank you for being here.

Sarah: Pleasure.

Jonathan: So, Sanjay, we have a tradition here at ZOE where we always start with a quick-fire round of questions from our listeners, and we have these very strict rules. You can give us a yes or a no, or if you have to, a one-sentence answer. You willing to give it a go?

Sanjay: Yeah.

Jonathan: Alright. Can long-term high blood pressure lead to dementia?

Sanjay: Yes, absolutely.

Sarah: Is low blood pressure always better than high?

Sanjay: No.

Jonathan: Can simple lifestyle changes lower your blood pressure significantly?

Sanjay: Yes.

Sarah: Does alcohol help lower your blood pressure if you're stressed?

Sanjay: It may do.

Jonathan: Can your gut microbiome influence blood pressure?

Sanjay: Absolutely.

Jonathan: And finally, what's the most common misunderstanding about blood pressure?

Sanjay: The idea that blood pressure is a disease. For many people, blood pressure, I believe is a scream. The body is screaming out and saying, I'm unhappy. And if we take the scream and make it a disease, then you end up treating the blood pressure, but not addressing the root cause of the scream. And in some ways, you do that patient in disservice.

Jonathan: I've definitely heard of high blood pressure, and I know that it's one of those things that lots of us are told by our doctors that we should worry about, but I can't be the only person who doesn't really understand what it means, why my blood pressure rises and what it means for my health. So luckily, we have one of the UK's leading cardiologists to help us finally understand what it's all about. And we're joined by Professor Sarah Berry, who, I discovered, actually spent many years running clinical trials in humans looking at the impact of food on blood pressure. So I think we're in for a treat. Can we just start at the beginning, Sanjay? What is blood pressure?

Sanjay: Okay. To understand blood pressure, we have to understand pressure. And pressure is physiologically a formula, which is force over area. You exert some force over an area, and that equates to pressure. If you increase the force, you increase the pressure provided the area remains the same, or if you reduce the area and the force is the same, the pressure goes up. So, blood pressure is the pressure exerted by blood on the area of our blood vessels. So the force is dictated by the heart rate and how much blood is coming out of the heart because the heart is pumping the blood into these blood vessels, and the area is dictated by the radius of our arterioles, our blood vessels.

So blood pressure will vary based on heart rate, how much blood is coming out of the heart, and also the surface area of our arterioles. So it is a constantly changing dynamic variable. It is not something which is static all the time, and this is a common misconception amongst the general public, and blood pressure will go up physiologically. Depending on what you're doing. So if you're moving, your heart rate will go up, your blood pressure will go up. If you are stressed, your blood pressure will go up. If you've had too much salt, your blood pressure will go up. If you're producing stress hormones, they cause our blood vessels to constrict, so your area has gotten less blood, and the blood pressure will go up. That is not a disease; that is just a response to the body.

In response to the things that person is doing, why is blood pressure important? Well, I'd liken it to a little bit like when you're trying to water your plants. You have to have a certain amount of pressure in your hose pipe to get the water to that plant. If you don't have enough of a pressure, the plant doesn't get the water and dies. If you have too much pressure, you damage the plant, and this is exactly how blood pressure works. It has to be within a certain range. If it's too low, then the patient's organs don't get the blood and those organs suffer. And if it's too high, you damage those organs by damaging the blood vessels. And that is why blood pressure is important. So you don't want it to be too low and you don't want it to be too high because you risk damaging the blood vessels. And therefore those blood vessels then heal by clotting off, which means less blood gets through those organs.

Jonathan: And so like during my day. If my heart rate goes up because I'm running to catch the bus. Are you saying that literally because my heart rate has gone up, then suddenly my blood pressure goes up almost sort of in proportion to my heart rate?

Sanjay: Absolutely. And you can see this very starkly when you're watching Olympians, for example. Weightlifters, when they're lifting all this weight above their head, you can see their blood vessels sticking out and their eyes ready to pop out, you know, and we don't see anything bad happen to them. We say, well, this is because they are exerting this amount of effort. It is indirect response to what they're doing. So the point is that our body and our body's blood vessels have the ability over a period of time to cope with certain pressures based on environmental factors, etc. The problem arises when over a period of time, our blood vessels start losing their elasticity. And when our blood vessels start losing their elasticity, they can no longer stretch to accommodate some of that pressure, keeping that pressure down.

And so if the blood vessels cannot stretch because of wear and tear hardening, etc, that's when the blood pressure goes up. So one has to distinguish between, oh, is this just physiological? Is this because I'm just stressed? Is this because I'm just eating the wrong food? Or is there a harmful process going on in my body, which is causing progressive hardening of my blood vessels, which then results in the sustained elevation in blood pressure. I think that in some people the blood pressure is a symptom of something else, and it is probably the lifestyle, the obesity, the bad food, all that kind of thing. That probably causes the blood pressure to be elevated and also contributes to type two diabetes, fatty liver, all that kind of thing. And that probably harms more people than just looking at blood pressure as a single variable.

You know, I think that's really important to say. For example, what happens is a patient goes because they carry too much weight. They're stressed, they're not sleeping, they're eating all the wrong food. They go to their doctor, their blood pressure is up. The doctor says, your blood pressure is up. We need to give you some tablets. The blood pressure goes down. The patient is happy. He's comforted by the fact that those tablets have done the job and he thinks that is no longer a problem. But then you find that his HbA1c starts rising. Then he goes back to the doctor, and again, perhaps the HbA1c going up is another scream from that unhappy body. So I think it's very important that we start realizing that some of these things are symptoms, not conditions of their own accord.

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Jonathan: I'm not understanding the harm yet, so long term, like I understand I don't want to die of a heart attack or I don't want to get dementia. Help me to understand if this blood pressure keeps up high long-term. Like do I care about these little clots in my tiny blood vessels?

Sanjay: Absolutely. Because at the end of the day, if this is happening every day, the amount of blood getting to your vital organs is going to go down substantially. That's how all these things happen. So it's not a case of the blood pressure is not doing anything to your body and suddenly you have a heart attack 10 years down the line and someone says, oh, it's the blood pressure that caused this. Something has to be happening on a microscopic level over a sustained period of time. Then it translates into macroscopic damage stuff that you can see. So dementia isn't a case of you're fine, fine, fine, and then something happens and you develop dementia. It is a progressive, insidious, slow process that's going on in the brain that gets missed because the person looks fine.

You know, on the outside, the person looks fine, they feel fine, but what is going on in their bodies? So if you look at hypertensive patients, for example, patients with true high blood pressure, and if you look in their eyes, for example, you will see evidence of bleeding within the retina. That is a very good marker. It tells you that the number is too high for that patient. The problem we have is we have this kind of value and everyone says, oh, a blood pressure of 140 over 90 is high. Treat it, treat it, but we are all different. So that number in a 90-year-old has very different connotations to a 20-year-old and someone who's an athlete compared to someone who is elderly and very frail. You can't treat them in the same way. The benefit risk ratio of medications changes based on who that patient is.

Sarah: And Sanjay, could you explain what those different numbers are that you've mentioned? So many listeners, I assume nearly all listeners will have had their blood pressure measured at some point and will have been told, you know, there's these two different numbers. Can you explain what they mean?

Sanjay: So the two numbers that we commonly measure blood pressure with is a systolic number, a top number, and a diastolic number, which is the bottom number. The systolic pressure is the highest pressure your blood vessels are exposed to and is the pressure which happens when the heart is actually pumping blood out into the vessels. So if I had a balloon, for example, the systolic would be me blowing into the balloon. And that pressure is the systolic pressure. The diastolic pressure is if I then put my fingers at the end of that balloon. There's still a pressure, which is being exerted by the recoil of that balloon onto the thing. So if I let my hand go, the balloon flies off because of this pressure that is the diastolic pressure.

So the systolic pressure tells you about the heart rate, about how much blood is coming out of the heart, and it tells you about the capacity of the blood vessels to accommodate that pressure. The diastolic pressure is all about elastic recoil of the blood vessels, so it tells you about the health of your blood vessels. It has nothing to do with the heart, etc. The question then is, which is more important, and the systolic is more important in terms of treatment because it is the higher pressure. If your blood vessels can tolerate a pressure of 140, then we shouldn't really be too worried about a pressure of a hundred. Because it is a lower pressure and the way the pressure damages you is the higher the value, the more likely you're gonna get damaged. However, the diastolic does tell you a little bit about the health of your blood vessels. So when it comes to treating lifestyle, we'll help both. Medications tend to just lower the pressure and that is the difference. So the systolic blood pressure is more important in terms of the harm the number does to you, but both values tell you a little bit about what's going on in your body.

Sarah: And could you summarize what you think the target numbers that people should be aiming for? I know that that's a tricky question for a cardiologist.

Sanjay: I don't believe that high blood pressure or low blood pressure is a bunch of numbers. It is what that number is doing to that patient, which is very much aligned with what you guys do. Individualized medicine, high blood pressure is blood pressure that does that patient harm. It's not a number, but if a 90-year-old comes to me with a blood pressure of 150 over 90, I wouldn't automatically rush in and say, oh, hey, here, you know, you must take a tablet, etc. In fact, doing that will just raise that person's blood pressure further. So I would say, hey, look, you know, you are here, you are 90 years old. The more important thing in your case is quality of life, not I'll give you a tablet and suddenly guarantee that you'll live till 95. But this is what is happening these days because we've become so protocolized, we're so guideline-centered, we're not patient-centered anymore. In my practice, what I am interested in is taking that in the context of that patient and then working out how you bring those numbers down in as natural a way as possible. And if medications are needed, so be it, but not at the cost of that person's quality of life. That is, I think, really important.

Sarah: And you refer to those numbers as a scream for help. And people do like to put their numbers in the context of, um, you know, what the average is or when they should seek advice. So whilst I know it is very individualized, is there a number that you could give to listeners to say, look, this is what it ideally should be before you see it as a scream for help.

Sanjay: Well, if you go by the guidance 140 over 90 is sort of the kind of value. If it's sustained and it's elevated beyond that on repeated measurements, then it's probably what is considered high. Of course, different places have different criteria. So if you go to the Americans, they have low values, you know, and what is very interesting and quite absurd about the whole thing is if you have a bunch of American doctors there and you have a bunch of European doctors and you say, what is high blood pressure? The two groups give different values. The Americans will say it's 130, and the Europeans will say 140. And I say, well, okay, well why don't you just give your hypertensive patients in America one way ticket to Europe and you've cured their condition? That is ridiculous. That is how absurd the world has become. You know, this is our fixation on numbers. That is, to my mind, not the way to practice good individualized medicine. You want to see that person and you want to address them holistically rather than just targeting one set of numbers. And interestingly, those sets of numbers and those guidelines change every so often anyway.

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Sanjay: No, I'm saying the first thing is don't worry about it because worrying is only gonna increase your blood pressure. Worrying doesn't stop anyone dying or anything worrying just erodes your quality of life. So don't worry about it. I think it is important that you are empowered to understand that your blood pressure may be a manifestation of a whole host of different things and just going and getting a pill to lower it is not the answer. So I'm not saying ignore it. I'm saying it is important to take into account what that blood pressure is trying to tell you. I think it is really important for patients to educate themselves because actually we've become so protocolized, so guideline-bound that now even doctors, you know, who are doing this have only been taught well, the blood pressure is this value. You've just gotta hit it with tablets. Hard, hard, hard. And so I'm very much for patients understanding that it is nuanced. I am very much for patients saying, okay, my blood pressure is high. How is it measured? Is it just a one-off? Is it a crude measurement? Is it sustained? Has it been done in a better way?

Has it been measured? Because blood pressure, you know, when you go to your doctor's office and have your blood pressure checked, that's a very artificial environment. The heart rate's gonna be up, you're gonna be stressed, etc. If on the basis of that you are told that you have this diagnosis that you have to then carry around as a label for the rest of your life? Well, I think I have an issue with that. I think what we need is patients to realize that that's a very crude reading. You want a better way before you are labeled with something like that to measure it. And then I think you have to have a detailed evaluation of whether that number is actually harming you. And if you have all that information, then you are in a better position to make lifestyle choices and even start treatment and then have your measurements repeated in the same way. Not, oh, I had a very sophisticated 24 hour blood pressure monitor first, and then I went to my doctor and he did a hand reading and he says, it's not coming down. Well, you have to compare apples with apples. So I think that we should never ignore something. I think worrying about it doesn't sort the problem out, but I do think that we are in an era, especially with the internet, where patients are keen for more information and they're keen to feel more empowered about taking charge of these things.

Sarah: This is a really important point we see in our own research, and this is in a research setting, which is slightly similar to the doctor setting, that there's a huge change upon repeat visits in blood pressure readings. So when they first come to us to get their blood pressure done, compared to the second time, there's quite a significantly higher blood pressure reading the first time versus second time. I know at the doctor's surgery, it's called white coat hypertension. And that's why I think what you've just said now is really important, that you don't just take a one off reading, that you do repeat readings.

Jonathan: And why is that?

Sanjay: Because if I do my blood pressure now whilst facing all your complex questions, it's gonna be higher than when I go home.

Jonathan: Because you are anxious. Your heart rate is higher

Sanjay: Yeah, absolutely. So for me to be labeled with a condition that is gonna afflict the rest of my life, and it is not just about having a label, it'll affect my insurance, it'll affect everything. And it'll cause my blood pressure to go up as well, to be told now I have a medical condition which is associated with a very high risk of heart attacks and strokes. So I think it's very important that we are more responsible and we do the harder thing, which is a more detailed evaluation of the patient rather than this standard, oh, let's just do a blood pressure now with automated machines as well. So there's a lot of scope there, and I think that one would say that almost a quarter of people who are told who have high blood pressure probably don't have sustained hypertension, and they end up carrying this label, taking medications, suffering the indignity of side effects, etc. So much more detailed readings are important.

Another point to mention is that I think when we talk about blood pressure, the question is how do we know blood pressure is a bad thing? Okay, well we know because someone has done some research and said, okay, high blood pressure is associated with bad things, but you've got a variable that is constantly moving. So how did those people do that research? Because we are following on from that research, and so most people do a much more sophisticated reading of the blood pressure, these sustained readings, etc. Whereas what that is now degraded into is these, oh, come to clinic two or three times in a month, and if your blood pressure's high, we'll just put you on some tablets.

Sarah: Yeah, and I think the really good news is blood pressure monitors are very cheap. They're very easy to access. Most people can just get them from, you know, shops that are nearby. They're about 40 pounds in the uk, similar dollars in the us and these are ones that are typically accredited with hypertension societies. So it is something you can measure at home, and then you can do these repeat measures and also at different times in the day.

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Jonathan: Before we move on, can you clarify what would happen if my blood pressure is high and I don't do anything to treat that.

Sanjay: If it is high and your blood pressure is damaging you, then that damage will accrue over the number of years and will then translate into signs of visible damage. So those include dysfunction of the brain, so things like dementia, strokes, heart attacks. Because the heart is a muscle and has to push against a higher blood pressure all the time, the heart becomes more and more muscular, and after eventually it becomes so muscular that it outstrips its own blood supply and can then lead to heart failure. And also where our tiniest blood vessels are in our eyes and our kidneys. The eyes can get damaged and the kidneys can get damaged, and high blood pressure can lead to progressive renal failure as well. So eventually, because the blood vessels supply all the organs, blood pressure will have an impact, an adverse impact on virtually all our organs. But the most notable ones are the brain, the heart, the kidneys, and the eyes.

Jonathan: Listening to that, firstly, it's pretty serious if you do nothing about it is my takeaway.

Sanjay: Absolutely. Absolutely.

Jonathan: But the second thing I'm really surprised by is I had no idea I had anything to do with my brain or dementia. I always think about blood pressure as something to do with my heart and heart attacks. Have we always known this? And this is just like poor pr?

Sanjay: No, I think the problem is that you can only measure that which you can see. Dementia is something you don't actually see until it becomes very advanced. So again, empowering people to realize that these are not processes that don't do anything to you, and then one day something bad happens is perhaps a very simplistic view. There's stuff going on in your body. And that damage is happening, happening, happening, and then it starts showing up 10, 15, 20 years later.

Jonathan: So I could have high blood pressure and it could be causing this like very small damage into my brain, for example, over as long as 20 years before anyone sees the results of dementia.

Sanjay: Yeah, absolutely. I'm very convinced that that happens.

Jonathan: Just to come back to the numbers for a minute. Because I think you both really emphasized the fact that one single measurement in the doctor's lab is the worst possible way to tell whether or not I have high blood pressure. But let's say I've done this over an extended period of time, it's a measurement that you would believe was quite accurate. What would be a number that would make me feel good? That it's sort of low enough. And how many of us today in the Western world are sort of higher than that range.

Sanjay: So one would argue that certainly in the UK, one in four people have hypertension.

Jonathan: One in four.

Sanjay: Oh yeah. Globally it's about 30%.

Jonathan: Wow.

Sanjay: They have hypertension, meaning their numbers are higher than what the guidelines recommend in terms of numbers, I think also it's important to understand that your number may be within normal range, but may still be high for you and may still be harming you, and therefore that is why it's so useful to look for evidence of harm because you understand that person. If we are just going on the superficial side and saying, oh, what number will keep me happy? I'd say if it's below 140 over 90, then that's what the guidelines say is acceptable. Right. We are in the business of treating populations, and when you're trying to treat populations, resources tend to be a little bit more limited. You want to do the easiest thing, et cetera, et cetera, and that's why things are happening. But I think there is a better way of doing it. So if I have a patient, I would say, well, look first, let me work out what your number is. Let's work with one number, not it's 120 of 80 now, it was 130 of 80 10 minutes ago. Yesterday was 125. What is your number? Let's get one number, then let's see whether that number is high for you. And I would do that by looking at the back of their eyes, making sure there's no bleeding. I'd look at their heart, is the heart more muscular than normal? That tells me about that person. And then I would say, okay, we have evidence that your number is a little bit where people would say it's high and there's some evidence of damage, so that makes it more urgent. We do something about it. And that should always be with education. Lifestyle management. Potentially medications. And then I would then bring them back and I would say, let's look at all those things again. Let's repeat the blood pressure and see if your numbers come down. Let's see if your body mass index is a bit better. Let's see if you're eating better. Let's see what these medications are doing. Are they actually destroying your quality of life or are they suiting you? And how effective are those interventions by repeating that 24 hour blood pressure monitor. And that is like the way I think it should be done. For patients.

Sarah: And Sanjay, there'll be lots of people that won't have the privilege to come and see a cardiologist like yourself. And I know that hypertension is often called the silent killer. Are there any symptoms that people at home could look out for themselves?

Sanjay: Yeah, I think, I mean, certainly things like fatigue, headaches, breathlessness, when you are exercising because your heart has to work against a higher pressure will.

Jonathan: Everyone who has high blood pressure has symptoms and therefore know that something's going wrong.

Sanjay: No, not at all. Only a minority of people who have elevated blood pressure actually develop symptoms to the extent that they know something is wrong.

Jonathan: That does not sound good. I think I now understand anything that's called the silent killer is something that clearly I don't want to have. I think we understand now that this can be really serious condition. That also that there's, there's nuance beyond just like one single number and that it's really common. I'd love to understand what causes the high blood pressure, because I assume that, you know, my 6-year-old daughter probably does not have high blood pressure and that most of the people who could come to see you also when they were six years old did not. So this is something that develops over time. The only thing I know about it, somehow eating lots of salt is supposed to be bad. I think that's what I grew up being told and being very stressed. Is that the answer?

Sanjay: No, I think there's a lot more to it than that, and we're beginning to realize it, and I think that our nutrition plays a huge role. My belief is that the food industry is bothered about our taste, not about our health. And so a lot of compromises are made and we're consuming all sorts of things that we have no idea of because they're packaged in a way which is sold to us as healthy. I think alcohol plays a role. I think lack of sleep I think is huge. There are certain supplements which have been eroded in our diet, magnesium, for example. Due to modern farming methods and processing and all those things probably also have an impact on blood pressure. So I think there are a ton of things in our environment, in our lifestyle which contribute to essentially premature aging of our blood vessels, which then becomes stiffer and the blood pressure keeps going up. Obesity being a big thing, lack of exercise being a big thing.

Sarah: Something that I'm really interested in is the variability in response to salt. Now, I know at a population level, if you reduce your salt intake, about 75% of people will get some sort of reduction in blood pressure. What we see is about 25% of them actually get a really big reduction. So really big benefit. They're salt sensitive, and yet we see that there are a proportion of people actually have no benefit from reducing their salt intake. So as a kind of public health policy, many countries are focused on salt as a target, which is great because yes, at a population level it's important, but I think we should be thinking about it a little bit differently. And I'd love to hear your view on potassium and how important that is because I think we need to change the narrative a little bit around this.

Sanjay: Absolutely. I completely get that. With regards to your question about potassium, absolutely. There are data to show that actually a higher potassium increases salt excretion. It's better for endothelial function. It's a vasodilator, it suppresses the hormonal mechanisms in the body, which regulate pressure. So potassium supplementation will also do these things. And those are all things, and I don't think it's necessarily also going to be for everyone, just like salt. Maybe these are things that we need to understand that patient and we need to see whether that works for that patient. And then we need to have ways by which we measure that pressure again, to get an accurate representation of what it's doing. You know? So they have to be proper clinical studies and they have to go on for a long period of time, and ideally they need to be measuring hard outcomes.

Sanjay: Certainly age contributes and you can't do much about that. But I think all those things that come along with a Western lifestyle. Putting on weight, more stress, a reliance on fast foods, reliance on processed foods, all those things that are designed to make our lives easier in some ways, probably have an impact on all that and may contribute to our pressures going up. If you look at the data, the prevalence of hypertension under the age of 40 is 10%. It goes up, you know, 40 to 60, it becomes almost 30 40%, and then above 60 it's over 60%. So more than one in two people have high blood pressure. Once you get to 60. This is with all the research, with all the tools that we have at our disposal. Clearly it isn't working. Why is this happening? And therefore we have to have the courage to start thinking differently. And I think this is where holistic, individualized healthcare comes in, where we should be integrating and we should be collaborating with nutritionists and all these people, you know. For that person.

Sarah: And Sanjay, I've seen estimates that about 70% of the variability in blood pressure IE, the chance of you developing high blood pressure is due to modifiable factors, so factors that are within our control. You've listed a few of these, age obviously isn't one of them, but you've listed diet, stress and body weight. Are there any other factors that are also within our control that we can do something about to prevent this rise in blood pressure?

Sanjay: I think sleep is really important. Exercise is important. Diet, what you're putting in your body, things like smoking, alcohol, excess, and stress.

Sarah: And why is it that stress impacts our blood pressure?

Sanjay: Because stress is in so many ways associated with all those kind of hormones that are produced, which actually constrict our blood vessels. So if you're in a state of chronic stress, our blood vessels are gonna be much tighter in general. And that will then contribute to the blood pressure going up. And of course, stress will affect your sleep.

Sarah: Yeah.

Sanjay: When you don't sleep, you develop a predilection for sweet foods. When you develop a predilection for sweet foods, you get these huge surges in insulin, so it's all interlinked, and it's also very important. I think, that people become a lot more aware of the food industry and what the food industry is all about and what kind of compromises are made with your food before it ends up on your table. It's important to understand that sometimes your blood pressure is a manifestation, an outwardly manifestation of the compromises you're placing on your body, and therefore, it shouldn't be looked upon as, oh, blood pressure is the worst thing in the world. It should be what you're doing to your body. That western lifestyle is probably more harmful. Stress is probably more harmful if you're smoking a hundred cigarettes a day. That's more harmful than trying to control the blood pressure that has risen as a consequence of that.

Sarah: Yeah, I think it's a great way of looking at it. It's a symptom of our lifestyle. It's a symptom of what's in our supermarket and our grocery stores.

Sanjay: A hundred percent. And if you look at diabetes, type one diabetes is a condition, but type two diabetes for most people is a symptom that I think is really important.

Jonathan: What about our gut microbiome? Sarah, I know you've done some research on this. What have you found?

Sarah: Yeah, so we've done quite a lot of work at ZOE and at Kings College London, looking at microbiome and links with blood pressure. So firstly, we've run a study in the twins department, which Tim Spector, that one of the co-founders at ZOE, oversees. What we found was that there's a different microbiome composition between those people who have hypertension, so have high blood pressure versus those that have normal blood pressure. We also see a different in the diversity, so how diverse that microbiome is, which we know is quite important in terms of health. We've also looked at this in our own ZOE studies, so in up to 35,000 people now we've looked at this. Um, what we see is that there's actually a microbial signature, so there's this signature of specific species, so specific bugs in our gut that are linked with a high blood pressure. And conversely, a signature that's linked with low blood pressure. And we've actually replicated this and recently published it a couple of weeks ago in nature. Um, we've looked at this in lots and lots of different cohorts, and consistently we see it's these same bugs associated with a higher blood pressure, same bugs associated with low blood pressure. We don't fully understand why we think one of the reasons. Going back to low grade inflammation. We know that these species release different chemicals like short-chain fatty acids. Um, they're involved in how they process other food debris that's reaching our gut. That may also impact how the lining of our blood vessels, interact, how constrictive they are and so forth. So the mechanistic stuff is, I think, where it gets interesting, where we need to learn a bit more. But I think the results that we've seen are really exciting and could be a potential target for the future as well, because instead of just treating the symptom, we'll be treating one of the underlying causes. And this is why diet's so important. We know diet impacts those microbes.

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Sanjay: And I think this is exactly where we need to be heading. And it would be really interesting to see whether what your findings not only benefit people with high blood pressure, but also with type two diabetes. Also with obesity also, because I think they're all different screams from an unhappy body, and I see this all the time. I see this, so I will go up to my coronary care unit and I'll have a patient there who's had a heart attack, so let's say a 60-year-old man heart attack. And I'd say, well, what are his risk factors? And the doctor who's presenting the patient will say, oh, he's had diabetes and high blood pressure. And I said, how long has he had diabetes and high blood pressure? Oh, well, he's had diabetes and high blood pressure for 20 years. And I say, okay, and has he been treated for those? And they say, yeah, he's been on tablets.

And I say, so why has he had a heart attack? Because he has diabetes and high blood pressure, so what were we treating him for? But no one looks at it like that. No one says, okay, perhaps that is a failure in the treatment that we've been giving that patient that he has still ended up having the outcome. You know, we have to be a little bit more reflective. We can't just say, oh, he's been on treatment. But heigh-ho. People on treatment still have heart attacks.

Jonathan: And Sanjay, is that why you were saying things aren't working in terms of treating high blood pressure? Is this what you're saying?

Sanjay: Absolutely. I think more people are having heart attacks. I think younger people are having heart attacks. I think places like America where they have stricter guidelines still have more heart attacks than other places.

Jonathan: So the current treatment for blood pressure isn't actually reducing the heart attacks and the dementia and these other sorts of things you've been talking about.

Sanjay: Yeah, and if you look at the data, the number needed to treat is the number needed to treat being an idea as to how many people you have to treat to achieve benefit in one person, be that some kind of reduction in a heart endpoint death, or a heart attack or something like that. And the number needed to treat is big. You may have to treat between 30 and 60 people for several years to achieve benefit in one person. So the question then is we have to look at that and say, is that good enough? If those were the returns in a bank, I wouldn't be putting my money in that bank.

Jonathan: So I would love to switch here actually into therefore what people can do, because I think lots of listeners like me are probably coming away saying, well, this high blood pressure thing sounds quite serious. I'd like to know what I can do to not just lower my number, it sounds like, of blood pressure, but actually lower my risk of having these heart attacks and strokes and, and so on. How would you advise me to get that sort of one good reading to see whether or not I should be worried about this?

Sanjay: I don't think it'll be a case of one reading, because I think the first reading tends to be a little bit higher and then the second readings are a little bit lower and the third reading's even better. But whatever you do, you are looking for changes. You want to do the same thing every time so that you're comparing apples with apples. So I would say perhaps, you know, you measure your blood pressure twice a day, do three recordings, record the third one on each occasion, and do that for a few days, and you calculate a general average from that and if that's okay, and you are doing the best you can in terms of your lifestyle. That's okay.

Jonathan: What's the number that you would say it's worth going and having a conversation with your physician?

Sanjay: Well, I certainly think if it's like 160, you know, some people would say even over 140 persistently, then it's a good idea to go and see your physician. And you take those readings with you and show them to them because at the end of the day when the physician measures, it's just gonna be higher. So I don't understand why one would put more credence in that. And I think it's always really, really important that the minute you start thinking about your blood pressure, you must think of your lifestyle. That is the thing that I think a poor lifestyle probably kills more people than anything else.

Sarah: We know that diet and lifestyle plays a huge role in this. I'd love to hear from you in order of what you think is the most important, the diet and lifestyle factors that people can think about changing.

Sanjay: Certainly there's a lot of reliance on kind of fast foods, you know, unhealthy foods, some of which we know are unhealthy, but we still do it because it makes our lives easier. And some which we don't even know are unhealthy, and I think that would have an impact on everything else as well.

Sarah: Yeah.

Sanjay: Sleep, stress, weight gain, I think it'll have an impact on all that. So nutrition I think is perhaps the most important thing of all, because stress is huge, but it's very difficult to quantify stress. Food is something that people can make a change to. I think exercise, cardiovascular exercise is important, but people are becoming more conscious of exercise, and they are doing more. But all those things you cannot do lots of exercise and then be really proud that you can get away with four hours of sleep every night. You have to do it all.

Sarah: Now I think the four pillars of health that you are talking about, sleep, stress, activity, and diet. Yeah. Are not just gonna help blood pressure. They help every single disease, but they help how you feel in the here and now. Absolutely. And I think that's really important from a motivational point of view. From a dietary perspective, what are the kind of recommendations that you would make to someone coming to your clinic who has high blood pressure?

Sanjay: I personally think sugar is the enemy. Because sugar causes a bunch of insulin spikes, whereas a lot of blood pressure is about cut down salt. Yeah, cut down salt. I think sugar is the more important thing, and I think that processed foods, refined oils, all those kind of things, additives,

Jonathan: And Sarah, what's your experience in terms of thinking about blood pressure specifically and what dietary changes you might suggest to someone based upon, you know, your research and others?

Sarah: So I think that what constitutes a general healthy dietary pattern for everyone will also help with blood pressure. So that's a diet high in unprocessed foods, a diet high in whole fruits, vegetables, beans, whole grains. A diet low in processed red meat, low in sugar sweetened beverages. A diet low in refined carbohydrates that causes these big peaks and dips that can lead to inflammation. There are a few additional recommendations. So one, is to increase your potassium intake, but to increase your potassium intake actually through diet constitutes a healthy diet. It's mainly achieved through increasing your intake of fruits, vegetables, pulses, you know, beans for example. They're really high in potassium. So plant foods are very high in potassium. Some are higher than others. So if we think about fruits for example, um, typically. Bananas, figs, apricots, they're very high in potassium. If we're thinking about vegetables, lots of green leafy vegetables like spinach are high in potassium. Interestingly, in the UK most of our potassium actually comes from potatoes because we're a nation of potato lovers. Um, and crisps, they are quite high in potassium. Obviously, be careful how you are having your potatoes to contribute towards your potassium. Because they don't have much else unless you're keeping all their skin on for the fiber. They don't have much else that's necessarily improving your diet.

Jonathan: I love it's the first time you've ever managed to find an excuse for why we should be eating potatoes here. Gone.

Sarah: Jonathan doesn't like potatoes, by the way. And so potassium is one single nutrient that yes, we know from clinical trials that use potassium supplementation as well as supplementing through the diet can reduce blood pressure. I did a randomized control trial on this many years ago. We also know salt is important. But the real important point to make here is that reducing your salt intake isn't gonna benefit everyone. That you will have some people who are salt sensitive, who will have a really large benefit from reducing their salt, um, in order to reduce their blood pressure. Some people have no benefit generally at population level. If we reduce our salt, yes, we benefit.

Jonathan: And where is most salt in our diet today?

Sarah: So most salt in our diet is in food that's pre-prepared. That's prepackaged. Only about 20% of salt comes from food that we make or that we add at the table. And so we call this discretionary salt, that there's actually very little salt now added at the table. About 70 to 80% of the salt that we consume in the UK, in the US and many countries come from heavily processed foods, prepackaged foods, pre-made meals, and so. Really, if you're just following a basic healthy diet, cutting out all of these heavily processed, prepackaged foods, if you're switching to a more whole food plant-based diet, you are naturally going to increase your potassium or naturally going to reduce your salt. You are adding in fiber. Which we also know can reduce our blood pressure through various mechanisms, one of which is through improving the composition of the gut microbiome. And you are also adding in by going to a very whole plant-based diet, you are also adding in lots of other nutrients that we know are important. And Sanjay mentioned earlier about magnesium. It might only play a small role, but again, you know, cumulatively you are adding in lots of components to the diet that are going to help your blood pressure improve your microbiome, reduce inflammation and so forth.

Jonathan: And you talked earlier about this new study showing like these particular microbes linked to, you know, high blood pressure or not. Is it possible to get more of the good ones and fewer of the bad ones? Through my diet.

Sarah: So we've recently published research from our ZOE Studies where we've seen that by changing your diet, you can change these specific microbes that you can change the microbiome signature that you have, and so you can increase the microbes that are associated with lower blood pressure and you can reduce the microbes that are associated with higher blood pressure from switching from a typical kind of UK diet to the kind of diet that we promote at ZOE. Going back to the microbiome as well. I think we are starting to see studies emerging where people are giving probiotic supplements, and these are often single strains, or they might have multiple different strains in them and they see reductions in blood pressure specifically through adding in particular species. And so this is where I think, again, it's getting really interesting that you'll see an even greater effect by changing your microbiome through the diet to reduce your blood pressure.

Jonathan: We've covered a lot of the different things you could do. I'd just like to talk about exercise. A little bit more. Is there evidence that doing more exercise can reduce my blood pressure?

Sanjay: Absolutely. So, some data indicate that if you do cardiovascular exercise, your blood pressure can come down by an average of six millimeters of mercury.

Jonathan: Sanjay, is that good?

Sanjay: It's comparable to some medications that we get.

Jonathan: Okay, so that's a lot.

Sanjay: It's good. Yeah. And then there is additional benefit because with the weight loss, for every kilo you lose, your blood pressure comes down by one to two millimeters of mercury, your systolic blood pressure. So not only is the weight loss helpful, but weight loss plus exercise, there is data to suggest that they benefit.

Jonathan: So it's interesting what you just said. So you're saying in all of these things, if, if they also help you to reduce your weight, then you are going to reduce your blood pressure. Because this extra weight is pushing up your blood pressure.

Sanjay: Yeah. And you're going to reduce your blood pressure and you're going to reduce your reliance on medications, some of which also increase your blood pressure. What we are not doing is we're not making a healthier population at this point in time. We are making it a medicated population, and I think we have to start going back and focusing on the things that we can do to make our population healthier, slimmer, more mobile, less stressed, less medicated, and that is the way we will achieve something different to what we are at this point in time.

Jonathan: If our listeners started making, you know, these sorts of changes that you're talking about, how fast could they expect to see it have an impact on their blood pressure and how big an impact, you know, can that be versus, you know, taking the pill that otherwise you are offering to them.

Sanjay: The first thing is they'll feel better, and that feeling better will become noticeable after only a few weeks. I suspect it's very dramatic and if for no other reason, rather than just saying, oh, I'll do these things because my number will come down, you should do it because you will feel better. You will have a better quality of life. If you feel more rested, you're happier, you eat putting good stuff in your body, you're feeling more confident, you go to the doctor, the blood pressure will be lower.

Sarah: And I think this is really motivational because we know from our own research, people changing their diet, changing their lifestyle. You start to feel better within days. And we know from published research on dietary studies, looking at dietary modifications to improve blood pressure, you can see improvements in blood pressure in as little as two weeks. So it's not something that's gonna take months and months. Make that change now. Start with small changes. Build them up and you will feel better, but you will see a difference in your numbers as well quite quickly.

Jonathan: Amazing. Thank you so much. This was definitely, it was a new topic for me, quite complicated to understand. I'm gonna try and summarize it and please correct me if I've got anything wrong. Both of you. I feel like I'm about to do an exam. So the thing that I'm actually most amazed by is this new discovery that there are specific bugs in our gut linked to high blood pressure and low blood pressure, which is extraordinary. We don't fully understand why, but we think it might be linked to this long-term inflammation. About a quarter of people are told by their doctor they have high blood pressure, but they don't because when you go in and see your doctor, you're really anxious and your heart rate goes up. And so you have this measurement that is higher than your average would be. And I think you said about 30% of people globally have high blood pressure. That short-term high blood pressure is fine. Like I run for the bus, it's nothing to worry about. This, like long-term high blood pressure over years and decades can be really harmful. And that affects things like my brain. So dementia could be starting 15 or 20 years earlier with these, like tiny damage to blood vessels from the high blood pressure, strokes, heart attack, heart failure, but also, you know, your eyes could get damaged, your kidneys. So this is really important. The numbers that we use to measure it, they have these two numbers, and the first one is the one that you're saying I should really worry about the big number, the systolic number, because that's what happens when my heart is pressing really high. But interestingly, doctors do not agree around the world even about what that number is that you should worry about.

Jonathan: So in America, it's 130. In Europe, doctors are more relaxed and you can get up to 140. It is good to measure your own, blood pressure, but not to obsess about it and you know, if you're gonna measure it at home. Then you said multiple times in the day that each time you do sort of three recordings, sort of write down the last one, do it for a couple of days. That gives you sort of average, which is gonna be much more accurate than the sort of one single measurement. And I think you said, well, you know, if that is above the guidelines in your country, then it's worth going and talking to your physician and share this data. But for the reasons we talked about, it needs to then be looked at in the context of your overall health. And then we talk about what could you actually do? And I think interesting, there was this really big alignment, Sanjay, between you and Sarah. And of course Sarah's gonna focus on nutrition as a nutrition scientist. But actually you said like diet is the number one thing that you think is affecting high blood pressure, which is extraordinary that the overall healthy diet for blood pressure is the same as the overall diet for everything else, but there are some interesting specific things there. And what I caught was particularly increasing your potassium intake, and that means more fruits and vegetables. And you had some particular examples. I think I got bananas, figs, apricots, right? Green leafy vegetables like spinach. These are particularly high in potassium. Reducing salt is good, but actually the salt isn't where I guess I would think it is, which is adding lots of salt at the table. This is mainly in heavily processed food, so it's sort of hiding in a lot of these meals and sort of ready meals and things like that. So actually, if you can cut back on that, I can still add, you know, salt to the eggs that I make at home without feeling so bad.

Sarah: Absolutely. And I think what's really interesting is that your taste buds change very quickly. We become so used to that salty taste. So actually, if you can cut down your salt intake from these heavily processed foods, quite quickly, you'll realize you don't need to be adding much salt at the table because you become more sensitive to it.

Jonathan: And finally, more fiber. Supports the microbiome, hopefully helps to give you those good bugs that you want to have fighting the blood pressure. But then it's not only about diet, we talked about stress a lot, but also that it's hard to adjust for. So these other things like sleep and exercise that we know are so important for many other aspects of our health, like very strong data to support the fact that it can reduce our blood pressure. And not only will we reduce our blood pressure at the end of this Sanjay, but we're all gonna feel better, which sounds a great way to, to wrap up.