Leah:
Hello and welcome to The Ideal Nutrition Podcast. I am Leah Higl and I’m here with my co-host Aidan Muir. And today’s topic is nutrition for reducing blood pressure. So probably not going to be applicable to everyone, but for those who it is applicable to, probably going to be super helpful. So the main reason we want to talk about this or the main reason it’s important is because high blood pressure can contribute to the risk of cardiovascular disease or heart disease or complications with that, as well as kidney conditions too. So it’s obviously something that is going to be very detrimental to your health if you let it linger on. So we’re going to go through different nutrition strategies you may be able to do in your day-to-day life to have that come down.
Aidan:
Starting with the obvious one, the most common recommendation is to reduce sodium intake if it is high. And that’s not a controversial opinion, I don’t think, but we’ll talk about that. There is a lot of people who will argue the other side of things, so we will go through that. But yeah, reduce sodium intake if it’s high, or salt intake, but you also probably want to avoid going excessively low. Pretty prudent advice. Looking at it from the perspective of being like why is this common advice and why should it not necessarily be controversial at a population level? There was a 2019 systematic review that covered pretty much all the research on this topic that clearly concluded that reducing sodium intake decrease blood pressure on average and reduce morbidity and mortality from cardiovascular diseases.
So not only is it reducing blood pressure, it’s also carrying over to the outcomes that we actually care about, which I think is important too because in other areas of research sometimes we don’t see that. For example, the Mediterranean diet does not appear to reduce LDL cholesterol, but it reduces the risk of these issues arising from cardiovascular disease, and it’s like sometimes these metrics do not always perfectly line up. In this case we do see it line up. The mechanism involves a few things. The first one is that sodium increases water retention and that is in the blood as well and that can cause this kind of expansion and increase in blood pressure and it can also be an increase in arterial stiffness as well. In terms of how much this matters, because I think it’s important to add context around this, a randomized control trial identified at dropping from 3,700 milligrams per day down to 2000 milligrams per day, reduced systolic blood pressure by about 7.1 units on average.
So if we’re looking at good blood pressure being below 120 over 80, that kind of adds a bit of context being like this reduces about 7.1. And for context, so that was like 3,700 down to 2000, the average person consumes 3,500 to 5,500 milligrams per day. I think that number is pretty important to put into the context of whether there’s any controversy over this kind of simple recommendation being like the average person already has quite a high sodium intake. So there is more nuance to it, obviously, some people have low sodium intake and everything like that, some people have higher needs, but on average the average person consumes a relatively high intake.
Leah:
Yeah, and going back to controversy around sodium intake, there are definitely criticisms of reducing sodium intake and that advice around it. So the three main ones are, so one, sodium sensitivity doesn’t affect everyone. So some people are just not sensitive to this high sodium intake and they’re going to just excrete most of it anyway as needed. Second is there is a J-shaped curve of sodium and cardiovascular disease outcomes, and I will touch on that a bit more in terms of what that actually means. But the third is athletes having higher needs. So that is a common criticism in that athletes probably sweat more and excrete more sodium, so their requirements are usually going to be higher. So individually going through those. So number one, sodium mediated hypertension is a thing. So statistically a large percentage of people who have hypertension are also sensitive to sodium, meaning that if you are hypertensive, if you have high blood pressure, it’s still probably good advice to have a moderated or lower sodium intake than what would be kind of the general usual intake for the general person.
The J-shaped curve thing. So that sounds complex but basically what that means is that you can basically go too low with your sodium intake. So having this, I guess, a general rule of like, oh, just reduce your sodium intake, sometimes garners criticism because you can take it too far to the extreme, take it too low where it’s still going to increase potential risk of CVD or cardiovascular disease outcomes by going too low. And that’s pretty easy to overcome in that just don’t go excessively low and it’s going to be quite difficult for you to go excessively low. You’d really have to try, especially with people’s kind of usual intake being above the RDI usually anyway.
Aidan:
Yeah, so far. I think the only way it happens is people who try to eat super clean in that they never eat anything from a package and they never add salt to anything ever. That’s the only case to truly happen.
Leah:
You’d really have to try. So even though it’s a criticism, it’s not one that I would spend too long thinking about. And yeah, I kind of went a little bit into the athlete stuff, but athletes generally not the most prone to being hypertensive. They’re usually fit people who are a healthy weight and they have higher needs from more sodium excretion through sweat and urine and stuff anyway, so probably don’t need to really discuss that too much here. Overall a safe guide is to aim for over a 1000 milligrams of sodium per day, but probably less than 2000 milligrams per day if you are hypertensive. Obviously, it needs to be individualized, all these things need to be taken into consideration, but that’s kind of a general ballpark figure. It’s also not something that I would go out of your way to count milligram by milligram each day. I’d rather take a more food approach in terms of maybe you just limit your packaged food, so you try not to add too much salt to food, those kinds of more generalized recommendations rather than trying to count your sodium intake, which would be incredibly difficult.
Aidan:
Yeah. With the sodium mediated hypertension thing, I looked into that a lot in preparation for this podcast because I’m like that is an interesting thing and that was how we came to the conclusion that it’s like a lot of people with hypertension also have sodium mediated hypertension, but I was like how do you know if you do or don’t have that, right? And right now there is no validated test to know that, which also kind of doubles down why it’s pretty prudent advice to reduce sodium intake if you do have hypertension.
But the most proposed way of testing this is literally just to test it and have a blood pressure monitor and go have a couple of days low sodium intake, have a couple days higher sodium intake. If there’s no difference, you likely don’t have it. If there is a difference, you likely do have it. But as we know there’s other things that factor into this and it’s not that nice neat test that works perfectly, there can be other explanations for high blood pressure or lower blood pressure, but the best way we’ve got of testing that is quite literally just to try and test it yourself, basically.
Leah:
Yeah, totally.
Aidan:
So the next one we’ll talk about is an overall strategy for reducing blood pressure called the DASH diet, which literally stands for dietary approaches to stopping hypertension. And it’s not an approach I actually ever use with clients, but it’s something that I think we can learn a lot from. It was obviously a diet that was just designed for hypertension. It contains a lot of foods that are particularly high in magnesium, potassium, and calcium, so these electrolytes. It has a lot of fruits, vegetables, nuts, seeds, whole grains, and dairy. So depending on your view on whole grains and dairy, you could classify this as high in certain healthy foods. And it also has a moderate intake of healthy fats and some lean meats as well, and a bit of fish too. In terms of outcomes, it has been shown to reduce blood pressure significantly, even without any changes in body weight and without any changes in sodium, which is pretty impressive as well considering what we just talked about.
And that’s obviously another clear-cut sign that sodium’s not the only thing that matters, it’s just one of these factors. One study, under those conditions where it didn’t affect sodium or body weight, found a reduction of 11.4 units in systolic blood pressure and then 5.5 in diastolic blood pressure, which is pretty impressive. It’s rare for many studies to have that large of an impact on blood pressure without medication or anything like that, particularly in kind of outpatient settings. And even though it’s effective without reducing sodium, the researchers found that it’s even more effective when sodium is reduced too. I don’t know about you, but I remember when I go onto bodybuilding.com and everyone was like, sodium doesn’t matter, it’s just about being lean and everything like that. One of the first things I did to kind of fact check that for myself was just, firstly, look at the research but then I remember looking at the DASH diet and seeing that when they reduced sodium it was even more effective.
Little stuff like that is like, okay, it’s very dismissive to say sodium doesn’t matter at all. It’s not the only factor that matters but it still matters.
Yeah, exactly. And some people will question certain aspects of the diet such as the whole grain and the dairy aspect and the amounts that they use. Personally, that’s actually one factor as to why I don’t use it with many of my clients in terms of it’s a lot of whole grain serves. From memory, like the Australian diet healthy eating is already high in whole grain serves. It’s higher than that, it’s significantly higher than that as well. And it’s lower protein than the typical diet that I would give to a lot of my clients, which is why I’m saying I don’t necessarily use this but I can learn from it. But there was a systematic review of 28 studies on this topic, finding that whole grain and dairy both significantly reduced risk of hypertension and there’s a bunch of reasons for that. Even dairy itself is really high in potassium and it’s really high in calcium as well. There’s a bunch of these things that go into it.
Leah:
Next thing we’re going to touch on is potassium. So one thing you might be able to do in terms of reducing your blood pressure would be to increase your potassium intake. So arguably this is just as important as a reduction in sodium intake and it can be quite effective. So high potassium intake is also potentially a large factor in why the DASH diet is so effective in managing hypertension because you are increasing these foods that are potassium-rich. Theoretically this is because potassium increases sodium excretion and relaxes the walls of the blood vessels. Research on urinary excretion rates does indicate that those with the highest sodium intake and lowest potassium intake typically have the highest blood pressure in the research. So for context, the RDI for potassium is 3,800 milligrams for men and 2,800 milligrams for women. But approaches like the DASH diet are almost 5,000 milligrams, so 4,800 milligrams. So even more than the recommended daily intake that is set.
The average person generally consumes far less than what’s recommended by the DASH diet and even far less than what is recommended in terms of the recommended daily intake. And that’s probably because generally we do not consume enough fruits, veg, whole grains, nuts, seeds, legumes, all these things that are going to be really good in a high in potassium. Something as a little caveat to this is if you have kidney conditions, it’s definitely worth checking with your healthcare team, with your doctor, before you go ahead and increase your potassium. In terms of supplementing potassium individually, so not using a food first approach and supplementing instead, there’s really not a lot of evidence or support for that in regards to reducing high blood pressure. Instead, my approach with clients is definitely to go for those foods first. So leafy greens, beans, nuts, dairy foods, starchy veg, they all tend to be the highest in potassium, but generally a lot of those plant-based foods you can’t go wrong with.
Aidan:
Yeah, adding a bit more on the potassium. The supplementation one has been interesting to me because I can’t see any reason why not to supplement. I haven’t seen many people talk about why it would be detrimental, but I also haven’t seen anybody recommending it. Which is it’s enough for me to be like, I don’t know, we can get this through food, we should get this through food. If we look at supplementing potassium, we could then look at supplementing everything.
I don’t just have a, it is a complex thing, but I view it just being like, let’s just try to get it through food because I can’t see any reason not to. One of the complex things with potassium is it is in a lot of stuff, but there’s nothing that has a really high amount individually. Adding context to that, everybody talks about how bananas are high in potassium, one banana is about 400 milligrams of potassium. We’re looking at, using the DASH diet as an example, 4,800. That’s not even 10%. Whereas if we’re looking at Vitamin C, an orange is more than a 100% of the recommended daily intake of Vitamin C. You need a lot of high potassium foods to reach these numbers. Another way I look at is, firstly, increasing fruit and vegetable intake amongst other stuff, but it’s almost like if you spend a lot of your calorie budget on low potassium foods, like a lot of added sugar, a lot of added fat and a bunch of other stuff as well, more so like junk food or whatever, you’re taking away from your opportunity to get more potassium in.
Leah:
Yeah, I think that’s a better way to look at it, for sure. And I think just taking that multi-pronged approach, usually you’re not just going to, if you are hypertensive, you’re probably not just going to be thinking about potassium alone. Maybe if you’re carry, we’ll talk about this, but carrying extra weight and you need to reduce your calorie intake, you’re probably going to switch to more of these foods anyway. So it’s like it’s all this kind of mixed bag where things are kind of working together.
Aidan:
Yeah, that is also an interesting thing though, as you reduce your calorie intake, it also makes it a bit harder to get potassium [inaudible 00:15:04].
Because it doesn’t limit so much to the vegetable consumption, but it does limit these other things like these whole grains, even fruit to a certain degree.
Leah:
Nuts and seeds.
Aidan:
Nuts and seeds, all these things, it makes it a little bit harder, which is also part of why the DASH diet was not a weight-loss diet. It was just no overall approach. Which is also why in a lot of cases I make changes because a lot of people would be looking to reduce their body weight, which I guess we should talk about now. So body weight and blood pressure are pretty closely linked on average. A meta-analysis found that for every one kilo lost, in people who would have excess weight to lose or whatever you want to call it, every one kilo loss correlated with an average decrease of one unit of systolic blood pressure. So this could make a decent difference with a decent amount of weight loss. Even as little as, I know, 5% weight loss can make a pretty huge difference here.
Something that I definitely would’ve been going into this with a bit of a bias of many years ago when I was first looking into blood pressure was that body fat would be quite heavily associated with blood pressure, but people with higher BMIs who had a lot of muscle mass wouldn’t be, if that makes sense. I definitely went in it through that lens, but there is interesting research counter to that kind of bias just showing that BMI is actually more closely linked than body fat percentage. Body fat is a little bit more closely linked to higher blood pressure than muscle masses, but higher BMI matters more if that makes sense. And when you do think about it, it does make sense. Somebody who is exceptionally large is more likely to have high blood pressure, whether they’re lean or not. This is a complex topic talking about BMI in general, but if you do find somebody with a, say, a male with a BMI above 35 who is also lean, are they taking…
Leah:
Are they taking other things that would affect, yeah.
Aidan:
Are there other things like performance enhancing drugs or anything like that, that would affect it, which also raise blood pressure as well. Is there a higher likelihood of sleep apnea and stuff like that which could play a role in this too? There are a lot of variables, but it’s interesting knowing that even if I was relatively lean but at a high body weight and had high blood pressure, I’d probably still be looking to reduce weight a little bit just to reduce blood pressure if reducing blood pressure was my top priority.
Leah:
So we’re going to smash through some fairly easy ones now. So the next one is going to be reducing your cholesterol intake if it is already high. So higher cholesterol levels have been linked with higher blood pressure. The potential explanation for this is that the high cholesterol intake potentially leads to plaque buildup in the heart and then therefore increases blood pressure. Either way, looking at the research, we know the two are linked, high cholesterol levels and blood pressure. So if you have a high intake of cholesterol from animal-based foods, so higher fat meat products, eggs and dairy, and you’re wanting to reduce your blood pressure, it’s probably going to be a good thing to reduce these to a more moderate level and reduce your overall cholesterol intake.
Aidan:
My easiest hack that I’ve got is nitrate-rich food, particularly beetroot juice. I like to have easy hacks that people can just like do this-
Leah:
We love an easy word.
Aidan:
Yeah, do this one thing that’s not hard but has an impact, because there’s a lot of hard things in nutrition to do. So nitrate-rich food, basically nitrates dilate blood vessels and this helps blood flow more easily. Concentrated beetroot juice is the easiest way to do this. Most vegetables have nitrates, but we have to eat quite a large amount to get them. Even using beetroot as an example, I think to get the clinically best dosage, it takes about one kilo of beetroot to get that. That’s a lot, right?
Leah:
That’s a lot of beetroot.
Aidan:
But what if you juice it? Maybe it takes about 500 mil if you do that. What if you put it into a concentrated form? Now we’re looking at 60 mil or 50 to 60 mil. It’s a lot easier to have a shot that is 50 to 60 mil than it is to have a kilo of beetroot. On average, adding beetroot juice daily has been shown to reduce systolic blood pressure by five units on average. So that one thing does about half of what the DASH diet does, which is a complete dietary overhaul. This whole nitrates concept can be another reason why the DASH diet helps as well, because eating more vegetables will include more nitrates as well. It’s a nice easy one to do. It’s one that doesn’t work super consistently. There are some people who claim that beetroot juice only has an acute effect for a couple of hours. There’s other studies showing that if you do it daily, it does actually help a little bit more long-term. But I view it as an easy win that, best-case scenario, helps, worst-case scenario, you’re eating a micronutrient-rich food.
Leah:
Yeah, so there’s not really any losses to that.
Next one is going to be looking at reducing alcohol consumption or at least moderating alcohol consumption. So indirectly alcohol does contribute to just adding calories to your diet, so if that’s something that is a factor within your hypertension that could be playing a role. But there’s also other things that alcohol does like affecting your sleep for example, your intake of other foods. So just in regards to food choices that you’re making, maybe even higher sodium foods, less of those nutrient-dense foods that are nitrate, potassium-rich, but also just maybe the alcohol itself and its impact on the body. So a review found that those who consume high amounts of alcohol, this being classified as six or more drinks per day, and then decreased their intake by 50%, there was a reduction in systolic blood pressure by five units. So not as much as what we’ve kind of previously talked about with the DASH diet, but pretty significant amount if you’re going from six plus drinks per day is a lot.
Aidan:
It’s quite a lot.
Leah:
And then you’re just cutting it by 50%, so you’re still drinking a fair bit, and that can have a pretty significant impact on reducing blood pressure. The type of alcohol doesn’t appear to play a role here either. So I know there’s some talk around red wine having beneficial effects and within the Mediterranean diet and whatnot, but it seems that alcohol in general probably should be moderated. I don’t think that’s news to anybody, but particularly from a hypertensive perspective, it’s going to be a pretty effective.
Aidan:
Caffeine will probably be the last one we talk about. So I think a lot of people think about this with certain aspects, like pre-workout in particular, the supplement pre-workout just being like, is this detrimental for heart health or anything like that? But it’s often related to how we think about for blood pressure. Starting off, on average, we know the long-term impacts are likely not that detrimental. And we can also see this in just longevity kind of studies showing that on average people having somewhere between four and six coffees per day on average live a little bit longer. And there’s a lot of explanations for that. And it’s not just the caffeine aspect, there’s polyphenols, there’s a bunch of other stuff that is in coffee, but it’s like if this was dramatically increased in risk of high blood pressure leading to CVD outcomes, when we know that that is a big factor in longevity, we wouldn’t see this kind of outcome.
We know long-term it doesn’t seem to matter that much, it doesn’t seem to be affecting CVD risk that much. But we also know that caffeine can lead to an acute increase in blood pressure, in particular for people who are not habitual consumers of it, people who do not have high intakes of it regularly. And on average an increase can be pretty big, it ranges anywhere from three to 15 units, which is quite high at the top end of that and that can persist for a few hours. So it doesn’t matter much long-term, but if you don’t have caffeine regularly and you also have high blood pressure, I’d probably be pretty cautious of it.
Leah:
Yeah, 100%. So let’s wrap up with a little bit of a summary. So just kind of quickly going through main points that we did touch on. So things that you can do to reduce your blood pressure. So reduce sodium intake if it is excessively high, but also don’t go excessively low either. Implement elements of the DASH diet where possible, particularly increasing those nutrient-dense foods. Increase potassium intake through things like fruit, veg, legumes, nuts, seeds, dairy, et cetera. If you are overweight, potentially looking at reducing your overall body weight. Reduce cholesterol intake if it’s high. Eat some nitrate-rich foods on the daily. Potentially think about that beetroot juice supplementation. And limit alcohol consumption. So obviously there’s a lot you can do. They all have their place, but at the end of the day there is so much you can do. So this has been episode 72 of The Ideal Nutrition Podcast. If you haven’t already left a rating and review, it would be greatly appreciated if you did so, but otherwise, thank you for tuning in.