Foods to lower your cholesterol
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Hello and welcome to Zoe Shorts, the Bite Size podcast where we discuss one topic around science and nutrition. I'm Jonathan Wolf and today I'm joined by Dr. Sarah Berry. And today's subject is food to lower cholesterol.

So Jonathan, around half the adult population in the UK and the US have high cholesterol. And many people are completely unaware that they have high cholesterol. Medication to reduce cholesterol is projected to be worth almost $20 billion by 2027. Now, we all know that statins are one of the most prescribed drugs globally, but there may be other ways that we can reduce our blood cholesterol levels, specifically the food that you eat.

So Sarah, with your years of experience in the field, I'm sure you have some terrific insight into how dietary changes can reduce cholesterol. Yeah, there's some fabulous research out there showing just how much diet can impact our blood cholesterol levels. Then let's get into it.

Let's start with some really shocking numbers, Sarah. The World Heart Foundation states that high cholesterol causes 4.4 million deaths every year. That's around 7% of all deaths. So clearly, high cholesterol is a global health issue. Yeah, that's right, Jonathan. And beyond deaths, the latest data from America's Center for Disease Control and Prevention states that nearly 94 million American adults could be considered to have high blood cholesterol levels.

And I know we've discussed cholesterol before on this show, but if you're like me, you find it all a bit complicated. And about 10 minutes after Sarah explains it, you forget the whole thing. So Sarah, could you just start again and remind us what is cholesterol? So cholesterol is made in our liver and our bodies actually need it to produce things like vitamin D, bile acids, hormones, and also create all the new cells in our body.

And I know we discussed on a previous podcast that you can go and listen to if you're interested, that there is also cholesterol in some of the foods we eat. And we call that dietary cholesterol because it's cholesterol we get from our diet.

Now, Sarah, I might not have remembered all the details of how cholesterol worked, but I do remember that you explained on that podcast that the latest science actually shows that dietary cholesterol is not very important for affecting the cholesterol in our blood for most people. Yeah, that's right. Well remembered, Jonathan. Thank you, Sarah. Now, on that podcast, you also explained that some cholesterol is actually good while other cholesterol is considered to be bad. Can you explain this again?

So low density lipoprotein that we also call LDL cholesterol is your bad cholesterol and simply put this transports cholesterol from your liver around your body. You also have another type of cholesterol called high density lipoprotein also called HDL cholesterol which is your good cholesterol and again in really simple terms what this does is return cholesterol to the liver in order to be removed from the circulation.

And our bodies have a really complex process that maintains the balance of these good and these bad cholesterol in our blood for most people. Now, we do know that the ratio of good to bad cholesterol, and particularly the amount of bad cholesterol, so this LDL cholesterol, is really important in terms of our general health. And if we have high levels of this bad LDL cholesterol, that can contribute to things like hardening of our arteries and ultimately lead to heart disease.

Okay. I think I've got it this time, Sarah. So when we talk about reducing cholesterol, what we really mean is reducing this bad cholesterol, this LDL, while increasing the good cholesterol, which is the HDL in our blood.

Have I got that right at last? Yeah, well done. Top marks, Jonathan. All right. Thank you. I think it's important to emphasize to people not just to look, therefore, at the total cholesterol because a change in your diet might not show in a huge change in your total cholesterol, but you might actually see that you're reducing some of your bad cholesterol while slightly increasing your good cholesterol.

So can our diet change our cholesterol levels or are drugs really the only things that can have a big impact? So the best way to illustrate just how effective food and our diet can be at lowering cholesterol comes from the portfolio studies. And these are key nutrition science experiments showing the power of food in relation to our health.

And the concept of the portfolio diet isn't very straightforward. What you do is replace certain foods in your diet with other foods and ingredients that have been shown to lower cholesterol. And it's centered around four key elements. It's centered around soy protein, plant sterols, tree nuts and soluble fiber. And did it work? Absolutely. So it was shown to reduce cholesterol by 30%. Now, this is similar to the level of reduction that we see in cholesterol lowering from medication like statins.

So 30%, that sounds pretty incredible. So does Zoe recommend this diet to people with high cholesterol? So it is an incredible dietary pattern to follow, but there's a catch with a portfolio diet that it's really difficult to follow. So it's therefore more of a science experiment showing us what actually is the potential of food in terms of lowering cholesterol rather than something that's really practical, I think, in the long term.

Now, I think there's a more realistic dietary pattern that's also been shown to be effective in reducing cholesterol. And this is the Mediterranean diet. So I love the concept of the Mediterranean diet, which I think was invented by a bunch of nutritional scientists living a long way away from the Mediterranean, because I've spoken to a lot of nutritional scientists now, and every single one has a slightly different definition of what's in it, which is probably not surprising when you think that

People living in Italy and Greece and Morocco and Israel all think they're eating a Mediterranean diet. And if you go on holiday to these places, they're eating a very different diet. However, I think everyone agrees, Sarah, that it's about eating plenty of fruit and vegetables, sort of whole grains, nuts and olive oils. And then I think people start to argue a lot more about, you know, fish and lean meat and dairy products and the exact proportions.

Yeah, that's right, Jonathan. And while it's not quite as drastic at the portfolio diet in reducing your cholesterol, it's a really sustainable diet that lets you enjoy food that would be cut out if you followed a more restrictive diet like the portfolio diet.

And so Sarah, to be clear for people who are listening to this, while eating foods like eggs that are high in cholesterol won't necessarily raise your cholesterol, there really are foods that can make your cholesterol go up or down. And if so, can you explain what those foods are?

Yeah, so we know that actually dietary cholesterol, so cholesterol that's in the food that we consume, actually has only a really small impact on our blood cholesterol levels. But what we do know is that saturated fat rich foods and particular types of saturated fat actually can have quite a potent effect on raising our blood cholesterol levels.

And these are the kind of fats that are found in red meats, for example, lots of ultra processed foods such as pastries and also in some dairy such as butter. And what about carbohydrates? Because lots of people will be listening to this and saying, oh, well, so I've got high cholesterol, so I'm not going to eat any fat and therefore my cholesterol is going to go down, which sounds really logical. Is it correct?

No. So this is a big mistake, I think, that lots of people make. And unfortunately, there's lots of really poor misinformation out there around people with high cholesterol being told to follow a low-fat diet. What we do know is that if you consume healthy fats and healthy oils, you can actually improve your circulating blood cholesterol levels.

So rather than worrying about the amount of fat that you're consuming, you should be thinking about the types of fat. So the types of fat that we know, increased cholesterol, like I've just said, are the saturated fats. But we know that the poly and monounsaturated fats that are found in many vegetable oils, nuts and seeds, for example, can actually reduce our blood cholesterol levels significantly.

Now the problem is, is if you take out the fat from foods so that you choose low fat versions of foods, it's got to be replaced with something because fat is actually the component in food that gives the lovely creamy mouthfeel, it carries much of the flavour. So if you strip out the fat, you've got to replace it with something that still confers that nice mouthfeel and that great flavour to the food.

Quite often refined carbohydrates or sweeteners or other kinds of ingredients are added back into the food. And we know that these are really bad for us because we know that they impact your liver, which is involved in the production, like I said earlier, of cholesterol. But also they increase another type of fat that circulates in your blood, which is called triglycerides. And we know that this is really unfavourable in terms of cardiovascular disease if it's elevated as well.

Amazing. Thank you, Sarah. So I think now that we understand a bit more that what we eat can cause high cholesterol and it could actually be a carbohydrate or a fat, can you be a bit more specific about what a listener should do to change their diet if right now maybe their doctor has told them that they have high cholesterol or they know that it's in their family? And are there any sort of smart swaps that they could do without completely changing the way that they eat?

Absolutely. And I think it's making simple smart swaps, as you call them, Jonathan, that are personalised to your body, but also your preferences that are ones that people will most likely stick to and therefore lead to sustained improvements in blood cholesterol. And actually, your blood cholesterol can change really quickly from dietary changes. So we see changes in our studies as little as 10 days to 14 days in blood cholesterol. So the

that should really motivate people that you know quick changes but sustainable changes will really have an impact. And the kind of things that you could do is to try and eat less red meat and less processed foods because these have the types of fat that we know increase your bad cholesterol. You could introduce many fibre-rich foods such as beans and vegetables and also plant-based protein sources that we know will lower your cholesterol.

And spreads are also a good substitute for butter since most spreads are made from vegetable oils. So they contain these healthy, unsaturated, good fats that I've talked about, the poly and monounsaturated fats. Although, Jonathan, this is quite a controversial area.

And I remember from our previous episode that many of the foods that are high in cholesterol are also high in saturated fat. And this may have led to some of the previous misinformation suggesting that it's the cholesterol in some food, such as red meat, that explains why red meat, for example, is bad for us. Yeah. And with regards to cholesterol, Jonathan, saturated fats are what's increasing the bad cholesterol in our blood, not that dietary cholesterol. Yeah.

Yes. And so there's sort of, there could have been this confusion, right? When they looked at it, because some of those foods happen to have high cholesterol as well. And so we now understand, I think this is right, Sarah, like we understand better the mechanisms today and therefore, you know, the high cholesterol in the,

egg or the meat is no longer being blamed for it, but actually the red meat still in the dock, still in trouble. We just understand that it's sort of different properties of the red meat that are causing us problems. Absolutely. So if we think of liver, for example, liver is high in cholesterol, but also high in saturated fat. If we eat lots of liver, we'll have an increase in bad cholesterol, but it's actually not the cholesterol in the liver that's going to cause this. It's the saturated fat. Music

Well, look, Sarah, I think it's a brilliant way to come around. And we've had a slightly longer podcast than usual because I think it's such an important topic and it is complicated. If you're going to sort of sum this up for somebody listening and saying, OK, so I am worried about my cholesterol, you know, what should they do?

So I think that there's really clear evidence to show that our diet can significantly alter our cholesterol. There's clear evidence to show that it's the type of fat that's important and not the amount of fat that's important to consider. So please don't follow a low-fat diet, but please change to really healthy oils. And also be motivated in knowing that a dietary change can actually induce a change in your cholesterol in as little as two weeks.

And I'd like to pick up on the first part of what you're talking about, which is sort of the misinformation. And it's something I've talked about before, that when I was growing up, my dad was told that he had very high cholesterol. He was living in the States at the time, and he was told to eat a very low fat and therefore, of course, very high carb food.

diet. And I think today, you know, we know, you know, every nutritional scientist I talked to says, oh yeah, we know that isn't the right advice. And yet I still hear stories from friends and family that, you know, they get a note from their physician, you know, the NHS here in the UK, whatever it is saying, uh, you know, you've got a high cholesterol and therefore here's this guidance on what you should eat. And it's basically saying you should be eating all of this low fat, um,

food, you should be avoiding all of these high fats, you know, like olive oil and nuts and things like that. What's your take on this, Sarah? My thoughts are that's the wrong advice to be giving to people. We now clearly know that the amount of fat in our diet is not what the problem is. It's the type of fat that's the problem. And pushing people to high carbohydrate diets, we know is really not good for our heart health.

So anyone that has high cholesterol, I would really encourage you not to cut down the amount of fat you're consuming, but I would encourage you to think about the type of fats. And so this takes us back to what we mentioned earlier. So increasing the amounts of these healthy oils, so the mono and polyunsaturated oils, so these are vegetable oils, extra virgin olive oil, and reducing the saturated types of fat that you find in, for example, ultra processed foods and red meats.

Thank you, Sarah. And just before I wrap up, I'd really love to talk about individually personalized responses. I think one of the things we do in this podcast, we try really hard to make sure that all the advice is sort of available for everybody and don't say, hey, you have to go and do these tests. But I think in this particular case,

it feels wrong not to talk about the differences that we see because I think they're just so striking. And I guess we've had more than 50,000 people do these tests, which I think, Sarah, you can describe in a minute, which is the same as the tests we originally did on sort of thousands of people in these labs, where we look at your responses to the sort of standardized meal. And we see this amazing variation in response to high fat meals, which seems to have some very big implications for what's right

you know, for me as an individual. Could you maybe touch on that a little bit and explain what's going on there? Yeah, so one of the things that we test at Zoe is people's blood fat responses to a high fat meal. So we give people these muffins that contain 50 grams of fat and we look at how quickly and for how long circulating levels of blood fat change.

And we measure this from a measure called triglycerides. And what we know is that the fat in the meal that we consume increases the levels of blood triglyceride levels. And...

We know that people respond hugely differently in terms of how much their triglycerides go up and how long they stay elevated. This is even despite them having exactly the same meal to other people. And we see about a tenfold difference in how one person responds versus another person responds.

And we know this is down to loads of different factors. We know that it's partly down to our genetics. We know it's partly down to our gut microbiome, which are the trillions of bacteria that are living in our gut. We also know it's partly down to our age or our sex or even how much we weigh. But there's loads of different factors that shape how we respond to high-fat foods and how our circulating levels of fat change following us consuming these high-fat meals.

And I think what's interesting is it's not just if you have high cholesterol, therefore you're in the third of people who have this bad response, or if you have low cholesterol, you're definitely in the good response. Actually, it's very different. So basically without doing this test,

You don't really know what's going to happen. Obviously, you know, there are people who have very high fasting fat levels and they're probably, you know, so you have some idea of certain people. But in general, this response to food is actually a sort of different measure, isn't it, than just the high cholesterol levels that you would get tested by your doctor? Yeah.

Yeah. So when you go to a doctor and they test your cholesterol levels, they actually do what's called a full lipid test. And that isn't just your cholesterol. So it isn't just your HDL and LDL cholesterol. They also always test something called your triglycerides. And we know that triglycerides are equally as important as cholesterol is in our health.

And this is something that's been really understudied. And it's really interesting because we know that diet can play a huge role in changing our triglyceride levels. And this is what we've been testing a lot with the work that we've been doing at ZOE.

And I think for me, you know, this is one of the big takeaways in the same way we talk a lot about blood sugar, which is, as you understand your own sort of fat control, it has a lot of influence on what you do. It doesn't mean you need to give up fats. You know, olive oil is extra virgin olive oil is generally good for everybody.

But certainly thinking about the amount that you want to take and certainly thinking about what's going to happen if you're starting to eat these less healthy fats, you see this very big change. And so you could have somebody actually who has high cholesterol, but actually whose fat control is pretty good. They're told to move to this low fat diet. And actually they swap. They've been able to deal with this fat. Well, it turns out actually their blood sugar control is really bad.

and they're switching something that's much, much worse, right? That their liver is then struggling with and it's really terrible advice. And so I think it is one of the most striking things that's come out of Zoe for me over the last five years. Yeah, if there's one thing that I could say to people is do not go on a low-fat diet.

Amazing. And we've been lucky to have one of the world's foremost experts on fats and nutritional science today, Sarah. If out of today learning more about cholesterol means you'd like to understand more about the right diet for you based upon how your body responds to food, you might want to try Zoe's personalized nutrition program to improve your health. And if so, you can get 10% off by going to joinzoe.com slash podcast. I'm Jonathan Wolfe. And I'm Sarah Berry. Join us next week for another Zoe podcast.

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