Reversing atherosclerosis with diet | Simon Hill, Msc

Is it possible to reverse atherosclerosis through diet or supplements? And if so, what results can we expect to see? This is a question that's been landing in my inbox almost daily since I shared my own coronary CT angiogram results a few months back. And to be honest, I've been wondering the same thing. Many of us, including me, are finding out that we have some degree of plaque buildup in our arteries. And it can feel intimidating, especially when you feel like you're doing all the right things, like eating nutritious foods and staying active. The last time I did a deep dive on this research on this topic was back in 2019 when I was researching for my book. Since then, even more clinical trial data has been published. Actually, some really, really high-quality trials have come out. So today we're going to look at all of this data, new and old, focusing on whether or not diet can reverse atherosclerosis. I know your time is incredibly valuable. So today, without turning this into a one-hour-plus episode, here is what you will learn. What atherosclerosis is and how it can show up in your life. Various tools to measure plaque and atherosclerosis, some of which you may want to discuss with your doctor so you can see your own plaque levels. The six major randomized controlled clinical trials that have asked the question, "Can diet reverse atherosclerosis?" And to wrap things up, I'll share my thoughts on what I think is worth implementing or at least exploring in our own individual lives based on this evidence. As always, I'll link to each of the studies covered today in the show notes. So if you want more information or want to verify the things I am saying are true and accurate, then you can do so in your own time. Before we get into it, a quick request from me, if you're getting value from these videos or podcasts, the best way to support the show is to hit subscribe on YouTube or follow on Spotify and Apple podcasts. All right, let's get to the bottom of this. Is it possible to reverse atherosclerosis through diet? First things first, you might be wondering what exactly is atherosclerosis? It's a bit of a mouthful. What is he talking about? Atherosclerosis is a chronic progressive disease. It happens when plaque builds up in your arteries. These plaques are fatty deposits and they're made up of cholesterol, immune cells, calcium, and other fibrous tissue. The risk factors driving atherosclerosis are something that I've talked about at length in previous episodes and are not really the focus of this episode. But in short, the key thing I want you to know here at the top of this episode is that atherosclerosis is not an inevitable part of aging. It is in fact a disease process that is downstream of our normal physiology dictated by your genes and the environment you live in and the lifestyle choices that you make. Genes aside, some of the major risk factors are elevated blood pressure, smoking diabetes, fatty liver disease, and dysliperdemia or elevated APOB. Your arteries are very important. They distribute oxygen-rich blood to key organs throughout the body. Think of plaque like a slow growing scab inside your artery wall. When it comes to this scab, there's a little bit of nuance to appreciate. We have two main types of plaque. Soft plaque, which is thought to be the most vulnerable and most dangerous plaque and hardened or calcified plaque, which is more stable but still can be problematic. And usually a sign of someone having had this inflammatory process, occurring in their artery wall for a significant amount of time. You don't go from a healthy blood vessel to having calcium deposits in the artery wall overnight. So what's the problem with this plaque? Well, over time, as more and more plaque accumulates, your arteries narrow. Imagine trying to drink a thick smoothie through a straw. Now imagine that each morning, the straw that you're drinking the smoothie through gets more and more narrow. It's going to be more challenging and requires more effort to get the smoothie flowing through the straw and into your mouth. That's essentially what's happening to blood flow through the arteries. They become more and more narrow over time as plaque builds. Eventually, the straw will become so narrow that you can't drink any of the smoothie. Similarly, this problem becomes serious when the artery cannot deliver enough oxygen-rich blood to your heart, brain or other organs. And if a plaque ruptures, think of it like a blister popping inside your artery, it can trigger a clot that completely blocks blood flow. That's what's typically responsible for a heart attack or stroke. As was the case when my dad had a heart attack at age 41. The reason I'm making this video and continue to talk about this topic is because of the silent nature of this disease process. Unless you're actively checking in on key markers, you might not know that any of this is happening until the event occurs, which is what happened to my dad. And for many people, that first event is either fatal or results in lifelong disability and a dramatic reduction in quality of life. This is why reversing atherosclerosis, reducing that plaque buildup, or at least stabilizing the plaque that exists in your arteries matters so much. We're talking about more time with your family, more adventures, more memories, more love, more time to enjoy the human experience that we've all been gifted. In order to understand how medicine and lifestyle changes affect plaque, we first need to be able to measure it. Otherwise, how would we know if things are getting better, worse, or staying the same? Let's run through the main ways that doctors and researchers do this. The first one you've probably heard me mention before is a coronary artery calcium score or a CAC score. This is just a CT scan of your heart that looks for calcium in your arteries. If your score comes back as zero, that's great news. Your short-term risk of a heart attack is very low. But here's the catch. This scan only sees calcified plaque, not the softer, more vulnerable plaque that can be prone to rupturing. Calcim tends to show up later in the disease process. So a zero score is much more meaningful in people that are aged over 40. For example, if your 70 and your CAC score is zero, that is outstanding. If your 30, it doesn't mean much. At that age, we'd expect a zero score anyway. One of the real advantages of this test is that it's been studied extensively. We have loads and loads of data linking coronary artery calcium scores with future cardiovascular event risk. That makes it a very useful tool in clinical practice. Another method used to measure plaque is called the carotid intamumidia thickness or IMT. Here an ultrasound probe is placed on the side of your neck and it measures the thickness of your carotid artery wall. This is clever because it can pick up early changes in the artery wall long before calcium shows up. That said, it's not used as much in day-to-day care because the measurements can vary a bit depending on who's doing the scan. So it is more of a research tool than a routine clinical one. Then we've got the CT angiogram or CTA. This is what I had done myself. I shared those results in episode 372. It's a step up in detail compared to a coronary artery calcium score or IMT. A CTA shows the total amount of plaque that you have, what it's made of, whether it's soft or hard, and whether it's actually narrowing your arteries. It's considered non-invasive. Yes, you need an IV line for the contrast die, but it doesn't involve threading a catheter into your arteries like some of the older methods. And with new AI tools, like those from clearly health, the scans can now be analyzed in even more detail. This has actually been used in clinical trials right now to track how plaque changes over time with different treatments. And finally, there's invasive angiography or quantitative coronary angiography, QCA, the traditional gold standard for measuring plaque. This one really is invasive. A catheter is fed through an artery in your wrist or growing into the coronary arteries themselves, dies injected, and x-rays are taken, which are then analyzed by various software. Importantly, it measures the diameter of the lumen or inside of the artery, from wall to wall, not total artery wall thickness or the plaque volume hidden within the wall. Because arteries can remodel outward, what's called positive remodeling, you can have a lot of plaque building up in the wall without much change in lumen diameter. It is however very precise for spotting areas of an artery that could be restricting blood flow. And the key advantage is that if the cardiologist sees a blockage, they can treat it right there and then with a stent or a balloon. The downside is that it's a procedure with risks, so today it's mostly used when doctors expect that treatment might be needed. For more stable patients, we usually start with the less invasive tests that I just walked you through. And as you'll see, shortly, whereas this QCA was used in clinical trials back in the 90s, it has fallen out of favor now with these more modern and less invasive tools becoming available. All right, let's dive into the meat or should I say the vegetables of today's episode. As I mentioned at the top of this episode, we're going to focus on six randomized controlled trials. These are the highest quality nutrition studies that we have available to us today when it comes to understanding diet and atherosclerosis. Three of them were done back in the 1990s and used quantitative invasive of angiography to measure changes in plaque. The first is Dean Ornish's lifestyle heart trial, which was conducted in 1990, and then the stars trial conducted in 1992, and then two years later again, the Scrip trial. And from there we move forward in time. We've got two more recent trials that used corroded intima-media thickness or IMT ultrasound, the Predamette study from 2013, and Cordia Prev from 2022. And finally, one trial, the Disco CT trial that was published in 2020 that used coronary CT angiography with the clearly AI analysis. So that's out to rain today. Six randomized controlled trials that ask a critical question, can nutrition affect atherosclerosis? And more importantly, can it actually shrink existing plaque? We'll go through each of these one by one in the order that they were published. But before we get there, I want to address something that I know many of you are already thinking and may comment in the comment section on YouTube. And that is what about other studies? What about Dr. Esselstens work? Didn't he show reversal of cardiovascular disease with diet? These studies are important to acknowledge, but here's the key. I have chosen randomized controlled trials for good reason. They give us the greatest possible chance of seeing the independent, the independent effect of diet on atherosclerosis studies like Dr. Esselstens and other case series. They are interesting, but they're not randomized controlled trials. They don't have a formal control group. And without a control group in play, we simply cannot know whether the diet itself calls changes in plaque. Take Dr. Esselstens study, for example, many of the participants who change their diet were also on lipid lowering medications. So was it the diet or the medication that drove the changes without a group of people on the same medications, but eating a different diet, we have no way of knowing. That's why randomized controlled trials are considered the gold standard. And now that we've cleared that up, let's go through these six studies. I've been using Woop for over six years and I can confidently say it keeps me on track when it comes to my sleep and exercise routines. The next generation of Woop isn't just tracking your workouts. It's monitoring your sleep quality, your recovery state, and even giving you insights into your biological age. No screen, no distractions, just continuous data on what your body actually needs. And here's what matters. Daily Woop, where is linked to increased physical activity, to better sleep, and improved heart rate variability. I have no doubt that my Woop is helping me train smarter, recover faster, and make decisions that support my long term health. Head to join.woop.com forward slash Simon. That's join.woop.com forward slash Simon to get one month off your first subscription. First up, the lifestyle heart trial. A groundbreaking study led by Dr. Dean Ornish. It was published first in 1990 and then it was followed up in 1998 with more data. This was one of the first controlled studies to give us actual angiographic images. Real pictures of the arteries showing that atherosclerosis might be reversible with lifestyle changes. And importantly, without medication or surgery. At the time, this was a revolutionary idea. And honestly, it's not the kind of study that could be done today. I'll explain why in a moment. So who was in this study? There were 48 patients, mostly men, or with moderate to severe coronary artery disease. To get in, you needed at least one artery that was narrowed by 50% or more, and evidence of a schemia. So we're not talking about people with just a little bit of plaque. Out of those 48, 38 in the intervention group and 15 of 20 in the control group. So we're not just talking about people with just a little bit of plaque. Out of those 48, 35 made it through to the trial, 20 of 28 in the intervention group and 15 of 20 in the control group. Now, what did the intervention group actually do? What did the intervention consist of? They all went on a very intensive lifestyle program, which meant a whole foods vegetarian diet, very low and fat, less than 10% of calories from fat, avoiding simple sugars, and instead focusing on complex carbohydrates from fruits, from veggies, from grains, and from legumes. Daily moderate aerobic activity, things like walking, stress management every single day, yoga, breathing exercises, meditation, etc. Weekly group support sessions and smoking cessation, though only one person was smoking at baseline, and they quit when the study started. So that probably wasn't a major factor here. The control group on the other hand just received standard care. That included the usual dietary advice of the time, but no structured program like the intervention group. Now, here's the reason that this study probably wouldn't happen today. All participants had to agree not to take lipid-loring medications like statins during the trial. That was true for both the intervention group and the control group. Other drugs for and Jaina, blood pressure, things like that were allowed, but not statins or lipid -loring medications. And given what we know about the effectiveness of these medications today, it would be considered unethical to run a trial in people with moderate to severe heart disease and not let them use them. So what happened in this study? What were the results? After one year in the lifestyle group, the average stenosis, which means the narrowing of the arteries, improved by 2.8%, which was a 6.7% relative improvement, again only after one year. In the control group, that stenosis worsened by 3.9%. LDL cholesterol dropped by about 40% in the lifestyle group compared to just 1.2% in the control group. Now, just to be clear, when I say regression here, what they were really measuring was the lumen diameter using that quantitative coronary angiography or QCA. If we are being accurate and technical here, this is a surrogate marker. QCA can't tell us everything about Placburden the way that today's imaging can. And the best way I think to picture this is like a garden hose. QCA measures the width of the opening, the space where the water can flow. But it doesn't actually tell us how much gunk is stuck to the inside of the walls. Because sometimes the hose wall thickens on the outside. And arteries can do the same thing. They can expand outward, hiding plaque that's building up within the wall. That said, when you combine this lumen improvement with the 40% reduction in LDL and the lower number of cardiovascular events in the intervention group, the evidence is strongly suggestive that real regression of atherosclerosis probably did occur. So pretty striking results after just one year. But the five year data was even more interesting. The lifestyle group showed an average stenosis improvement of 9.7% and the control group, their stenosis worsened by 27.5%. And here's the kicker. The participants who stuck closely to the lifestyle protocol actually saw their stenosis improved by about 17%. That's a huge shift. Now let's talk about medications. Between years one and five, many of the control patients actually started taking lipid lowering therapy, nine out of 16 to be precise. So about 60% of them, whereas no one in the intervention group started taking lipid lowering medications. And this gave us a very interesting secondary analysis. In the control group, those who were on lipid lowering medications, they still got worse. Their stenosis progressed by about 6%. But those in the control group not on meds got much worse progression of around 19%. So here's the takeaway from that. Lifestyle changes on their own outperformed usual care. Even when usual care included medications. At the same time, they slowed the worsening compared to those not taking medications and not making lifestyle changes. I mentioned the intervention group had a reduction in events. Let's look at actual cardiovascular events from the study because that is what really matters. In the control group, 20 participants experienced a total of 45 events. That's more than two events per person. In the lifestyle group, 28 participants experienced 25 events. That's less than one event per person, a massive difference. So what do we learn from Dean Ornish's lifestyle heart program from this study? Firstly, adopting a very strict lifestyle regimen. It didn't just slow atherosclerosis. It seemed to reverse it. And it also meant that people were much less likely to suffer from and experience a cardiac event. And one last important point. Some people use this study to say a vegetarian diet alone can reverse atherosclerosis. But let's be careful. That's not what this study shows. This intervention was multi-pronged. It wasn't just diet, it included exercise, stress management, meditation, group support, and diet combined. We don't know how much each individual piece of that intervention contributed to the changes in stenosis and the cardiovascular events. What we can say is this, the overall program was extremely effective compared to standard care and the benefits were even greater for those that really stuck to it. And if anything, the best results might come from layering lifestyle changes with medications, but that would have required a third study arm to prove. Next up, the STAR study from 1992. That's the St. Thomas atherosclerosis regression study. This one was published in the Lancet Journal and it was considered a landmark trial because it asked a very big question. If you lower cholesterol with diet or medication, can you actually reverse coronary atherosclerosis? They enrolled 90 men with established coronary heart disease and pretty high cholesterol around 280 milligrams per desioleta. And their participants were assigned randomly to one of three groups. Group one, a cholesterol lowering diet. This was a low fat diet, low in dietary cholesterol. It had an emphasis on fruits and vegetables and cereals and fish and reductions in red meat, full fat dairy and eggs. And then group two, the same cholesterol lowering diet, but this time combined with collis stiroming, which is a bile acid sequestrant and older LDL lowering drug that works by reducing bile reabsorption in the gut. And then group three, routine medical care, meaning no special diet, no lipid lowering drugs, just whatever their doctor would normally recommend. The researchers followed these men for just over three years and they used quantitative coronary and geography again. So, lumen measurements here to see how their arteries changed over time. Here's what they found. Total cholesterol levels stayed high in the usual care group, about 268 milligrams per desioleta. The diet only group lowered theirs to about 238 milligrams per desioleta. And then the diet plus collis stiroming group dropped the furthest. Their total cholesterol dropped to around 215 milligrams per desioleta. Now, you'll notice I'm saying total cholesterol here, not LDL cholesterol or APRB. That's because in the UK in the early 1990s, LDL and APRB just weren't commonly measured or reported in clinical trials. Total cholesterol was the standard. We've come a long way since then. But given the diet and collis stiroming both work primarily by lowering LDL, we can be confident that the reductions were driven mostly by LDL cholesterol. When you're starting a new business, it knows that you are wearing a lot of hats. You are finance, you are marketing, you are operations, you are logistics and customer service all at once. Finding the right e-commerce solution that actually makes your life easier and takes some of that heavy lifting of your plate is absolutely key. So you can focus on growing the business instead of managing tech. That's where Shopify comes in and that's what we use at 38 Terra. Shopify is the commerce platform behind millions of businesses around the world, powering about 10% of all e-commerce in the United States, from household names to brands that are just getting started, like 38 Terra. 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So what happened to atherosclerosis in these subjects? In the usual care group, nearly half, 46% showed progression and only 4% showed regression. In the diet only group, just 15% progressed, while 38% regressed. In the diet, plus drug group, 12% progressed and 33% regressed. When you look at the actual vessel measurements, the usual care groups arteries actually narrowed. The diet only group stayed about the same and the diet plus drug groups arteries actually widened, which was evidence of regression. Specifically, the mean-changing lumen diameter reduced by about.2 millimeters in the control group, meaning the arteries narrowed. Reduced by about.03 millimeters in the diet only group, meaning the artery diameter was essentially stable and increased by.1 millimeters in the diet plus polystyrene group, meaning the arteries widened. And clinically, both intervention groups had fewer cardiovascular events compared to usual care. Now there are a couple of caveats here that are worth pointing out. The study only included men, so we can't just assume the same results would also apply to women. We used polystyrene, not statins, so the drug arm doesn't directly translate to today. But here's why stars was so important. It showed that dietary changes alone reduced progression and increased regression in a substantial percentage of patients, and combining diet with medication gave an even greater benefit, actually increasing the diameter of the artery in many cases, which probably explains the lower event rate that was seen in this group. Even back in 1992, stars made it clear. Collestral lowering interventions, diet drugs, or both, could not only slow atherosclerosis, but seemingly reverse it by opening up narrowed arteries. Two years later, in 1994, we got the script study, the Stanford Coronary Risk Intervention Project. This one was ahead of its time because it didn't just look at diet or one drug, but tested whether a comprehensive lifestyle intervention, alongside medical care, could slow down atherosclerosis better than standard care alone. Then, around 300 adults, average age, mid-50s, most of them were men, or with coronary artery disease confirmed by angiography. About half of these were then randomized to the intensive lifestyle risk reduction program, and the other half randomized to standard care. The lifestyle group got the full package. They got a low fat, low cholesterol diet, very similar to the one used in stars, more fruits, vegetables, grains, and fish, less red meat, dairy fat and eggs. They also got exercise prescriptions, weight loss guidance, and smoking cessation support. And importantly, very importantly, unlike Dean Ornish's study, they also got lipid-lowering medications when needed, whereas the control group continued with standard medical care from their own doctors without that structured program. And again, same as the previous two studies that we've gone through from the 1990s, they used quantitative coronary angiography to measure the minimum artery diameter at baseline and again, after four years. And here's what they found. After four years, the rate of artery narrowing in the lifestyle group was 47% less than in the usual care group. And as one might expect, risk factors improved across the board in the lifestyle group. LDL cholesterol and APRB dropped significantly, HDL rose, triglycerides fell, body weight dropped, and exercise capacity improved. And here's where you can see how lipid science evolved quickly in just a couple of years. Unlike stars which reported only total cholesterol, by 1994 in California, they were measuring LDL cholesterol and even APRB, which gave a much clearer picture of how the interventions were affecting the particles that actually drive plaque build up. Most importantly, hospitalizations for cardiac events were far lower. 25 hospitalizations in the intervention group versus 44 in the usual care group. That's nearly a 40% lower risk of being hospitalized with a cardiac event. Death rates were low in both groups with three deaths in each. Now, were there limitations within this study? Sure, like most studies. Firstly, just like the lifestyle, heart trial, it was a multifaceted intervention. So we can't say with any confidence whether the diet that meds the exercise or the smoking cessation mattered most. It was likely a combination and the population was almost 90% men. So again generalizability to women is limited bit of a recurring theme for the studies that we've been through so far. But the key takeaway is clear. Script showed that when you put risk factor management together, diet, exercise, smoking cessation and appropriate medications, you can significantly slow atherosclerosis progression and reduce cardiac hospitalizations compared to usual care. At least according to quantitative coronary angiography, which again measures lumen diameter as a surrogate for atherosclerosis rather than directly measuring plaque burden. Now we fast forward a couple of decades and we land in Spain where the Predimid study, study four in this episode today was carried out. This was a massive multi-centre trial designed to test whether a Mediterranean diet that was supplemented with extra virgin olive oil or mixed nuts could reduce major cardiovascular events. And in this study, they enrolled over 7,000 individuals aged 55 up to 80 and about 57 percent of them were women. These weren't healthy people plucked out of the general population. They were people that were at risk of cardiovascular disease. Everyone either had type two diabetes or at least three other risk factors like hypertension, smoking, elevated LDL, obesity or a family history of heart disease. But importantly, none had diagnosed cardiovascular disease at the time of enrollment. The participants came into this study and were randomized into one of three groups. The first group were randomized to a Mediterranean diet with added extra virgin olive oil. The second group were randomized also to a Mediterranean diet, but with added mixed nuts. And then the third group, which was the control diet, was given a low fat dietary intervention. Both of the Mediterranean diet groups were encouraged to eat plenty of olive oil, fruits, vegetables, cereals, legumes and nuts. They could have fish and poultry in moderation. But their diets were low in red meat, dairy and sweets. To keep people engaged to participants in the Mediterranean groups received regular education sessions. And we're actually given free supplies of either olive oil or nuts, depending on which of those two groups they were randomized to. Now a lot has been made of the control group in this study with many claiming that they didn't actually adopt a low fat diet by definition. And that's true. The real difference in this study wasn't the total amount of fat in the three groups. That ended up being pretty similar, but it was actually the quality of fat that they consumed. The Mediterranean groups were eating more unsaturated anti-inflammatory fats from olive oil and nuts. While the control group slightly reduced fat, but replaced it mainly with starches and lost out on the extra heart healthy unsaturated fats. The median follow-up was just under five years, but the trial was actually stopped early because the benefits were already so clear that it wasn't ethical to keep withholding the intervention from the control group. Specifically, here's what happened. There were 288 major cardiovascular events across the entire study. The Mediterranean plus olive oil group had 96 events, 3.8%. The Mediterranean diet plus nuts group had 83 events, 3.4%. And the control group had 109 events, which amounted to 4.4% of the people in that group having an event. In terms of risk, both Mediterranean diet groups came out about 30% better than the control group, a 30% reduction with olive oil and a 28% reduction with nuts. And just like in Ornish's lifestyle, heart trial, in this study adherence mattered. Those who really stuck with the diet in the intervention group saw a 58% lower risk of experiencing a major cardiovascular event. That's massive, but there's more. A sub-study of 164 participants looked at imaging outcomes, specifically the internal corroded intramamedia thickness or IMT and plaque height. After about 2.4 years, the control group on the low fat diet showed progression of IMT and plaque height. Basically, their arteries were getting worse. In the Mediterranean plus nuts group, IMT and plaque height actually regressed, suggesting improvement in atherosclerosis. In the Mediterranean plus olive oil group, there was no sign of regression, but importantly, there was also no progression. So in terms of imaging, the nuts group seemed to experience some regression. There were signs of regression while the olive oil group showed stabilization. Now, before anyone crowns nuts as the winner over olive oil in this study, it is very important to point out that there was no significant difference between the two Mediterranean groups in plaque volume or in cardiovascular events. This sub-study was small and it wasn't designed to compare the two Mediterranean diet interventions directly. And coming back to the main trial, both groups had very similar reductions in major cardiovascular events, which, let's be honest, is what really matters to most people, including you and I. All right, story time. Years ago, in my early 20s, I spent a fair amount of time in China, in Sri Lanka and India. I would go there and I would visit tea regions, I'd sit with growers, and learn how different teas were actually grown and prepared, and how different they could be nutritionally. That's where I first fell down the rabbit hole with poo air tea. I loved the flavor, but what really stuck with me was how this tea made me feel grounded, steady, and energized in a calm way rather than jittery. Poo air teas are naturally rich in polyphenols, including catechins, plant compounds that have been widely studied for their lengths to long-term brain, cardiovascular, and metabolic health. 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Whereas function makes it $365 a year, literally $1 a day, for ongoing access to your biomarkers and personalized insights based on your unique results. All tracked securely on the function platform. This new year give yourself the gift of clarity, understanding what's actually going on inside your body and making evidence based lifestyle changes from there. Learn more and join using my link at functionhealth.com/simonhill and use the gift code Simon25 for a $25 credit towards your membership. That said, I would love to see this explored in further studies. While there is a strong mechanistic reason to say that nuts are better than olive oil for shrinking plaque, nuts do bring in a unique package of nutrients that olive oil does not. Things like plant steriles, arginine and fiber, all present in much higher amounts in nuts could at least in theory be particularly effective at reducing atherosclerosis. So what's the main takeaway from the Predymet study? Adopting a Mediterranean style eating pattern reduced cardiovascular events in high risk individuals by around 30% compared to commonly prescribed low fat diets. And in this smaller sub-study, it slowed and in In some cases, slightly reversed. the progression of atherosclerosis as measured by corroded intima media thickness. Importantly, this was the first primary prevention randomized controlled trial showing that diet alone without lipid lowering medications, and people at risk of cardiovascular disease but who hadn't yet had an event could actually change the rate of plaque progression in their artery walls. While we're on the topic of the Mediterranean diet, let's look at our fifth study today, Cordia Prov. This was another Spanish study that evaluated whether a Mediterranean diet rich in extra virgin olive oil could reduce atherosclerosis progression. But unlike prediumed, this trial was conducted in participants who already had established coronary heart disease, not just those at high risk. So this is considered a secondary prevention study. The key question that the researchers wanted to answer here was, can a Mediterranean diet rich in extra virgin olive oil reduce the progression of atherosclerosis compared to a low fat high carbohydrate diet in people with established heart disease? This analysis included 939 Spanish adults aged 20 to 75 average age around 60 years old, 82% were male, and 54% had type 2 diabetes. Many were overweight or obese, and most were former smokers. Importantly, many participants were already on lipid lowering drugs, including statins, as well as anti-diabetic and anti-hypertensive medications at baseline at the start of the study. The researchers accounted for statin use for the use of lipid lowering medications when analyzing the results, so we know that these medications were present and controlled for statistically in this study. Participants were randomly assigned to one of two groups. The first group followed a Mediterranean diet with about 35% of calories coming from fat, heavy on extra virgin olive oil. The other group, which was the control group, followed a low fat diet with less than 30% of calories from fat, and more than 55% of calories from complex carbohydrates. Both groups received regular counseling from registered dietitians. The researchers measured corroded intramamedia thickness, IMT, at baseline, at five years, and again at seven years. They also looked at corroded plaque number and maximum plaque height over time. The Mediterranean diet group showed significant decreases in corroded IMT after five years, and after seven years. Both changes were statistically significant. Meanwhile, the low fat group showed no significant change from baseline in their corroded measurements. The Mediterranean group also had significant decreases in plaque height and overall plaque burden compared to the low fat group throughout the follow-up period. And remember, while plaque build up measurements of plaque are interesting, it's not the most important outcome. The main choreo prep study also tracked actual cardiovascular events, the risk of someone having a heart attack or having a stroke, etc. Major cardiovascular events occurred in 87 participants in the Mediterranean group versus 111 in the low fat group. That's about 28 events per thousand person years in the Mediterranean group compared to nearly 38 in the low fat group. After adjustment, following the Mediterranean diet, reduced cardiovascular event risk by 25 to 28%. Now, you might be wondering how well the low fat group actually stuck to their prescribed diet. They were advised to eat less than 30% of calories from fat, but in reality, they ended up averaging closer to 32 to 34%. The Mediterranean group, by contrast, averaged 37 to 39% of calories from fat with much more of that fat coming from extra virgin olive oil, and other monounsaturated fat-rich food sources. So while both groups kept saturated fat low, the real difference was in the quality of fats, again, just like predimed. More olive oil, nuts, and fiber in the Mediterranean arm versus more carbohydrate, including refined carbohydrates in the low fat arm. And I'd argue that this isn't really a limitation of this study. It's actually a strength because it shows us what happens in the real world when you prescribe someone a low fat diet. Very few people ever managed to get below 20% of calories from fat, like you sometimes hear about online. Instead, people usually hover around the 30% of calories from fat, exactly as we saw here in this study, and similar to what we saw in predimed. And that makes these findings much more representative of real world dietary patterns and the likely effects that people are going to get by adopting a Mediterranean diet or a low fat diet. It's one thing to talk about extremely low fat diets hypothetically on the internet. It's another to see how they play out in actual patients in real people over seven years. The key takeaway from Cordia Prev is this, in people who already had coronary heart disease following a Mediterranean diet rich in extra virgin olive oil, significantly reduced carotid IMT, plaque height, and plaque burden. And it wasn't just imaging. The Mediterranean diet also translated into fewer cardiovascular events, and about a 25% lower risk of having one. For me though, the most groundbreaking, the biggest learning from Cordia Prev, and also predimed is that a low fat diet, which was strongly recommended in guidelines through the 90s and through the early 2000s. As adhered to by most people in real life, is not as heart healthy as a Mediterranean diet, which is a high quality dietary pattern that encourages the consumption of healthy fats, of healthy carbohydrates rich in fiber, and healthy protein. Low fat diets can be hard healthy, but as we see in these trials, most of the time it tends to reduce diet quality, because people tend to substitute higher fat foods with refined sources of carbohydrates that are low in healthy fats and low in fiber. There's also evidence to suggest that mono unsaturated and polyunsaturated fats are inherently hard healthy, so reducing them too low could actually be problematic. Now, would a Mediterranean diet be healthier than a low fat whole food plant-based diet, where total fat is under 20% of total calories? Well, we don't have the data to answer that. Certainly not from a cardiovascular event or a plaque progression point of view. I do have my own theories here and speculation, and perhaps that's something I'll cover in a future episode. Now, let's jump to the Disco CT trial published in 2021. Disco CT stands for Dietary Intervention to Stop coronary atherosclerosis by Computed to Mography. What makes this study particularly unique is that it used coronary CT angiography paired with the clearly health AI analysis. Unlike the older angiography methods that just measured the artery opening, CT angiography actually lets us see and quantify different types of plaque in the artery wall, calcified, fibrous, non-calcified plaque, etc. Which gives us a much more complete picture of atherosclerosis. The question in this study in Disco CT was if everyone is already on optimal medical therapy, the standard evidence-based drugs for coronary artery disease can an intensive lifestyle program on top of that, slow or even reverse plaque progression, more than medication alone. The trial included 89 adults, average age around 60, about 40% of whom were women. All of them had non-obstructive coronary atherosclerosis, meaning less than 70% narrowing of their arteries. Participants were randomized into one of two groups, the first was the lifestyle intervention group, which included intensive dietary counseling, built around the dash diet, which is a diet that's high in fruits and vegetables, whole grains, low fat dairy, lean protein, and nuts, and it also limits saturated fat, sweets, and processed food. All subjects in this group got individualized meal plans, containing 1600 up to 2600 calories, depending on their needs, and were encouraged to eat five times a day, and to exercise at least three times per week for 30 minutes. Group two was the medical therapy only group, they continued on standard medical therapy and general lifestyle advice from their doctors, but no structured dietitian led program. It's important to note that about two-thirds of participants were on statins, though only 16% were on high intensity doses, and both groups had very similar medication use at baseline and throughout the trial, so the difference really came down to the lifestyle intervention. The follow-up lasted about 67 weeks, so just over a year, and the researchers used CT angiography to measure overall plaque burden, as well as plaque composition. And here's what they found, total plaque burden actually worsened in both groups. It increased by 1.1% in the medical therapy group and 1% in the lifestyle group, and that difference was not significant between groups. But when they looked at non-calcified plaque volume, the softer, more dangerous type of plaque, that's more prone to rupture than I mentioned earlier. This is where things got very interesting. In the lifestyle group, the group where they adopted a dash diet and started exercising, non-calcified plaque volume decreased significantly by about 1.7%. Whereas in the medical therapy group, it also decreased, but only by about 0.7% and this wasn't statistically significant. For calcified and fibrous plaque, there were no meaningful changes between the groups. So what does all of this mean? Make it make sense. The overall plaque burden did not differ between groups over just 1.3 years. But the lifestyle program did seem to help reduce this high-risk, non-calcified plaque, which is exactly the type we most want to shrink or stabilize. And honestly, I was a little surprised that they could see this difference in soft plaque so quickly. Just over a year isn't long in the world of atherosclerosis. Imagine what these results might look like if we followed people for five or ten years. The signal that we're seeing here in just over a year could turn into a much larger effect over the long run. Of course, disco CT, like all the trials we've been speaking about, does have its own limitations. The trial was relatively small with fewer than 100 participants. And the follow-up was short compared to the five to seven-year studies that we've looked at. Plus like many lifestyle trials, the intervention combined diet, exercise and other behavior changes. So we can't say exactly which factor was responsible for the benefit. But the key takeaway is this, even in people who were already on optimal medical therapy, adding an intensive lifestyle program that's centered on the dash diet led to a measurable reduction in non-calcified plaque. That shows us that there's still room for lifestyle on top of medication. The message is simple, even if you're already on the right drugs, including stands. Lifestyle still matters. Diet, exercise and other healthy habits add another layer of protection, and that can be really powerful. At the highest level, these six studies together show us that various lifestyle approaches, including a Mediterranean diet, a vegetarian diet, or broader lifestyle programs, can stabilize atherosclerosis, even modestly reversing plaque in some cases, and most importantly, lower the risk of having a cardiovascular event. Because trials like the stars trial, predium ed and cordia prev, isolated the effect of diet alone without changing other lifestyle factors, we know that nutrition by itself can influence the rate of plaque progression in our arteries. That is something that we can say. So to answer the question from the beginning of this episode, yes, it does appear that diet alone can lead to some degree of plaque regression, or at least to make the artery less narrow. Some would call that a reversal of atherosclerosis. Across all six studies, a consistent dietary shift emerged. Less saturated fat, typically replaced with more mono and polyunsaturated fats, and fewer refined carbohydrates, replaced by fiber rich foods, like whole grains and legumes. These dietary changes are known to improve several key cardiovascular risk factors, including cholesterol levels, inflammation, endothelial function, and blood pressure, which together likely explain at least in part the improvement scene in atherosclerosis. One of the more fascinating findings came from the disco CT study. Remember, this was the only trial that used imaging that was sensitive enough to assess plaque composition, and it showed that diet is not just a lever to slow plaque buildup. It can actually change the type of plaque that we have and make it more stable. Specifically, diets high in fiber and unsaturated fats and low insaturated fat, patterns that lower APOB and reduce inflammation appear to promote plaque stability, making existing plaques less likely to rupture. Before I let you go here, I am going to finish up with my three biggest takeaways from the six randomized controlled trials on nutrition and atherosclerosis. My first big takeaway is that it's never too early to start. The earlier you act, the more years you spend protecting your arteries. Predeam ed showed that even before a first heart attack or a stroke, diet alone reduced cardiovascular events by nearly a third. Prevention isn't something for later. It's something to start now today. My second biggest takeaway is that quality matters more than macro nutrients. For years, we were told that a low fat diet was the key to heart health, but these randomized controlled trials together show that it's not so much about how much fat you eat, more so about what kind of fat you eat. Diet's rich in extra virgin olive oil, nuts and seeds, and low insaturated fat, reduce inflammation and improve blood vessel function. By contrast, low fat diets that swap healthy fats for refined carbohydrates tend to do the opposite. And my third biggest takeaway is to stack your tools. If your doctor recommends a statin or another lipid-loan therapy, don't see this as an alternative to lifestyle. See it as an addition. The best outcomes come from stacking diet, exercise, and medications when needed. That's what we saw in trials like Scrip and Disco CT. Medications and lifestyle didn't just add their benefits together. They multiplied them. That's it. We did it. If you found this episode helpful, please share it with someone who might benefit any friends or family members. And if you haven't already, please hit subscribe. It genuinely helps me bring more evidence-based conversations like this one. And lastly, before I go an important question to leave you with, why did the plot go to therapy? Because it had too many issues with attachment. I couldn't help myself. I'm sorry. Actually, no, I'm not. All right, go on. Get out of here and I'll catch you in the next episode.