This study published in the Journal of the American Heart Association has really lit up social media. This is a timely article because there are lots of people in the whole food plant-based community who are claiming that oil is pretty much the worst thing ever. That seems to be everyone's favorite thing to do, right? Demonize a specific food because that's a really great way of getting clicks and attention. But like most things, it's usually a bit more nuanced than that. So we're gonna talk about that today. So let's dive in here specifically. So what we're gonna look at here is a article in the Journal of American Heart Association, recipe for heart health, a randomized crossover trial on cardio metabolic effects of extra virgin olive oil within a whole food plant-based vegan diet. It's a lot of words. So what we're looking at today though, specifically is the role of olive oil in a specific whole food plant-based. It's another way of saying vegan diet. What does it look like? So let's dive in here and why we're doing this. What's the first thing about that? Why do we care about it? Well, it's well known that there are lots of diets that can improve cardio metabolic risk factors, right? So whether it's Mediterranean diet or whole food plant-based diet or low carb diet, there's lots of things that can be done and lots of diets that you can partake in that improve lots of different markers. And a lot of times they have much more in common than most people think, right? They have generally high quality foods, minimally processed, things like that. And so a poor quality diet is a leading risk factor though for cardio metabolic disease worldwide. And things like I mentioned before, plant-based diets, Mediterranean diets, lots of veggies and vegan diets, they're recommended for reducing the risk of cardiovascular disease. And there are debates though, which people are, you know, in the nuanced nerd world of nutrition saying, "Hey, is it better to have a super low fat or moderate low fat or whatever?" And so there's lots of debate in those circles. I think overall much more academic conversations happening and people are like, "Oh, is it this or this?" Where the vast majority of Americans just need to do like something, you know. Most people are like way over here, like eating Cheetos and Fritos and doing all this stuff. And then we have this people over here, this group of people saying, "Well, is it this amount of fat, oil, not oil?" It's like, man, we just need to get people to eat vegetables and things that don't come out of packages. Like that's really where it is. But nevertheless, here we are. I'm one of those nerds too. So we're talking about it. But that being said, I don't want anyone to freak out or think, you know, this is too hard. But that's what we're looking at here specifically. And vegan diets though, they can vary widely in the composition and quality. And so specifically what they look at are whole unrefined foods, minimally processed, you know, no refined gains, minimally added sugars or oils. And that's what we're looking at. And what they're saying here, and a lot of people on social media are saying that this diet here specifically, they're saying, "Hey, high olive oil, increase your risk factors and raise your cholesterol." That was the big takeaway from the article is that a higher olive oil diet, raise your cholesterol. And so that's the claim we're gonna look after here. And like most things, spoiler alert, it's not really true. It's sensationalized big time. There's some truth to it, but not really. So how did they do this study? Well, it was a prospective crossover trial looking at, once again, high versus low olive oil consumption. And it was prospective open label crossover trial. And a crossover trial means that both groups got the treatment. So what I mean by crossover means, let's say I'm in this study, let's just pretend I'm in this study. I would take a turn on the low olive oil group, that'd be one. And then I would have a washout period where I'd kind of eat my normal diet. And then I would go in the quote unquote, "Higher fat diet" group. So I am crossing over to both sides. I'm doing both things. That's what a crossover diet essentially means. And the people that were in here, they were adults with greater than 5% cardiovascular disease risk. And they either had a high olive oil diet, which were four tablespoons a day, or low, which was less than one teaspoon a day, which is not a lot. And this was four weeks. They followed by, they had a one week washout and then four weeks again. So I did low olive oil for four weeks, washout, then another four weeks. And that's what I looked at. And they said greater than 5% risks. I mean, these are people who are at some risk of having cardiovascular disease based on probably the Framingham calculator. So that's where we get those numbers from. And these participants ranged anywhere from 18 to 79. And they were once again borderline high risk for cardiovascular disease. And they got these through medical clinics is what we're looking at. And specifically they did exclude people if they were there for secondary prevention. Secondary means that they had an event, right? So secondary prevention means we want to stop the second thing from happening. So they've already had that. We want primary prevention. So these patients are primary prevention, meaning, hey, they have not had a cardiovascular event yet. That's specifically what we're looking at here. And the dietary intervention, what happened here was all the olive oil was provided. So people don't have to go out. So it's the same olive oil, which is nice. And they were instructed to consume it raw. I mean, hey, I'm not saying that they're taking shots of olive oil, but they're saying, hey, putting it on salad, stuff like that, not necessarily cooking with it. So that's what they mean by raw. And once again, they kind of emphasize absence from any animal products or heavily processed or refined food items and really emphasize whole fruits, veggies, legumes, whole grains, nuts, and seeds. They did provide a B12 supplement as well, as that's not found anywhere in a vegan diet. But they didn't tell them, hey, this is how much you should eat. So they gave no specific quantity of food to eat or macros or calories, anything like that. They said, okay, go to town, eat that. So that's one big caveat we have to consider. And they were advised to eat according to their hunger cues. And what did they look at? Well, the primary outcome, so the main outcome they're looking at here was change in LDL cholesterol from baseline between diet periods. And so LDL is the big marker here. They did get a bunch of alcohol, but like the primary was there. And secondary here, we wanna talk about those as well. We also looked at lots of things, like we looked at lipids, different things, A-Pylo protein, L-P-A-A, glucose, fructoseamine, IL-6, C-R-P, all these things. And that's what they looked at. And so those are the big outcomes. And they did use food frequency questionnaires to kind of track what they ate. So which, those are controversial, meaning people had to recall what they ate. They weren't writing down in real time necessarily what they ate. So they say, okay, yesterday I ate this, today I ate that, or at the end of the day, that's a really challenging thing. I think that's one thing in nutritional epidemiology that can be very challenging is food frequency questionnaires. People will say, oh, like they're validated. And they are, but I mean, I barely remember what I ate this morning, let alone yesterday or the day before. And so it's not that accurate. Also quantity-wise, it's hard, but that's what they used and that's the design. That's totally fine. But they did have it. They also measured a bunch of different stuff. As I mentioned, they took blood and urine samples, looking at baseline. They also measured body weight, blood pressure, heart rate, waist and hip circumference, so all of those things. And what did they find? Well, overall, both diets resulted in decreased LDL levels compared to baseline, but there were no significant differences between groups. So that's like the takeaway headline. There was no significant difference between groups. Then what the heck, where are the headlines coming from? Saying that high olive oil increases your cholesterol. Well, that's where the nuance of this paper comes in and we'll kind of dive in here a little bit. So there were 40 adults, mostly females, 30 versus 10, age average about 64, and both diets reduced and decreased LDL-C when compared to baseline, but once again, no significant difference between groups. So what they looked at there is, hey, from your baseline of where you started, if you were in high olive oil or low olive oil, both of those groups got improvement and saw decrease in LDL. So that's like a big takeaway and there's no significant difference. What happened though is they look at diet sequence. So what they mean here is that diet sequence was, if you were in the high olive oil group first, then the washout, then low, so that's one sequence going high to low, and then there's low to high. And those are the sequences they said, "Hey, was there a difference in these sequences?" And that's kind of where the social media headlines came from here. And what they found was there was clinically larger LDL-C reductions after the low olive oil diet versus the high one. And simply going low to high led to increased glucose, total cholesterol, and HDL-C. So this is where the headlines come from, right? So they're saying, "Oh my gosh, when you go from the low olive oil to high olive oil, you're increasing glucose and total cholesterol, but then also HDL, which is beneficial." But either way, what they're saying, that's the takeaway people are saying. They're saying, "Oh my gosh, increase HDL. Don't stay away from olive oil, it's bad." What they didn't mention was like, it's still significantly lower than the baseline. And so it wasn't like it got all the way back up to the baseline saying, "Hey, they were here, and you have olive oil, and you went here." It's like, no, both of them had significant reductions and pretty much the same, right? So it didn't matter which group, they're pretty much the same overall, but there was some signal in there saying that, "Hey, if you went specifically to lower olive oil, you had a bigger reduction." But once again, there wasn't any statistical significant difference there, but that's where people are saying, "Hey, when you were at that low olive oil, then you crossed over to the high olive oil, that's when you saw the quote unquote raise in your cholesterol, and you raised it from that lower level but still was an overall improvement from where they were at baseline." And that's the big thing I really wanna push, and say, take home, this is what's happening there. So they also looked at lots of other things. Both of them significantly decreased total cholesterol, APO-B, improved HDL, improved glucose, and CRP, which is inflammatory marker. So pretty much everything improved from baseline. Body weight decreased significantly after both diets, but more with the lower olive oil, and that one actually was statistically significant. And fat intake, what they did mention was that about 48% of the high in the high group, but 48% of the calories were from fat, where in the low is only 32%. So not like they were sitting overall diet of 10% fat, so they're still sitting 30, 40, but 40 in the higher one and 30, which makes sense if you're eating more, that's gonna happen, but it was different there. And then physical activity, there were no significant differences. And what's the big takeaway here is that headlines on social media are not 100% accurate. Probably shocking news of the day, right? What you read, and that's what's really frustrating. What's really frustrating is that you read this headline, or you see someone talk about it, and then you hear contradictory things to that. And you have people like me saying like, well, actually it's not the whole case. And you're just like, why can't it be reported like that? I don't want to tell you, it's not cool. This doesn't get clicks because it's not as click-baity. We try to get the click that's important so you can learn the information, but headlines aren't always the full truth, that's for sure. Both of these diets, the high and low olive oil diets reduced LDL, but they did say the lower olive oil group did yield more pronounced decrease, but it wasn't statistically significant. So that's like kind of where people were saying, hey, it's actually worse. And the thing is the reductions occurred despite high fat intake, even during that high olive oil phase, so at 48% fat. And then the biggest thing was adding that extra virgin olive oil after a low intake period may impede lipid reductions. By impede lipid reduction, you might see a little bit bump up back in some of your cholesterol numbers. That's like the big scary headline from this, but overall, as I'm hopefully showing you here, it's not that big of a deal or really concerning at all. And why did this happen? How? They're not quite sure. They thought that maybe the low fat diet may have led to greater fiber intake due to a higher proportion of whole plant-based fats contributing to the LDL C reductions, maybe more consumption of phytochemicals in plant fats, which may play a role, and then slightly higher saturated fat intake in the high olive oil group may have contributed to those LDL differences as well, as we know that consumption of saturated fat can sometimes drive up LDL. And so those are all potential mechanisms for why it happened. Do we know definitively? No, we'll never know. But that's kind of a couple of things they thought about. And as I mentioned, those sequences did seem to have some effects. The carryover effects were observed despite the washout period, meaning, hey, we had that washout period, and we saw these differences between high and low and kind of a little bit of different here and there. So they're saying maybe the washout period wasn't long enough to kind of like get us back to baseline. So that may be playing a role, that maybe the washout period was too quick, and that may be playing a factor as well. Who knows? Not necessarily sure. But overall, I think the big clinical takeaway here is that either these diets is fine, but a low one. If you're trying to get all the benefits, then maybe a little lower fat diet will be more beneficial. And I think that's pretty well known and pretty standardized.
