Science Vs - Seed Oils: Is Your Canola Oil Killing You?

Episode Date: October 26, 2023

We’ve been told that foods like butter and bacon are bad for us — because they're packed with saturated fats. And top dogs in nutrition say that a better option is vegetable oil, like canola oil. But there’s a trend popping off claiming that these top dogs are barking up the wrong tree. They say that butter is better and that those vegetable oils, aka “seed oils,” are incredibly dangerous. So — who’s right? Is canola oil really killing us? Or is butter the bad boy? To find out, we speak to author and physician Dr Cate Shanahan, professor of nutrition science Jason Wu, professor of endocrinology David Schade, and Dr David Iggman. Find our transcript here: https://bit.ly/ScienceVsSeedOils  A new Season of Heavyweight is out now! Find them here: https://gimletmedia.com/shows/heavyweight  In this episode, we cover: (00:00) Seed oils are the devil (05:35) Is saturated fat killing you? (12:25) Does cholesterol cause heart attacks?  (22:02) Do seed oils cause inflammation? (28:00) Are seed oils killing you? This episode was produced by Wendy Zukerman, with help from Joel Werner, Rose Rimler, Nick DelRose and Michelle Dang. We’re edited by Blythe Terrell. Fact checking by Carmen Drahl. Mix and sound design by Bumi Hidaka. Music written by Bobby Lord, Emma Munger, Peter Leonard, and Bumi Hidaka. Thanks to all the researchers we spoke to including Dr Lorena Pacheco, Dr Qi Sun, Dr Tetsumori Yamashima, Dr Idrees Mughal, Professor Rashika Ahmed, Dr Hatem Tallima, Dr Heidi Silver, Professor Ronald Krauss, Dr Yutang Wang, Dr David Sullivan, Professor Peter Clifton, Dr Lee Hooper and others. And a big thank you to Morgen Rockel, the Zukerman Family and Joseph Lavelle Wilson. Science Vs is a Spotify Studios Original. Listen for free on Spotify or wherever you get your podcasts. Follow us and tap the bell for episode notifications. Learn more about your ad choices. Visit podcastchoices.com/adchoices

Hi, I'm Wendy Zuckerman and you're listening to Science Versus. And today on the show, we are pitting facts against fats. For years, the top dogs in nutrition have been howling about how foods like butter and bacon are bad for us because they are packed with saturated fats. And instead, they say, we should be eating vegetable oils. These oils are filled with a different combination of fats that experts have told us are good for us. But there's a trend that's popping off right now

that says that these top dogs are barking up the wrong tree. And in fact, butter is healthy and those vegetable oils, which are probably sitting on your kitchen countertop right now, are actually incredibly dangerous and might even be killing you. Medical science is messed up when it comes to nutrition. This is Dr. Kate Shanahan. She's a family physician who's been raging against the nutrition science machine. It's just so wrong. It's morally wrong.

It's ethically wrong. It's shocking. And I just, after 20 years, I still haven't gotten over it. Kate has a big problem with vegetable oils that are extracted from seeds. The so-called seed oils. What exactly are the seed oils? The problematic seed oils are a collection of eight highly refined, industrially processed vegetable oils. Specifically, soy, safflower, sunflower, corn, cottonseed, canola,

and rice bran and grapeseed oil. Kate calls these oils the hateful eight. You might have noticed your olive oil is still fine, but canola oil and soybean oil, they are in the bad books. It's the vegetable oils that are often yellow when come in those giant plastic bottles, and you'll find them in lots of different foods. So they are in salad dressing,

your canned tuna, preserved veggies are in, even olives these days, they're often in soy oil, frozen dinners, gator tots, microwave popcorn, granola, you know, supposedly healthy granola. In a book that Kate wrote on this topic, which really helped kick off this new seed oils trend, she wrote that, quote, avoiding vegetable oils is the most

important action you can take to improve your health, end quote. Because according to Kate, eating a lot of seed oils produces a ton of inflammation in your body, increasing your risk of an array of diseases, from heart disease to cancer. If I were to list all of the diseases you can get by eating seed oils, this podcast would be going on for until tomorrow. There's too many. It's every single one they contribute to. And so instead of eating these seed oils, Kate wants you to be chowing down on something else. Saturated fat. The very fats that doctors will tell you to avoid. We're talking about, you know, fatty cuts of meat like steak and, you know, pork and bacon and dairy fat like butter and cheese and cream and eggs.

This is really the list of like the demonized list. This is really like a no, no, no, no, no, no, no, no list. I know. And, you know, dietitians listening to this are probably thinking she's a loon. But Kate went on this diet herself. Seed oils out, saturated fat in. And she said she felt great. She even started putting her patients on this diet.

And she told me that she's seen some miraculous things. People who've done it feel better and they feel better than ever. They feel younger in their 60s than I did in my 30s. They say that I had diabetes and I got off my diabetes medications in a weekend. I had heart failure. I no longer have heart failure. My kidneys were failing. They're better now. And it's not just Kate who's saying this kind of thing. This idea has blown up. People all over socials and podcasts

are swearing by this diet. And they're saying that you need to stop eating seed oils. Seed oils are some of the worst f***ing things your body can consume. These oils are inflammatory. They've been linked to stop eating seed oils. Seed oils are some of the worst f***ing things your body can consume. These oils are inflammatory. They've been linked to heart disease, cancer. They are poisons, plain and simple. Seed oils are of the devil.

They are the cause of every problem in the world. Wow. Almost. So today on the show, we are finding out what is going on here. Is your canola oil really killing you? And is butter now healthy? It's the ultimate clash of the titans. In one corner, seed oils. In the other, your bacony, buttery, saturated fat. Who will win? And I gotta tell you, chewing the fat on this one, I haven't worked on an episode of Science Versus that has upended so many of my views about food.

When it comes to this diet, there's a lot of... Seed oils are of the devil. But then there's science. Science Versus Seed Oils is coming up just after the break. What does the AI revolution mean for jobs, for getting things done? Who are the people creating this technology and what do they think? I'm Rana El-Khelyoubi, an AI scientist, entrepreneur, investor, and now host of the new podcast, Pioneers of AI. Think of it as your guide for all things AI, with the most human issues at the center. Join me every Wednesday for Pioneers of AI. And don't forget to subscribe wherever you tune in.

It's season three of The Joy of Why, and I still have a lot of questions. Like, what is this thing we call time? Why does altruism exist? And where is Jan 11? I'm here, astrophysicist and co-host, ready for anything. That's right. I'm bringing in the A-team. So brace yourselves.

Get ready to learn. I'm Jan 11. I'm Steve Strogatz. And this is... Quantum Magazine's podcast, The Joy of Why. New episodes drop every other Thursday, starting February 1st. Welcome back. Today, it's seed oils versus saturated fat.

Should you ditch your canola oil, like Kate Shanahan says, and fill your belly with butter and bacon instead? To get to the bottom of this, let's leave Kate for now and go on an adventure to simpler times, where the shoulder pads are sky high and the messages that we got about saturated fat were crystal clear. Back in the 80s and 90s, we were told that eating foods high in saturated fats, so think meats, butter, cream, was one of the worst things you could do for your health. Why? Because these foods raise your cholesterol and increase your risk of heart disease. If you eat too much of this, then over time fatty deposits could build up in your arteries and this increases your risk of heart disease.

Here's this grim ad from the UK in the 90s. You can see a glass jug filled with fat that someone is slowly pouring down their kitchen sink. The saturated fat can clog this pipe. Imagine what it's doing to yours. In the US, this was the vibe. Ken doll-looking fellas were mansplaining dietary advice to their ladies. Oh, and in Australia? But song or no song, the message was clear. Saturated fat is bad. So is this true? To find out, we need to meet a new guest. So please introduce yourself. Yeah, sure. My name is Jason Wu. I'm a

professor and head of the nutrition science team at the George Institute for Global Health, based in Sydney, Australia. I'm on the land of the Gadigal people of the Euronation. I've always just known that saturated fats are bad. When did you first get the message that saturated fats are bad for us? Certainly, it was from a pretty young age as well. You know, I was born in the 80s and my family, my parents, you know, just about every person when they think about nutrition around, oh, if I want to be healthy, I just got to stay away from it. So it's a message that has been around for a long time. Yeah, that message partly dates back to some controversial research from the 1950s,

suggesting that some countries where people eat a lot of saturated fat, like the US, Canada and Australia, also have higher rates of heart disease compared to countries where people don't eat that much of it. And since then, we've had a whole lot more evidence, which I'm happy to go into, that sort of suggested that the story is not as simple as it would have seemed. So let's get into this evidence. Saturated fat is a type of fat that's generally solid at room temperature. So think of chunks of lard, coconut oil, palm oil, and of course, butter.

Butter is sort of what's traditionally held up as the poster child of what to avoid, right? It is a big chunk of saturated fat, right? Right, right, of animal-based, right, right, saturated fat. If you imagine a stick of butter, half of that is literally saturated fat. And several years ago, Jason and his colleagues wanted to see if butter was really that bad for us. So they scoured through the literature, grabbing all these studies that had looked at whether people who ate a lot of butter had higher rates of things like heart disease, stroke, diabetes, and even premature death. We don't just cherry pick one study, two studies. We pull these kinds of studies together

and say, if you look at them all together, what does it tell us? They found nine studies that included more than 600,000 people who'd been followed for many years, and every now and then quizzed about what kinds of foods they were eating and particularly how much butter they were popping in their pie hole. By the end of the study, nearly 10,000 people had heart disease and more than 28,000 had died. So, did the butter boys fare worse?

Well, let's start with the worst possible thing here. Premature death. People who reported eating more butter had an ever so slightly elevated risk of total mortality. Okay. For every serve, so about 14 grams of butter per day, it's about a 1% barely statistically significant elevated risk of premature death. Got that?

Eating a bit of butter every day increased your risk of dying prematurely by 1%. So it's clearly not arsenic here. And then when we zoom in on heart disease, what was the link between getting a heart attack or stroke and eating butter? Zero. Absolutely no relationship between eating more butter and heart disease risk. Oh, wow. With diabetes, eating a little butter actually lowered your risk of getting it by around 4%, which I couldn't believe. Lower risk of type 2 diabetes. You heard that correctly. So it's a very, very small amount. Just to give you something in comparison, in similar kinds of analysis, looking at things like sugary drinks, Coca-Cola, Pepsi, every one serve per day of a can of Coke

is related to nearly 20% higher risk of type 2 diabetes. So just to give you a sense of... Just to say, yeah, yeah. And this was like in the 1%, 2% in either direction. Right, yeah, yeah. In 2016, Jason and his team published this study and gave it the title, Is Butter Back? And some scientists couldn't believe it.

When it first came out, it was very controversial. A lot of people sort of took us to task and said, oh, look, you know, this is, I mean, butter is clearly bad for you. And we said, well, we've just shown you the evidence. And if you've got other evidence you would like to present to us and say how terrible it is, you know, like on the realm of sugary drinks, I'm all for it. Please show us that data. Please show us that evidence. And none were really particularly forthcoming. So that is butter. Now, when you zoom out to all kinds of foods that are rich in saturated fat,

so not just butter, but also stuff like cream, lard, bacon, beef, pork, sausages, the research is a little more mixed. Like one big review did find that overall, shoving less saturated fat down your gob could cut your risk of heart disease by a bit. But still, the message coming out of science right now is that saturated fat is not the big killer

that the 80s led us to believe. Turns out it was the shoulder pads all along. But this did make me wonder, what does this mean for that whole story that we've been told about why saturated fat is bad? Like, you know, that foods like butter and bacon clog our arteries with dangerous cholesterol and then, bam, heart attack. Like, is that whole story a lie? Because some headlines seem to be suggesting, yeah.

High cholesterol may not mean heart disease in your future after all. Most Americans believe heart attacks happen when cholesterol clogs your arteries. In reality, cholesterol is actually not the main culprit. Some are even saying that cholesterol is healthy for us. So what is going on here? To find out, I called up David Shade, a professor of endocrinology at the University of New Mexico Health Sciences Center on the other side of the globe. Are you still in Australia?

I am still in Australia. Wow, we're doing this across the world. This is amazing. It's good, right? I've never done it before. So this is exciting to me. And it was exciting for me to chat to David because I wanted to know, is it possible that cholesterol is good for us?

And David was like, well, duh, yeah. Cholesterol is super important. So we're all made up of billions of cells, right? Skin cells, heart cells, muscle cells. And something has to keep those cells together. Otherwise, we'd all be a pile of jello, right? But we're not a pile of jello. The reason we are not a pile of jello is partly thanks to cholesterol, which is this waxy, yellowish fat that hangs out in the lining of our cells, giving them structure. We also use

cholesterol to make a bunch of hormones like cortisol and testosterone. So cholesterol is absolutely critical. And so then tell me, how did cholesterol get such a bad name? Okay, so a little bit is great, but too much is bad. So David tells me, here's the deal. To travel around your body doing all of its important things, cholesterol travels in these little balls of fat via the highway that is your blood. But when you have too much of this particular kind of cholesterol called LDL cholesterol swimming around in your blood vessels,

some of it can get trapped in these teeny tiny holes in the lining of your arteries. And this becomes an issue. Now, we used to think that cholesterol literally clogged up your arteries. But now we know that's not entirely true. It's actually that your body tries to get rid of that nasty cholesterol with the help of these immune cells called macrophages. Okay, those cells are really scavenger cells. They take up any bits of old cells around dead things. They're scavengers.

And if they see little droplets of cholesterol, they take it up. They're like little Pac-Man, like Pac-Man. Exactly, exactly. And they eat cholesterol. But they eat so much that they die, basically. And what can happen is that if you have more and more bad cholesterol in your blood, you end up with this big, gross pylon. That's exactly what happens.

They pile up. You can see these yellow streaks in the arteries. And those are macrophages just practically dead, just full of cholesterol. That's bad news. Eventually that big globby mess of Pac-Man, cholesterol and other stuff builds up and up and up forming what we call a plaque and that can rupture or explode into your blood vessels, causing a heart attack. So having too much LDL cholesterol or bad cholesterol does up your risk of getting heart disease.

And science has shown this again and again and again. And the thing is, eating a diet that's high in saturated fat, the kind of diet that Dr. Kate Shanahan, who we met at the start of the show, is promoting. On average, that kind of diet, it actually increases the amount of LDL cholesterol swimming in your blood. And in fact, on this diet, Kate's bad cholesterol went up. My cholesterol levels have gone through the roof

since I started this. Yeah, I have a patient like that. And David has seen this as well. So according to the CDC, a healthy LDL level is roughly 100. And we're talking about their LDL cholesterol went from 110 to 430. Whoa! Yeah, she went on that kind of diet. Really?

And it zoomed way up to 430. Yeah, that's terrible. The big question is, if eating saturated fat ups your bad cholesterol and bad cholesterol ups your risk of heart disease, then why aren't we finding that butter and even saturated fat more generally are that bad? Well, here's how David sees it. You know, on the field of heart disease, there's a bunch of players. There's smoking as a player, hypertension as a player, and then there's saturated fat. Well, it's about a 1% player out of the whole 100% field. It's not an important player. And there's a couple of reasons why saturated fat isn't an important player here.

One is that what makes up your bad LDL cholesterol isn't just how much saturated fat you eat. In fact, a huge chunk of your LDL cholesterol is actually produced by your own body. And some people, thanks to their genes, just naturally have very high LDL levels. And then there is this super interesting idea that I actually had no idea about until I started researching for this episode. So do you remember how this bad cholesterol gets into the little holes in the lining of your arteries? And that kicks off the process with the Pac-Man and the big globby mess that can eventually lead to a heart attack. Well, what we are learning is that there are different kinds of bad cholesterol that come in different sizes. As with everything else, there are different sizes of people,

there are different sizes of dogs, there are different sizes of cholesterol particles that circulate around in you. Okay. Now it turns out since the cholesterol has to go through these pores, the little ones go through much easier than the big ones. So the little ones are much more dangerous than the big ones. You can think about it like this. The smaller the dog, the rattier it tends to be. The smaller the cholesterol, the more dangerous it tends to be. And research is suggesting that the kind of cholesterol that saturated fat ups in your blood is kind of like a pug-sized cholesterol. So it's not great, but it's not some shitty chihuahua. And then finally, there's something else going on here. When you eat foods with saturated fat, you're not just eating fat. Like if you think of a stick of butter, there's other stuff in it, like omega-3

fatty acids, calcium, and vitamin D, all of which might play a role in reducing your risk of heart disease. So maybe when you eat some of these saturated fatty foods, you might up your bad cholesterol, which increases your risk of heart disease, but then you might end up with some more nutrients, which lowers your risk of heart disease. So at the end of the day, when it comes to butter, here's how Jason sees it. And I think this is a really important point. And no point in time do we say that, therefore, go and knock yourself out. Eat as much butter as you like, right? Because that clearly also isn't what we found.

We basically found a somewhat neutral to marginal effect of butter. Neutral to marginal effect. Perhaps a Jurassic Park analogy might help us here. Saturated fat is no T-Rex. It's not a big killer. But it's not Laura Dern either. It's more of a Jeff Goldblum, you know, like a bit creepy, but also kind of fun. And you know, if you personally have a high risk of heart disease,

then cutting back on saturated fats is something that you can do to reduce your risk. But bottom line, I think Dr. Kate Shanahan, who we met at the start of the show, she has a point when she says that these foods aren't as bad as we've been told they are. But to Kate, the real velociraptor in the kitchen are seed oils. She says that it's these oils that are causing an array of diseases inside your body. And with the help of thousands of muffins and a whole lot of butt fat, we're going to find out if she's right after the break. Welcome back.

Today on the show, we're looking into this new diet that wants you to throw out your seed oils. So think canola oil, corn oil, that giant bottle of yellow stuff in your kitchen. Get rid of it, people are saying. Why? Because they are toxic. And if that's true, it's troubling because in the US, consumption of seed oils has more than doubled since the 1960s. Dr. Kate Shanahan, who's the queen of this new diet, says that as we've been eating more and more seed oils, our rates of

certain diseases have gone up and up. There's this graph that she uses on her website and book, and it's flown around the internet, that shows seed oil consumption skyrocketing alongside various diseases, like obesity and cancer. We have the entire population of the United States consuming more seed oils than ever, every year. How can you explain that if seed oils are healthy? How do you explain that? Everyone's asking us to ignore this. It's like the man behind the

curtain on The Wizard of Oz. Don't pay any attention to what you see with your own eyes. Now, this is, of course, just a correlation. And, you know, one big reason why cancer rates are going up is because our population has been getting older and older. And Kate told me that she knows correlation doesn't equal causation. But she's also pretty convinced that seed oils are mucking up our bodies. And so what diseases do you think eating seed oils are linked to? Can you list them off for us? So just to list some diseases that are common, I see a lot. Actually, let's start with the good news.

Let's give some little good news here. Things that go away really quickly when you stop eating seed oils are skin conditions like acne, inflammatory skin conditions like acne and eczema and recurring hives, inflammatory digestive systems get a lot better. And even irritable bowel, even celiac disease, I think brain cancer, dementia and Parkinson's, heart attacks, they cause heart attacks. So there's nothing that they don't cause. And that means there's nothing that won't get better, at least a little bit and maybe a whole lot when you stop eating seed oils.

So in Kate's mind, this long list of diseases are connected by one thing, inflammation. And based on quite a lot of theory, Kate reckons that by looking at the biochemistry, you know, examining what makes up these seed oils at a molecular level, she thinks that when we burn these seed oils for fuel in our body, it releases free radicals that she says are bad for us. And can release very dangerous particles

into our bodies after we've eaten these things in large amounts. And this, she says, can lead to inflammation. Now, when we asked Kate for her best evidence that seed oils are linked to all those different diseases, a bunch of the papers that she sent us weren't actually about seed oils, but studies connecting oxidative stress,

inflammation and certain illnesses. But if you look in the literature, there have been other theories about whether the fats in these seed oils might cause inflammation. And all over the internet, people are saying that the way that we refine and make these oils puts a bunch of toxins in them that then are dangerous when we eat them. So what we've got is a lot of theory, but now it's time to put it to the test. So you meet David Igman. He's a doctor and researcher at Uppsala University in Sweden, and he has gone to heaven and earth to find out what is up with these fats. Or at least, his team did a lot of baking. We made a lot of muffins, like thousands and thousands of muffins.

But we changed the flavor. Like every week, we had some chocolate, some vanilla, some cinnamon. David and his team baked all of these muffins because he's done a series of studies to find out if you feed people muffins that are packed with either seed oils or saturated fat, what happens? Does inflammation in their body go up or not? So, for example, in one study, he got around 60 people to eat muffins,

some which were made with palm oil, which is a saturated fat, and others were made with sunflower oil, which is a big no-no, according to Kate. So they were like very similar in all aspects, except just what kind of fat we put into them. So people ate these muffins for eight weeks and throughout the experiment, David and his team would then test a bunch of things in their body, including markers of inflammation. Now, if seed oils are indeed bad for us and cause inflammation, then you'd expect that the sunflower oil group would see a bump in their inflammatory markers, right? In your study, what did you find? Did the sunflower oil eating group have more oxidative stress?

No, we measured no increases in inflammation in these markers. And in fact, a big review paper on this topic said that there was, quote, virtually no evidence that adding seed oils to your diet bumps up your inflammatory markers. I talked to Kate about the muffin study. So there's a lot there to unpack. So for one thing, it was an eight-week study. That's not long enough. It takes years before the body composition will change. And secondly, we're not talking about real endpoints

when we're talking about inflammatory markers. Inflammatory markers are blood tests. We don't treat blood tests in medicine. We treat human beings who have real physical feelings. And this brings us to a completely different study that David was a part of. I asked him about it. So what did you do? You took samples of butt fat from these elderly men? Yeah, it was buttock. So in this study, David's team analyzed these fat samples, which had been taken from the

buttocks of more than 800 older Swedish men and then stored for around 15 years. Were you excited when you found out there were these samples in the fridge? We just found this fridge lying around with all these buttock fat samples. And that's not quite how it happened. But yeah, it's a cool study. I mean, it's very impressive that we have all this data. And to understand what David is doing with all of this data, you need to know that seed oils have a bunch of these particular kind of fats in them called polyunsaturated fats. So on a very basic level, you can think about it like this,

butter and bacon equals saturated fat, seed oils equal polyunsaturated fat. Although in reality, life is always more confusing. But basically, whichever fat you're eating more of, if you don't burn it right away as energy, it'll get stored in your body as that kind of fat. And this means that David and his team could look at the makeup of the butt fat in all of their samples and say, well, if you ate a tonne of seed oils 15 years ago, are you now more likely to have something like heart disease

or to die prematurely? Which, if Kate's right, should be crystal clear in their data, right? But it wasn't. In fact, having tons of those fats that come in seed oils... Was connected to lower risk of dying. Oh, so people lived longer. Yeah, if you have more of this in your buttock fat, and if you're a 71-year-old man in Sweden, then you lived longer.

Now, it wasn't by much, and one big review paper found that it probably doesn't make too much of a difference to your lifespan if you eat seed oils or not. But bottom line, they're not finding that seed oils are dangerous here. David concluded that having more of these seed oil fats... In your buttock fat does not seem to be harmful in any way. It may be the opposite. I talked to Kate about this study. Oh, okay. Well, that doesn't make any sense.

When you say doesn't make any sense, what do you mean? That's not what I would predict. And you're right. That does contradict my theory. It is the opposite of the theory, right? That's the opposite of the seed oil theory. That's just suggesting that. Yeah.

Yeah, correct. But it sounds like the opposite. But if you drill down into the details of these studies, which I have done, I usually find that they're missing something very, very important, which makes them misinterpret the finding. Kate took a close look at David's paper, and in an email afterwards, she sent me a few criticisms. One was that she said his study actually did find a link between one of the fats in seed oils and death, but once he adjusted for other risk factors, that link disappeared. I sent these criticisms to David and he wrote back to me saying, among other things, well, you need to adjust for risk factors. These are things like smoking and high blood pressure,

and these things can affect your likelihood of getting heart disease or dying. So if you don't control for this stuff, you can come up with the wrong conclusion and say, blame these fats for something that smoking is doing. And zooming out, there are other kinds of studies that don't use fridges full of buttock fat. And God help me, I'll say buttock as many times as I like. And in these studies, you can find a couple that suggest seed oils up your risk of heart disease.

But the vast majority of the research here doesn't. And in fact, one review looking at almost 50 randomized control trials involving more than 24,000 people found that on average, these oils are probably good for your heart. And that generally speaking, swapping out saturated fat for seed oils, you know, completely contrary to Kate's advice, is actually the healthier thing to do. Here's how Jason sees it, you know, our butter researcher. Replacement of saturated fat with

the polyunsaturated fat does reduce the risk of cardiovascular disease. The exact opposite of what this trend is suggesting. Yeah. So the evidence are pretty consistent. Really? So eating these even like highly refined chemical, as chemically canola as you can get, eating those instead of saturated fat, we're actually seeing better health outcomes. Absolutely. I asked Kate about the science on this. I have looked at these studies and I have found a flaw in all of them. After the first, I don't know, 300 studies, I kind of lost interest in, you know, what is the latest way that they're misinterpreting it, you know. as strong as perhaps you'd like it to be.

You would expect all these studies, even with their flaws, would find that people who have seed oils that have polyunsaturated fats in their blood are doing worse, like even despite the flaws in the studies, right? You would expect. I think you do find that. When I look, I do find that. Right.

I mean, oh, interesting, Because the researchers who did the studies are telling me, like the ones who did, the ones who were getting the fat samples and making the muffins and crunching the numbers, they're telling me they still think polyunsaturated fats and these oils are the healthier ones. That's when they look at the data. That's what they say. It's too large of a leap to make all in one study, right? You can't... But even when they look at the picture, they look at all these different,

the muffin, the fat samples, the blood samples. There's so many others. Even just one study did not convince me, right? It took me many, many, many studies. And it took me knowing biochemistry to become convinced. So a researcher who's doing one study on seed oils in many other studies that they've done, it's a small part of their brain devoted to it. Really what's needed for any paradigm shift is a wholesale restructuring of the way we approach a problem, right? I mean, paradigm shifts are difficult. Going back and forth with Kate on this,

I think it's just that she trusts the few studies out there showing that seed oils are harmful and doesn't trust the many, many studies that show that these oils are fine for you and possibly even healthier. I would talk to my patients and ask them, if somebody came out of the hospital, what did you eat before you went into the hospital? Fish. What'd you fry it in? Canola oil. You know, time and time again, I heard things like that. James Gandolfini, what was his last meal? Do you know? I'm not familiar. He had shrimp deep fried, double serving of it, dipped in mayonnaise, which is made out of seed oils. He had like two portions of that. That's like the worst form of seed oil. He had a heart attack that night and died. Right, and you think that's what killed him?

No, it was a lifetime of seed oils and that was the fatal blow, right? So that's where Kate stands. But there is one final point to make here. Even though on the average, the research tells us that the fats in seed oils are healthier, they're not so healthy that if you're eating a diet full of junk food that happens to have seed oils in it, like chips and tater tots and fast food, that that diet will be good for you.

So, you know, if you go on this new seed oil diet and you bin your seed oils and end up eating a bunch more fruit and veggies and home-cooked meals, you could end up on top. But it probably wasn't avoiding the seed oils that did it. They're more like an innocent bystander here. And so when it comes to this idea that seed oils are the devil and saturated fat is our savior, well, perhaps let's give David Shade, our cholesterol researcher, the final word here. You know, every year there are crazy diets that people put out

without any scientific justification. And that's one of them. It's all crapola. Crapola is how you say it? Crapola. Crapola. Yeah, that's what it is. That's a technical term. That's Science Versus. Hey, Wendy. Hey, Joanna, supervising producer at Science Versus. Are you excited that Seed Oils is now, we finished the episode. That's it, the episode's over. That's right.

Congratulations to the audience. So how many citations were there in the episode today? There were 102 citations, yes. And how can people find these citations? I'm just like looking at them now and my head is spinning, even though I'm the one that put the vast majority of them in there. If people want to see these citations and read more about anything that we talked about today, then head to our show notes and click on the link to the transcript and you'll see like all the citations

to basically every word that came out of my mouth today. And we have a podcast recommendation for you. It is called Heavyweight. It's not a new podcast, but they have a new season out and this podcast is phenomenal, right? Heavyweight's like, I don't know, I feel like it's the podcast that podcasters rave about. Like, people who make podcasts notoriously don't have time to listen as much as they want to and, you know, we're too busy kind of making the thing to listen to the thing. But Heavyweight is the one show that everyone I know

who works in audio never misses an episode of. It's an absolute classic. Yeah, yeah. So go check it out, Heavyweight. It's available on all of your podcast catches just like we are. So, yeah, so go enjoy it. New season, it's going to make you laugh and cry and do both at the same time.

All right. Thanks, Joel. Thanks, Wendy. Bye. Bye. This episode was produced by me, Wendy Zuckerman, with help from Joel Werner, Rose Rimler, Nick Delrose, and Michelle Dang.

We're edited by Blythe Terrell. Fact-checking by Carmen Dral. Mix and sound design by Bumi Hidaka. Music written by Bobby Lord, Emma Munger, Peter Leonard, and Bumi Hidaka. Thank you to all of the researchers that I spoke to. I really went back and forth with a bunch of researchers and I just so much appreciate your time and explaining the science to me. So thank you to everyone I spoke to, including Dr. Lorena Pacheco,

Dr. Chi San, Dr. Tetsumori Yamashima, Dr. Idris Mughal, Professor Rashika Ahmed, Dr. Atem Talima, Dr. Tetsumori Yamashima, Dr. Idris Mughal, Professor Rashika Ahmed, Dr. Atem Talima, Dr. Heidi Silva, Professor Ronald Krauss, Dr. Yutang Wang, Dr. David Sullivan, Professor Peter Clifton,

Dr. Lee Hooper, and others. A big thank you to Morgan Rockall, Jen Mortimer, who put me on this whole seed oils adventure. Thank you, Jen. The Zuckerman family and Joseph Lavelle Wilson. Science Versus is a Spotify Studios original.

You can listen to us for free on Spotify or wherever you get your podcasts. You can find us everywhere. If you are listening on Spotify, follow us and tap the bell icon for episode notifications. And if you like the show, give us a five-star review. Come on, do it. And plus, if you want to come say hello, I am on TikTok. So I'm at Wendy Zuckerman, W-E-N-D-Y-Z-U-K-E-R-M-A-N.

We're also on Instagram, science underscore V-S. I'm Wendy Zuckerman. Back to you next time.