What does the science actually say about seed oils?

I’m so sick of talking about these I made AI write this:

In this episode, Jono discusses seed oils and addresses the claims made about their health effects. He explains what seed oils are, where they come from, and the major claims against them. Jono debunks the idea that seed oils are unhealthy due to their production process, highlighting that the evidence does not support this claim. He also examines the link between seed oil consumption and inflammation, concluding that the evidence does not show a significant impact on inflammation in humans. Additionally, Jono addresses the claim that seed oils are responsible for obesity, emphasizing that it is the overall energy intake and food environment that contribute to obesity, not just seed oils.

Hey, that’s actually not too bad! Please enjoy


Time Stamps

00:00 Introduction to Seed Oils
06:03 Examining the Link Between Seed Oils and Inflammation
14:20 Understanding the Role of Seed Oils in Obesity


Welcome back to the Bite Me Nutrition podcast. Today we have a doozy of a topic. We're gonna be talking about seed oils. Now for a few of you lucky ones, you fortunate people who have avoided the dark corners of the internet, you're probably thinking what the hell is a seed oil? And I will cover that, but unfortunately, I feel like most of us have probably come across someone making some pretty extreme claims around the health of seed oils and foods that contain seed oils. And so I want to use this podcast to go through what these claims that, well, firstly, just to tell you what they are, what seed oils are and where they come from and all these sorts of things. Uh, but then also go through some of the major claims that I've heard people make about seed oils, unpack the evidence behind these claims, uh, to see if it's something that you need to be worrying about in your diet. Um, they like, there's definitely certain tribes will call them on the internet, uh, in the nutrition space that are very anti seed oil. They also typically have a few other nutrition views, which are questionable, but we'll go through that as well. And even though some of you mightn't have heard of seed oils, this stuff is becoming more and more sort of pervasive and more mainstream, if you will. I was in Byron Bay a while ago now, maybe six months ago. And if you're from Byron Bay, please don't take this the wrong way. Obviously it's an absolutely stunning part of the world, but some of the health ideas that come out of there can be a bit interesting. I remember we got breakfast there and the bottom line of the menu on the cafe, cafe said something like, uh, proud to be seed oil free or certified seed oil free or something like that. So even cafes are now, um, making this claim. Uh, I know up where I live on the sunshine coast, there's a certain cafe that has, um, been consulted by a health influencer, which is, that's a depressing sentence, but t hey are also seed oil free because this person has in their head that seed oils are bad and obviously has a relationship with the cafe. And here we are. So seed oils are derived or extracted from seeds. I know, I know. I bet you couldn't have figured that out on your own. So thank God I'm here. But the most common ones that we're going to see, at least in Australia, are things like sunflower oil and canola oil. Um, you know, a common one I use cooking is sesame oil incredible in Asian cooking. But I would say sunflower and canola are probably the two most commonly used ones. They differ from things like avocado oil or olive oil because of like avocado and olives are fruits. So they technically don't count as seed oils, right. And they're all also, of course, quite different from things like butter or ghee or coconut oil, also a fruit. And so, yeah, it's this kind of subset of cooking oils that have been derived from seeds. There's kind of three main claims I think I hear about them or problems that people have with them. Um, the first is down to the way that they have been produced. Um, Yep. The way that they have been produced. Uh, the next is kind of this big, I guess, talk discussion around their, their promoting inflammation, which in turn, uh, increases your risk of disease and cancer and death and these sorts of things. So kind of a big pathway there. Uh, and then the other big claim I see is that they're, uh, they're promoting obesity or they're responsible for obesity. So I want to unpack each of those three. Uh, I'm going to start with the easiest one. Um, the, you see all the time that they are industrial oils that they were, they're, you know, very highly processed and they were made in a factory. Um, and they were used initially for lubricant, which like, I don't really know why that matters to be perfectly honest, other than it's a very, very excellent example of something called the naturalistic fallacy, which is a thinking kind of error that we can fall into, which is this idea that things that are natural are safer and better for us and things that are unnatural, which is not always the case. An example that gets thrown out all the time is like cyanide is natural, but clearly not very good for us, right? Same as bears. So like just because something is natural, it gives you no bearing on whether it is good for you or not. And so the fact that these are quote unquote, unnatural is irrelevant, right? What we want to do is we want to always be referring back to the studies and the information that we see there. So one of the things that comes up is there's a compound called that production and people go on about hexane being really bad for us. But the reality is hexane as a compound is very unstable, which means that after that process, there's going to be very, very little left in the residue, it's all going to decay and degrade and disappear. So the likelihood that your seed oil is high in hexane is slim to none. You get more hexane from exhaust, you know, like walking in the city getting it inflammation. And then of course, you know, high levels of inflammation increase our risk of disease and cancer and that bit is true, you know, high levels of chronic inflammation are not ideal and are definitely not something that we want to be seeing in people. But the part where it breaks down is when they talk about the link between seed oil consumption and higher levels of inflammation. Where this comes from, well, to understand where this comes from, we need to just talk about the different types of amigas. So the fatty acids in our diet. Probably the two most common ones and I'm sure a lot of you have heard of like Omega-3s. These are your polyunsaturated fatty acids. They're predominantly found in fatty fish and then nut seeds and olive oil contain them as well. The name Omega-3 is just kind of reference to its chemical structure. It's like where the double bond is in the carbon chain. It's three from the terminal end. That's so unimportant. That's just me trying to blow the cobwebs off my biochemistry from uni. But that's the name. That's where the name Omega-3 comes from. And then we also have omega-6 fatty acids, which are monounsaturated fatty acids. Again, the name is due to their chemical structure. They are often also found in seeds, obviously, and nuts and fatty fish and olive oil as well. They contain all of these fats, just kind of in different ratios. So when you hear someone say that salmon is a good source of omega-3s, it's not that it doesn't contain omega-6s, it's just that it's got predominantl and then of course we have saturated fat, which I think is omega-9. I should know that, but I don't. But saturated fat is the other predominantly, yeah, the other main source of fat, oh, a lot of keys. The other main source of saturated fat, the other main source of fatty acids. And finally we have trans fats, which fortunately we don't have to worry about too much anymore. They've, we're working to, I'm not working, but they are working to eliminate them entirely from food production and they've done a pretty good job of it, so. Anyway, there you go. Omega-3s and omega-6s. They're the two most common ones that we're gonna be talking about in this scenario because seed oils are very high in omega-6s. And there's this idea that a high intake of omega-6 can increase your inflammation. And in particular, your ratio of omega-3s to omega-6s can be pro-inflammatory if that ratio is out. I actually remember learning about this at uni. They taught us about this ratio in uni, but I'm not sure if... what I just got taught was wrong or if more evidence has sort of come out since then. Um, but it looks like the, this ratio is actually not very relevant because on the Omega six side of the ratio, it doesn't seem to matter how high that Omega six intake and therefore our Omega six status is people with high Omega six statuses can still be perfectly fine and healthy. If their Omega three and Omega six status is sorry, if their Omega three status is healthy or optimal. And so it's less about this ratio and more just about making sure you've got enough omega-3s. And so it appears that if you've got adequate amounts of omega-3s, the omega-6 intake is not super relevant. In fact, there's quite a few studies showing that a higher intake of omega-6s can actually be beneficial. So I think one of the suggested reasons why omega-6 is inflammatory is because of it's, there can be a conversion to something called arachidonic acid, which is pro-inflammatory, yes, but there's no evidence to suggest that humans develop this really high amounts of systemic, so all over our body, arachidonic acid. All of these claims are coming from, they're either theoretical, like so mechanistic studies or they're in rodents in particular. There's no evidence to suggest that they are inflammatory in humans. And you're going to get sick of me saying that phrase in humans, because that is a theme that's going to continue with this in all of these discussions around seed oils. I'm yet to see someone put forward a good study in humans. They're either complaining because it's industrial lead produced, or they're talking about all of these studies and mechanisms that we have not been able to observe in humans. Um, I've said it before. I've made the joke many, many times, but if you're listening to this, you're probably not a rodent. And so whilst rodent studies are important for developing hypotheses, and they're an important part of the scientific method, I'd be very careful using a rodent study to influence the way that you eat, i.e. I wouldn't. So in terms of that ratio, haven't seen any reason to suggest that it is a problem. We haven't seen any reason to suggest that a high omega-6 intake is an issue in humans. In fact, we've actually got quite a few studies showing that groups of people have higher intakes of seed oils in particular, canola oil, like I said, that's a common one. So that's been studied pretty thoroughly. We see these in these big groups of humans with that consumption, either in a neutral or potentially even a slightly positive impact on their health, which is obviously quite different from what you've been hearing about seed oils, but here we are. And the criticism of these studies is often that they're big cohort studies, they're longitudinal studies. So they're not, they're what's called free living studies, right? That we haven't put locked someone in a lab and controlled everything they've eaten. So yes, there's a lot of other variables that could be going on in their diet. First of all, these studies run for like five plus years, which is great because a lot of things in nutrition take a lot of time to develop, right? Something could be incredibly damaging for you, but if you eat it for a week, you could still be fine. So that is the... how that's why these studies are helpful because they give us a longer range version. But also you can't like that. You can't lock someone in the lab for five years and control everything that they do. That's prohibitively expensive. So it's very idealistic, but we just can't do it. So we need to use these studies. And the reality is we can do a lot of clever. I can't do it. Clever people can do a lot of clever statistical analysis to kind of remove out these other variables to make sure that the results that we're seeing aren't due to other things. Like they're not due to things like their alcohol consumption, their smoking status, their sedentary lifestyle, these sorts of things, right? So we can control for these variables and we still see this either neutral or slightly positive impact on people's health with a high or moderate to high consumption of seed oils. So either seed oils aren't a problem or they are a problem, but these people are also doing making so many other positive nutrition choices that it's outweighing their seed oil consumption. I know which of those two scenarios sounds more likely and looks like the people writing the studies agree with me or rather I agree with them, which is great. Um, so we do have a, like quite a big evidence base of human data showing that moderate to high intakes, you know, just normal intakes of seed oil consumption are totally fine. Whereas I am yet to have someone show me a study in humans, there it is again, showing that a higher omega six or a higher seed oil consumption has negative outcomes. Even if I saw that one study, it would have to be a pretty epic study to start to completely change my view, not because I know that sounds really bad, hey, because the scientists are supposed to be flexible. But we also need to make sure we're talking about the Oh man, the evidence as a whole, right? So even if one study comes out showing the opposite, that's gonna be really interesting and I'd be keen to read it and dive into that. But the fact that it's one versus a whole host of other studies still shows that the body of evidence, the weight of the evidence, that's what I was looking for, suggests that seed oils are safe. But if you've got that study, or if a friend has a study, please let me know, because it, yeah, be really interested to read it. Don't think I'm gonna get anyone sending me a study though, because I don't think it's out there at this stage. So what's next? Oh, yes, obesity. This is the last one. So a lot of people blame seed oils for obesity. I've seen people even saying that it is the cause. It's not sugar. It's not our sedentary lifestyle. It's not the fact that calorie averages of fast food have like doubled or something in the last 20 years. It's not food security, food access, food literacy. It's not your socioeconomic status. That's not, it's nothing to do with any of those things. It's not the food environment that we in, it's actually just seed oils, right? People are actually making claims like that. It's insane. So, um, to boil down, you know, the very, very complex scenario that is obesity to one factor. So if someone's doing that, you know, automatically, please just ignore them, unfollow them, um, clean up your feed. But one way I suppose in which a seed oil product could promote higher body fat levels is because a lot of ultra processed, highly energy dense, highly palatable foods do contain some seed oils, right? I know I just said ultra processed and that's a controversial topic because I don't really like people talking about ultra processed foods as being the devil because it's a very broad spectrum, yada, yada. Instead, please replace ultra processed with highly palatable energy dense because those are the foods which if over consumed can be problematic and they're easy to over consume because they're highly palatable right? They're delicious. And so if you have a pack of Tim Tams with a seed oil in it, and you eat the whole pack Tim Tams because they're delicious. And you are consistently eating higher intakes of these foods, eating the whole packet of chips because they're delicious, you're eating the whole pint of ice cream because it's delicious. You're probably not going to have seed oils and ice cream, but you know, you get my point. Is it really the seed oil that's driving that person's excess body weight? Or is it maybe the just higher energy intake overall? Right. We know that, uh, body to gain body fat, you need to be in a calorie surplus. You need to be eating, consuming more energy than you were burning. Um, seed oils don't break that law. They can't break the first law of thermodynamics. Um, but highly palatable, energy dense foods make it a lot easier to eat in a surplus. So, in the case of the obesity, I don't think it like you could replace every single seed oil in those foods with olive oil, which is very, very healthy oil, still my favorite oil, by the way, I'm not saying like I would still recommend people go for olive oil if they can. But if you did that, it wouldn't change the energy density of that food, people would still overconsume it and we would still have the exact same outcome. It's not the seed oils, it is the all of those other factors and more that I mentioned that are kind of contributing to this obesogenic environment that we are living in. So again, if someone's got a study, they won't. I'm just so sick of talking about it. But anyway, I think that's inflammation, industrial obesity. Cool. So I guess sometimes the question I get then is like, yeah, but like, Jonah, does it matter if... If I avoid these foods, like why is this a problem? Because like I said, they're not going to like significantly improve your health. They either have a neutral to like maybe a mild positive impact like I spoke about, but I think it's probably more likely that on the whole, they're neutral. So, you know, if I want to avoid them, what's the problem? And for the individual, that might be okay. But what's really important to remember is more than anything, they're very cost effective.  Like I said, my favorite oil still is olive oil because it's the one with actual legitimate health benefits. But a bottle of canola oil compared to a bottle of olive oil, it's like a 10th. That's not true. It's probably like a fifth of the price, I think, last time I checked. It's so much cheaper. It's very cost-effective. And obviously at the moment, financial environment is pretty cooked. And so for a lot of people, that olive oil might just be one of the things they have to cut. And then their canola oil though is very accessible and they may eat being made to feel scared and guilty about purchasing this unhealthy, damaging oil, which is just not true. But obviously, they're not going to feel great about that, are they? And as we know, shame and guilt aren't the most helpful emotions when it comes to making healthier food choices. So that's the first thing, the very cost effective seed oils are very cost effective. So making people afraid of them is pretty elitist, which is so weird in the wellness space. Hey, we never see any elitism going on. And certainly no privilege. But the other thing that often happens, and I would say this is one of the worst things, is that people are often encouraged to replace seed oils with unhealthy oils, right? And fats, the groups I spoke about before with the other questionable beliefs, so usually anti-seed oil, but very pro butter, and tallow and lard and ghee and coconut oil. And these fats are... very high in saturated fat, right? And we know that saturated high intakes of saturated fat increase our risk of cardiovascular disease, which is the number one killer in the world. So telling someone to replace a cheap, neutral, neutrally health impactful oil with a potentially health damaging oil, hopefully you can see why that is potentially a huge problem. And so, that's another issues people are going to. Look, if you're replacing all your seed oils with olive oil, that's totally fine. If you're replacing all your seed oils with butter or ghee or coconut oil, that could be problematic. So that is another scenario that grinds my gears when it comes to seed oils. I think the last thing as well is just, if you're not careful, if you go to scorched earth on your Omega-6 intake, you can eliminate a lot of really, really healthy foods. So a lot of nuts, you know, walnuts. almonds, and then obviously chia seeds, hemp seeds, all of these foods contain omega sixes. And then there's even some healthy packaged foods that contain these seed oils specifically, I know one of the air popped popcorn brands that I love contains a little bit of sunflower oil, you know, and people would be avoiding that because it's a seed oil, right? Despite the fact that popcorn is incredibly rich source of antioxidants, a fantastic source of fiber, it's a really satisfying relatively low calorie snack. It's got so many good things going for it, but it's got a little bit of sunflower oil on it. So depending on who you've been listening to on the internet, you might be afraid of that and you might avoid it and remove this incredibly like cost-effective and nutritious food from your diet. So while removing seed oils on the individual level, you could do it in a way that doesn't damage your health and hopefully keeps your mental health intact, but for a huge amount of other people and the public as a whole, I very much don't think that's what's going on. You know, I've seen people complain, like Oatly, I think has sunflower oil in it. And so, you know, that milk is poisoned because of the seed oils. Like it's just, it's wild out there. So. I guess that's all I've got to say about seed oils, which is more than I've had to say about any other topic actually. This has been my longest solo podcast. Oh no, it's happening. I'm ranting, but I'm gonna shut up now. Hopefully that's answered your questions about seed oils. If it hasn't, please reach out and let me know what the other questions are that I've missed so I can cover them. I would love for you to send this to your favorite carnival bro, or your favorite paleo bro, all those people that are scared. It's actually not, I know we pick on bros, but there's... bloody ton of whatever the opposite of broke gal. I don't know. There's a lot of people talking crap about this topic. So stay safe out there. If you see someone demonizing seed oils, please unfollow them. I don't care if they've got good recipes. I don't like just get rid of them. They're going to start making you afraid. They're going to give you more and more nutrition misinformation and they're going to confuse you, which is one of the most dangerous things. So please get rid of them. Have a listen to this podcast. All of the references to those studies, of course, will be in the study notes. Don't take my word for it. I'll put them there so you can read them yourself and see the hard data. And I will talk to you next time.