The Vegetable Oil Myths You Still Believe

The Vegetable Oil Myths You Still Believe

Producer Potts: 0:13 Hit me, Producer Pots.

The one thing everyone seems to agree on in health-conscious communities is that vegetable oils are toxic and inflammatory. Where does this myth around industrial seed oils come from?

Dr. Sarah 0:30

The myth comes from mechanisms identified in rodent and cell culture studies that make a lot of logical sense on the surface—if you just look at what could happen, assuming that’s the only thing going on, and ignore all the studies in humans, along with the complexity that happens in humans. There’s an incredibly huge depth of scientific evidence showing that not only are vegetable oils not toxic, inflammatory, or likely to increase cancer risk, diabetes, or cardiovascular disease, but actually the opposite: consuming vegetable oils is associated with health benefits.

Producer Potts 1:35

Okay, say more.

Dr. Sarah 1:37

Vegetable oils have one really important thing in common—they’re all high in an omega-6 polyunsaturated fatty acid called linoleic acid. The effects of linoleic acid are behind most of the myths about vegetable oil because linoleic acid can basically be turned into a couple of different things in the body. So, I think it’s whiteboard time.

Linoleic acid, the main fatty acid in vegetable oils, can be turned into what are called oxidized linoleic acid metabolites, or “oxlams” for short. High production of oxlams does increase inflammation and has been associated with an increased risk of chronic disease. Linoleic acid can also be metabolized into another omega-6 fatty acid called arachidonic acid, which, in high amounts, does increase inflammation and has been associated with increased chronic disease risk.

So the fact that we see that linoleic acid can increase ox lambs and arachidonic acid in simpler systems, so like in cell culture systems in basically in test tubes, has led to the idea that, well, therefore, if we consume a lot of linoleic acid, that would increase inflammation and chronic diseases associated with inflammation. The other sort of evidence going into this hypothesis was that vegetable oil consumption increased as a fraction of total caloric intake pretty dramatically over the last 100 years, and in a way that correlates with increased incidence of cardiovascular disease, type two diabetes and cancer. Correlation is not causation. However, it does show us that this might be something that’s interesting to explore, and the existence of these possible mechanisms that could potentially explain causality, that makes it even more interesting to look at. But here’s the thing, when we actually look at studies in humans, we show a couple of really important thing. So first of all, high intake of linoleic acid does not actually affect the levels of arachidonic acid in the body. So there’s been studies where they feed people very, very high amounts of vegetable oil and then measure how much arachidonic acid they have in either tissues or blood, and show that that that one does not necessarily lead to the other, and especially if we’re consuming enough omega threes that changes how much linoleic acid is turned into arachidonic acid. But then there’s an extra layer of complication. So first of all, we can say that this is not actually necessarily true. But the other thing that’s really interesting is that studies where they have given people arachidonic acid, so not linoleic acid, not the fat and vegetable oils, but the suspected culprit, de. Directly have also shown that this does not increase inflammation. So these arrows of these possible mechanisms actually fail in both both points. So we do not see that linoleic acid increases arachidonic acid. We also don’t see that arachidonic acid directly causes inflammation.

Producer Potts 5:37

I mean, that’s really fascinating, because basically what it made sense that everyone thought that vegetable oils were harmful, because that’s what we saw in those rodent studies. And now in these human studies, we see it doesn’t actually work the same way in our bodies. That’s fascinating. Okay, sorry, I didn’t mean to interrupt you. Keep going.

Dr Sarah 5:43

This is great. I think that’s important, an important commentary, because the the root of these myths is like, there’s, there’s scientific truth there, right? There’s studies that that are showing mechanisms that could potentially be cause of concern. It’s just that we’ve got this huge collection we’ve got now these, you know, very, very large systematic reviews and meta analyzes that pool together data from many, many different clinical trials in order to increase statistical power as well as reduce bias. And they show that there’s basically no effect of linoleic acid on inflammation, or actually a slight reduction of inflammation when we consume linoleic acid.

Producer Potts 6:35

Now, one quick question before we move on: when you say bias in studies, does that include funding and conflicts of interest? Because I know that comes up for a lot of people.

Dr. Sarah 6:43

Yes, so in a meta analysis and a systematic review, one of the steps is to evaluate studies quality, and so that looks at funding sources, that looks at conflicts of interest, but it also looks at things like potential sample bias, so do we have the right type of like demographic representation in the control group as well as the intervention group? Right to those groups match, are the controls, the appropriate controls. It also looks at the types of measurements that are made. So some measurements are just more trustworthy than other measurements, right? They have less ability to be influenced, say, by a scientist expecting a result, and then, because they expect the result, they see the result, right? So if you are looking at something where you’re just going to be like, you’re going to look at it, and you go, yeah, that looks, you know, that looks more blue than green to me. And when we’re talking about something that’s teal, right? If I’m expecting it to be blue, I might see it blue, because that’s my expectation. So in science, we try as often as possible to do things like blind so the person in the intervention group doesn’t know which group they’re in, and the scientist looking at the data doesn’t know what group they’re in, so that we can get rid of that potential effect. So blinding can help get rid of that effect. And then types of measurements where you where they’re like, quantified, right? So you take a blood sample and you look at cholesterol that the scientists running that test can’t change the results of it because it’s measured by a machine. So looking at the types of tests that are run to make sure that they’re things that are quantified where there’s no ability for the person running the test to bias the results. That’s another thing that’s looked at, and then looking at things like statistical power. So how you know how big are the sample sizes? How long are they followed? What how much data is there here? That’s another part of systematic reviews.

And then when all of that data is pooled together, you end up with really high statistical power, because it’s, it’s like, you know, a systematic review that looks at 40 different studies. Those 40 studies all had to have grant funding, right? You know, it costs money to run that, you know, blood cholesterol measurement, it takes money to have, you know, study participants, come into an office and have tests done, and it costs money to run the tests, to do the analysis, it costs money to publish. So those are funded by grants. And the research that I am looking at is the research that is funded by grants not funded by industry. So it’s it’s funded by things like the National Institutes of Health, which is a you know, agency designed to help support science for the sake of science that doesn’t. Of ties to any industry or organization that might might bias the results, so that is all accounted for in these analyzes. So we can put a much higher amount of trust in the results from systematic reviews and meta analyzes than any one study, because the other thing that they’re doing is they’re showing us where the preponderance of evidence is. So where, where do most studies point like a small difference in study design could end up changing the final measurement, or a different study population could end up changing the final measurement. So it’s kind of expected when you have a lot of different studies that are all designed at answering the same question, it’s expected in science that they might not all agree there is a randomization effect, there is a sample bias effect. And so what systematic reviews and meta analyzes do is they look to where the entire field of scientific literature, all of the good quality studies that are designed to answer this question, what do they all show together when you kind of look at this big picture? And that’s also really important, because if you, if you it’s called cherry picking, right? So you can look for that one study that agrees with you. If that one study shows something opposite, then another 39 studies out of 40, it’s probably not the one showing the actual effect. It probably there’s probably something else to explain why that result was different. You know, some kind of luck of the draw, causing some kind of difference in the sample population that’s in that study, some kind of flaw in the measurements, right? Something happened to make that not align with everything else. But what is really, really common in conversations about vegetable oils online is that cherry picking, looking at cell culture studies and rodent studies that show these mechanisms, and ignoring the human data, or finding that one human study that shows whatever the narrative is spreading fear about vegetable oils and ignoring the 39 others, or, even more importantly, ignoring the meta analyzes and systematic reviews that show where the totality of evidence is, which is that vegetable oils are beneficial.

Producer Potts 12:31

I’m so sorry I sidetracked you, but I’m so glad you explained all that, because on social media everywhere, it’s like, that’s what everyone says. Well, it was funded by big food or Big Pharma or like this, you know, evil large corporation that’s running the entire world and like, that’s just leaning into conspiracy thinking when you, like, take yourself a step out of that kind of argument to learning something new. And like, I’ll just say, I’m gonna let you get back to what you’re saying. It’s fascinating. But I’ll just say, like, it’s okay to appreciate new information, learn something new, even if that doesn’t mean it changes your own personal habits. It’s okay, right? Like, and I think, like, I think that a lot of people take it as a personal attack on things that they believe to be true, versus just having curiosity about life, right and like, I think we just need more curiosity on the internet and less like, you’re wrong and you’re right, right or whatever, because, like, you know, anyways, okay, I’m gonna let you I distracted you long enough. Okay, I’m gonna let you get back to this, because this is fascinating. Put you back to your whiteboard.

Dr. Sarah 13:46

I think I do want to emphasize one of the things that you just just alluded to, which is, I used to believe that vegetable oils were inflammatory. This is a very easy to believe myth because of these mechanistic explanations, and because for a long time, we had more data from these types of studies, cell culture studies and rodent studies than we had from human studies, the human studies that have really put the nail in the coffin of these vegetable oils or bad myths, most of them come from the last 10 years, and so it’s it’s also understandable that these myths took hold in part because we want someone to blame, right? We, we, we want to have nefarious actors that we can point the finger to for the high prevalence of chronic disease in our country, and because this science sounds so logical, because there’s this mechanistic explanation, it’s it’s a it’s a really easy myth to to buy into. So as somebody who also had to work really hard, and because I came at this with a huge amount of skepticism, I’ve done an even more sort of rigorous relook at the more up to date science in order to shed a myth that I used to believe and bring this higher quality information to you. But also, I mean, I think, as we talk about this, I hope, I hope we can not just stop you from being afraid of vegetable oils, but maybe encourage you to add some, because we’re, I think we’re gonna, we’re gonna have to talk about canola oil and how uniquely beneficial it is. I think that’s maybe a can of will do another video, yeah, maybe not. I still, and we’ll have so much on this one, so, and also, I think people are probably already thinking about that viral video. We know which one we’re all thinking about, if you’ve been in the wellness industry. And I think we’ll address that on a separate video too, because I think the processing and the quality of the oils is like another whole conversation. Anyways, okay, let’s get back to the whiteboard. And I’m sorry, but I felt like that was like, because I could just hear that’s probably what people were thinking. Because that’s what I you know what I mean. So anyway,
I mean, that’s the thing, right? Is that the vegetable myths that are out there are so deep, right? They they have, you know what look like scientific explanations and evidence to support them. There’s studies from the 60s and 70s that look like they support them. That’s probably another whole other video. This is probably the beginning of a giant video series, I think, is what I’m saying. But I think, I think let’s focus on on the mechanisms as the roots of of these myths, and why? Why that’s that’s not the case. So let’s talk about ox lambs, the oxidized linoleic acid metabolites. So the concern is that increased ox lamb production can lead to atherosclerosis and can potentially increase the risk of cardiovascular disease, and that just having more linoleic acid in our bodies can make our LDL cholesterol in our blood more susceptible to oxidizing, again, leading to atherosclerosis and cardiovascular disease. But what’s interesting is that the early studies that looked at how consuming vegetable oil, meaning eating more linoleic acid impacted the oxidizability of LDL particles right increasing ox land production. They compared linoleic acid to oleic acid, the main monounsaturated fatty acid in olive oil, and what it looked like was, ah, linoleic acid, terrible. But subsequent studies that have actually now compared linoleic acid to omega threes, to oleic acid and to saturated fat, actually, what they show is that there’s no difference. So linoleic acid, omega three fats, right? Omega six, omega threes, saturated fat, they all kind of create LDL particles that have the same susceptibility to oxidation. It’s oleic acid that is uniquely beneficial, not linoleic acid that is uniquely bad. Fascinating, okay, wow, mind blowing. This is so cool. Definitely giving a lesson today. We’re going to add another, another. This right, actually sort of happened, but there’s this extra, really interesting factor, which is that what is controlling the production of oxidized linoleic acid metabolites from linoleic acid is the availability of vitamin E. Vitamin E is a fat soluble antioxidant, and so studies show that as long as we’re getting enough vitamin E, we don’t need to worry about this pathway at all. So another like pro column check mark for making sure that we’re getting all of the nutrients our bodies need. Yeah, exactly following a Nutri more eating like a Nutri more exactly, love that. That’s great. So I’m going to make things one more step complicated. Well, we’re already here. Let’s go. The extra step of complication is these are not the only two possible fates of linoleic acid in our bodies. Linoleic acid can also be turned into gamma linolenic acid, which can then be turned into a di homo gamma linolenic acid, which is an incredibly beneficial, anti inflammatory fatty acid. In addition, what controls whether or not linoleic acid is turned into arachidonic acid or di homo gamma linolenic acid in the body is a bunch of nutrients, including omega three fats. Stick a pin in that, because that’s going to be important, as well as zinc. So much so that measuring dgla in in the blood can be used as a proxy for measuring zinc deficiency, magnesium, vitamin C, vitamin b3 and vitamin b6 yet another check in the pro column for getting all of the nutrients our bodies need from the foods we eat, because it changes how linoleic acid is used to produce although we’ve already covered the science showing that this doesn’t directly lead to increased inflammation, but when you have all of these other nutrients in the diet, we’re actually turning linoleic acid into something that is anti inflammatory, which is why we have this growing body of clinical trials in humans showing that increased vegetable oil consumption either has a neutral impact on inflammation or lowers it.

Producer Potts 21:36

This is so amazing, and I think like wrapping your head around vegetable oils, like not being bad is one thing. Wrapping your head around vegetable oils being good is another thing. So I think we need a separate video on that. But also, like, there is, like, this little bit of like, maybe not little I think again, like you said, this is like more pros in following a nutrient focused approach when making food choices, eating like a nutrivore. But also, you know, when you go out to eat, if you are a very health conscious person, you may have gone to the links to be like, what kind of oil do you use in your fire? You don’t have to ask that annoying question anymore. And if you were eating a nutrient focused diet, which you’re already a health conscious person, you probably already are, you are actually getting a benefit when you have that meal out and enjoy and you don’t have to like stress about it. Just that little tiny piece is so amazing. You’ve just blown my mind. This is great. I am very distracted right now because somebody came to say, Hi, oh, hey, there. Oh, you’re getting white all over my shirt. All right, I’m gonna, I’m gonna evict you. Dr, Sarah, you just gave us all so much mind blowing information, it’s a lot to wrap our heads around. So I think we should do a couple more videos and dive into these a little bit deeper. And also we need to talk about omega threes to omega six. That’s going to be another video, because you said put a little pin in that. So I know that means that you have more to share on that. So what is your take home message to someone just new, newly hearing this information and having like this is a lot to digest. So what’s your what’s your what takeaway do you want people to have from this video essentially?

Dr. Sarah 23:39

The most important takeaway is that despite all of the scary language that is used around vegetables, seed oils, industrial seed oils, industrially processed seed oils, all of that is designed to spread fear, and that is not what the scientific evidence supports. The scientific evidence supports vegetable oils as being beneficial, lowering cardiovascular disease risk, lowering risk of total mortality, risk of type two diabetes, risk of metabolic syndrome, and potentially even lowering risk of breast cancer. So vegetable oils are actually a health promoting food, and one that not only should we not be afraid of it, you know, actually maybe mixing up the oils that we’re using in the kitchen may actually be beneficial to our health. So this is a myth that actually makes us scared of a health promoting food, and that’s why it is so important to bust.

Producer Potts 24:42

Thank you, Dr Sarah, for really blowing all of our minds today. You have a super in depth article on vegetable that I will make sure is put here so you can find it if you want to read that and really dive into the studies. I know many of you are probably going to leave comments on this video. That’s okay. Chin. Make sure they’re kind and lead with curiosity. That’s all I’ll say. So thank you so much. Dr, Sarah, wow. My My mind is blown. My mind is blown. Thanks.

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