Are vegetable and seed oils \u201ctoxic\u201d?!<\/h2>\n
From TikTok to bestseller lists, vegetable oils\u2014a.k.a. \u201cseed oils\u201d\u2014are a big topic right now.<\/p>\n
To be fair, folks have debated the merits of vegetable oils dating back to when they first entered the marketplace.<\/p>\n
More recently, however, with the advent of the carnivore diet<\/a>, vegetable oil hate has roared back into the socials. Maybe you\u2019ve come across posts that refer to these cooking oils as \u201ctoxic sludge,\u201d \u201cmotor oil,\u201d \u201cthe hateful eight,\u201d and \u201cthe biggest cause of chronic disease that nobody knows about.\u201d<\/p>\n The anti-vegetable oil logic goes something like this\u2026<\/p>\n Animal fats have been with humans for thousands of years. Vegetable fats, on the other hand, were invented during the last century when profit-seeking companies wanted to find a way to sell cheap-to-grow foods to unsuspecting consumers.<\/p>\n Another argument: Like margarine, vegetable oils were marketed as healthier alternatives for butter, and yet, people argue, these oils are worse<\/em> than butter, raising your risk for obesity, anxiety, depression, ulcerative colitis, and more.<\/p>\n In contrast to the above line of thought, other experts will tell you that vegetable oils are harmless, potentially even health-promoting\u2014and absolutely better than butter.<\/p>\n So, who\u2019s right?<\/p>\n Like so many nutrition topics, the truth is too nuanced to fit on a meme. <\/strong><\/p>\n In this story, we\u2019ll help you sort the science from the pseudoscience so you can make informed decisions about the oils you choose to include in your diet.<\/p>\n Sometimes called \u201cseed oils,\u201d vegetable oils start, as you might suspect, from the seed of a plant. The most common ones you\u2019ll find in a typical grocery aisle include:<\/p>\n By the way, if you feel like there\u2019s a bunch of oils missing from that list, it\u2019s probably because those oils come from non-seed plants (such as olive, avocado, palm, or coconut oil, which all come from fruits, and aren\u2019t considered vegetable or seed oils).<\/p>\n Non-vegetable oils\u2014such as olive and avocado oil\u2014are derived from naturally fatty foods. In fact, olives are so oily that you could theoretically make your own olive oil at home. (Just Google \u201chow to make olive oil from scratch,\u201d and you\u2019ll find a number of videos walking you through the steps.)<\/p>\n The same can\u2019t be said of most vegetable oils, which mostly come from foods with a relatively tiny fat content to begin with.<\/p>\n Case in point: A cup of green olives contains about 20 grams of fat,1<\/sup> whereas a cup of corn has 2 grams.2<\/sup><\/p>\n As a result, manufacturers must use an extensive multi-step process to extract this small amount of oil from these non-oily foods. These steps include:<\/p>\n During this process, health-promoting polyphenols and other stabilizing nutrients are lost, and small amounts of unsaturated fats are transformed into trans fatty acids<\/strong> (also called partially hydrogenated fat).<\/p>\n (Interesting fact: This also happens during deep frying. When vegetable oils sizzle in a restaurant\u2019s deep fryer for hours, the trans fat content of the oil increases.)<\/p>\n To call these processed oils \u201ctoxic\u201d might be an exaggeration. However, nutrition scientists generally agree that people should avoid trans fats in the diet, and in 2018, the Food and Drug Administration banned manufacturers from adding trans fats to processed foods.3 4<\/sup><\/p>\n At PN, we\u2019ve created several visual guides<\/a> people can use to make informed decisions about what to eat.<\/p>\n (We\u2019ve also created a shopping list, which you or your clients can print out and take to the grocery store. Check it out: Healthy Fats Shopping List<\/a>)<\/p>\n In these guides, we\u2019ve placed a few vegetable oils\u2014expeller-pressed canola oil, high-oleic sunflower, and safflower oils\u2014in the \u201cEat Some\u201d section. For us, \u201ceat some\u201d is another way of saying that these foods will neither improve health nor harm health\u2014when consumed in reasonable amounts. <\/strong>In some cases, like in the example of dark chocolate, when consumed in small amounts, they might even improve health.<\/p>\n The rest of the vegetable oils, along with butter and other saturated fats, fall into the \u201cEat Less\u201d category, as the image below shows. You\u2019ll find vegetable oils in bold.<\/strong><\/p>\n<\/p>\n We\u2019ve gotten hate mail from folks who say certain vegetable oils\u2014especially cold-pressed canola oil\u2014should appear alongside olive oil in the \u201ceat more\u201d category. Plenty of others say all <\/em>vegetable oils belong in the \u201ceat less\u201d column, and that butter belongs in \u201ceat some\u201d or even \u201ceat more.\u201d<\/p>\n To understand the scientific reasoning behind our recommendations, let\u2019s explore some head-to-head matchups.<\/p>\n These oils are the least refined of their kind.<\/p>\n To make extra virgin olive oil (EVOO), manufacturers grind and mechanically press olives, without using any heat. Similarly, expeller-pressed canola oil is made by mechanically pressing rapeseed, without the use of heat or chemical solvents.<\/p>\n Olive oil is richer in heart-healthy monounsaturated fatty acids (MUFAs) than almost any other cooking oil.<\/p>\n In addition, unlike the more refined \u201clight\u201d olive oil, EVOO maintains most of the olive fruit\u2019s original polyphenols. These plant-based substances help to combat inflammation and protect cells from damage.<\/p>\n Perhaps most importantly\u2026<\/p>\n More studies vouch for EVOO\u2019s health-promoting qualities than for any other cooking fat.<\/strong><\/p>\n For example, researchers asked 22,892 adults from Southern Italy to self-report their olive oil consumption. People who consumed the most olive oil (more than two tablespoons a day) were 20 percent less likely to die over the 13-year study than people who consumed the least olive oil (less than one tablespoon a day).5<\/sup><\/p>\n Other research has linked the consumption of olive oil with a reduced risk of:<\/p>\n Consumption of olive oil is also associated with reductions in LDL cholesterol, especially when used to replace saturated fats like butter and coconut oil.10<\/sup><\/p>\n Years ago, culinary experts recommended using EVOO only on salads and other uncooked foods. Back then, they assumed EVOO\u2019s relatively low smoke point (350 to 410F) meant the oil would break down when heated, losing some of its distinctive flavor and <\/em>health benefits.<\/p>\n We now know that smoke point isn\u2019t as big a deal as previously thought.<\/p>\n That\u2019s especially true in the case of EVOO, whose polyphenols and high concentrations of monounsaturated fats help keep the oil stable when heated.<\/p>\n In research that heated a variety of cooking oils to 464 F (240C) and then held them at 356 F (180C) for several hours, EVOO remained more stable than any other oil tested, including canola oil.<\/strong>11<\/sup><\/p>\n<\/div>\n One of the more affordable cooking oils on the shelf, canola oil, is made from a Canadian-made hybrid of the rapeseed plant.<\/p>\n (The word \u201ccanola\u201d refers to the first three letters of \u201cCanada\u201d with a fun \u201cola\u201d added to the end for marketing purposes.)12<\/sup><\/p>\n Among vegetable oils, canola is the richest in heart-healthy monounsaturated fats (though several non-vegetable oils have it beat) as well as alpha-linolenic acid, a plant-based omega-3 fatty acid.<\/p>\n In addition, canola oil contains plant substances called phytosterols that help influence blood cholesterol for the better, especially when used as a substitute for butter, research has found.13 14 15<\/sup><\/p>\n Extra virgin olive oil is the clear winner.<\/strong><\/p>\n The body of research in support of EVOO dwarfs the body of research in support of expeller-pressed canola.<\/p>\n In addition, EVOO has a more favorable fatty acid profile. By the way, so does avocado oil, which is why you\u2019ll also find it in the \u201ceat more\u201d column.<\/p>\n However, you can buy roughly twice as much expeller-pressed canola oil for half as much money as EVOO. Because of this, expeller-pressed canola can be a good budget-friendly choice. In addition, because of expeller-pressed canola\u2019s more neutral flavor, many people prefer it over EVOO for baking.<\/p>\n When used in moderation, expeller-pressed canola can be part of a healthy diet. It is likely to be at least<\/em> health neutral, if not somewhat health beneficial.<\/p>\n This match-up comes down to how processing methods affect the end product.<\/p>\n An expeller press is a machine that squeezes oil out of seeds.<\/p>\n It\u2019s able to do this without the use of solvents or heat, which helps preserve beneficial compounds such as alpha-linolenic acid and phytosterols.<\/p>\n Refining removes some protective alpha-linoleic acid while adding small amounts of unhealthy trans fatty acids. This results in a product that is proportionally lower in omega-3 fatty acids and higher in omega-6 fatty acids.<\/p>\n Expeller-pressed canola oil wins, but only by a small margin.<\/strong><\/p>\n That\u2019s because canola oil starts with a less controversial fatty acid profile than many other vegetable oils, as the chart below shows. Soybean oil, for example, has less heart-healthy monounsaturated fat and much more theoretically<\/em> inflammation-contributing omega-6 fat.<\/p>\n The typical American consumes around 16 to 20 times more omega-6 fats than omega-3s.<\/p>\n This imbalance could theoretically<\/em> increase inflammation in your body, potentially raising your risk for diabetes, obesity, and other health problems, argue some experts.16<\/sup><\/p>\n Years ago, the recommendation to balance your omega 6s with omega 3s was widespread. (The suggested \u201cideal\u201d ratio: Anywhere from 1:1 to 4:1, in favor of omega 6s.)<\/p>\n These days, there\u2019s more debate among nutritional scientists as to whether this imbalance contributes to chronic inflammation, especially when those omega 6s are consumed in whole foods that contain many other beneficial compounds.<\/p>\n For example, nuts and seeds\u2014both naturally rich in omega-6 fats\u2014have been associated with a range of health benefits<\/strong>, including reductions in blood cholesterol and inflammation.17 18<\/sup><\/p>\n In 2019, Harvard Health ran the headline \u201cNo need to avoid healthy omega-6 fats<\/a>.\u201d In support of their argument, a 2019 study from the American Heart Association journal Circulation<\/em> determined that, if anything, the consumption of omega-6 fats reduced<\/em> the risk for stroke, heart disease, and early death.19<\/sup><\/p>\n However, while nuts and refined canola oil may share a somewhat similar fatty acid profile, the two foods differ in one important way. As we mentioned earlier, refined canola oil is basically pure oil. Meanwhile, nuts and seeds come packaged with health-protective fiber, polyphenols, protein, vitamins, and minerals.<\/strong><\/p>\n Minimally-processed foods, like nuts or extra virgin oils, include a complex matrix of health-promoting nutrients. Highly-processed oils, on the other hand, have lost the vast majority of those healthful compounds, leaving mostly just the fatty acids which are more prone to oxidation (we\u2019ll cover that next).<\/p>\n<\/div>\n This is the match-up that triggers the most arguing on the interwebs.<\/strong><\/p>\n Let\u2019s cover the major claims from both sides\u2014plus what the research says.<\/p>\n Butter proponents argue that saturated fats have been unnecessarily vilified. They point to nutrition recommendations during the 1980s and 1990s that recommended people replace butter with trans-fat rich margarine.<\/p>\n (We all know how that went.)<\/p>\n Margarine aside, others claim the research in support of reducing saturated fats is thin at best.20<\/sup><\/p>\n However, excessive saturated fat consumption (beyond 10 percent of total calories) does seem to boost cholesterol levels and may increase your risk of heart disease.<\/strong>21<\/sup><\/p>\n Some research has found that replacing 5 percent of the saturated fats in your diet with monounsaturated fats could reduce the risk of heart disease by 15 percent. Similarly, replacing 5 percent of the saturated fats in your diet with polyunsaturated fats (with most of that coming from refined vegetable oils) reduces the risk of a future heart attack by 10 percent, according to an analysis of eight studies involving 13,614 people.22<\/sup> Many other studies support this finding.23<\/sup><\/p>\n But not all saturated fats affect blood cholesterol equally. In some dairy foods, a membrane\u2014called a milk fat globule membrane<\/strong>\u2014surrounds the saturated fats and seems to limit their cholesterol-raising properties.<\/p>\n However, butter is low in this protective membrane, and consequently raises blood cholesterol more than other high-fat dairy products, like full-fat milk, cream, yogurt, or cheese.24 25 26<\/sup><\/p>\n The U.S. Dietary Guidelines recommend capping saturated fat at less than 10 percent of your calorie intake.<\/strong> A tablespoon of butter contains 7 grams of saturated fat\u2014a third of the recommended daily limit in a 2000 Calorie diet.<\/p>\n So, while you don\u2019t necessarily need to eliminate butter, it\u2019s worth moderating your intake.<\/p>\n (Interested in learning about all the nuances of saturated fat consumption? Read: Is saturated fat good or bad for you?<\/a>)<\/p>\n Due to their chemical structure, polyunsaturated fats are inherently less stable and more prone to oxidation than saturated or monounsaturated fats.<\/strong><\/p>\n During the refining process, protective phytochemicals and antioxidants are stripped, making these oils more prone to oxidation. The theory is that this oxidation increases inflammation in the body and elevates the risk of various health conditions.<\/p>\n There\u2019s some evidence to suggest that diets rich in polyunsaturated fats, especially from refined vegetable oils, are associated with increased levels of oxidized blood lipids, lipid peroxidation, and other markers of inflammation.27 28<\/sup><\/p>\n If you only use refined corn or safflower oils to lightly coat veggies before roasting them, you likely don\u2019t have much to worry about.<\/p>\n However, for the vast majority of people, the biggest source of refined vegetable oils isn\u2019t home-cooked meals\u2014it\u2019s ultra-processed foods. <\/strong><\/p>\n The extra processing and repeated heat exposure used to create ultra-processed foods further oxidize these oils. Additionally, these foods are often loaded with potentially harmful ingredients like added sodium and sugars, and low in beneficial nutrients like fiber, vitamins, minerals, and phytonutrients.<\/p>\n Plus, they\u2019re incredibly calorie-dense and difficult to stop eating, which can raise your risk for obesity. (Find out exactly why highly-processed foods are so \u201caddictive\u201d: Why you can\u2019t stop eating ultra-processed foods<\/a>.)<\/p>\n Most ultra-processed foods list one or more vegetable oils as one of their ingredients. Even ultra-processed foods that you wouldn\u2019t think of as \u201cfatty\u201d contain small amounts. You\u2019ll find them in store-bought cookies, chips, crackers, sauces, frozen dinners, meal replacement shakes, boxed macaroni and cheese, salad dressing, boxed rice blends, and more.<\/p>\n In a large review involving nearly 10 million people, the consumption of ultra-processed foods was associated with a higher risk of premature death.29<\/sup> In addition, studies have linked high consumption of ultra-processed foods with the following health problems:30 31 32 33<\/sup><\/p>\n You don\u2019t have to abolish ultra-processed foods.<\/p>\n But your health will benefit from capping your consumption to about 20 percent or so of your intake, with the other 80 percent or so from mostly minimally-processed whole foods.<\/p>\n This alone will naturally lower your refined vegetable oil intake to a safer level, without much fuss. Plus, consuming refined vegetable oils in the context of a diet that\u2019s rich in colorful plants, fiber, phytochemicals, and antioxidants may help offset the concern of oxidation. (For example, by putting a reasonable amount of commercial salad dressing on a large, colorful salad.)<\/p>\n This match-up is a draw.<\/strong><\/p>\n Ultimately, both should be limited in the diet, and neither are health-promoting.<\/em><\/p>\n Most refined vegetable oils are lopsidedly rich in polyunsaturated fatty acids compared to monounsaturated fats, and are stripped of many protective compounds. As mentioned earlier, some experts argue that these omega-6-rich fats may contribute to inflammation (but the evidence here is mixed). Because of how they\u2019re processed, seed oils also contain some of those trans fats that everyone agrees we should all minimize.<\/p>\n In contrast, butter is low in omega 6s but high in saturated fat, which can be problematic in higher amounts. Especially since it\u2019s so low in the protective milk fat globule membrane. However, compared to refined vegetable oil, butter is less processed. Like olive oil, it\u2019s one of those fats you could theoretically make at home.<\/p>\n This might be obvious from the head-to-head matchups, but we\u2019ll say it anyway.<\/p>\n If you like it and can afford it, EVOO is a great choice. <\/strong><\/p>\n Cold-pressed avocado oil and walnut oil are also great options, as both are rich in antioxidant compounds. Like EVOO, avocado oil is a rich source of MUFAs. Walnut oil\u2019s fat primarily comes from polyunsaturated fats, so it\u2019s best used as a dressing rather than used for cooking (as it\u2019s less heat stable).<\/p>\n However, like EVOO, avocado and walnut oil tend to be expensive. If you or your client are budget-conscious, expeller-pressed canola oil is a solid runner-up. <\/strong><\/p>\n Similarly, high-oleic sunflower and safflower oils are richer sources of monounsaturated fats than their high-linoleic cousins. When substituted for saturated fats like butter, high-oleic oils have been associated with cardiovascular benefits.34 35<\/sup><\/p>\n Regardless of what cooking fats you or your client choose, you\u2019ll also want to do the following:<\/p>\n Whole and minimally-processed foods\u2014such as nuts, seeds, avocados, olives, and salmon\u2014are more likely to feature health-promoting monounsaturated (MUFAs) and omega-3 fats. They also come packaged with a wide array of other good-for-you nutrients such as fiber, protein, minerals, and antioxidants.<\/p>\n In contrast, ultra-professed foods are generally devoid of everything you keep hearing you should consume more of. These foods also tend to be calorie-dense, highly rewarding, and hard to stop eating.<\/p>\n If you\u2019re not sure whether packaged food is minimally processed or highly processed, take a close look and consider:<\/p>\n If you answer \u201cno\u201d to most of the above, the food is likely highly processed.<\/p>\n It doesn\u2019t matter what source of fat is used to fry them.<\/p>\n Sort all fried foods into the \u201ceat less\u201d category.<\/p>\n EVOO is associated with longer, healthier lives. However, that doesn\u2019t mean you should be doing shots of it.<\/p>\n As a general rule, you\u2019re better off getting most of your fat from foods like avocados, olives, nuts and seeds than from any cooking oil.<\/p>\n Whole food fats are rich in fiber, phytochemicals, vitamins, and minerals, and are generally less calorie-dense than oils. (But having one to three servings of oils or butter per day is reasonable.)<\/p>\n And if you want personalized advice to suit your body, your eating preferences, and your goals, check out our Nutrition Calculator<\/a> to figure out how fats fit into your overall diet.<\/p>\n Click here to view the information sources referenced in this article.<\/a><\/p>\nWhat are vegetable oils?<\/h2>\n
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How are vegetable oils processed?<\/h2>\n
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What cooking oils should you eat?<\/h2>\n
Extra-virgin olive oil vs. expeller-pressed canola oil<\/h2>\n
\ud83d\udfe2 <\/strong>The case for extra virgin olive oil (EVOO)<\/h3>\n
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Smoke point: Should you avoid cooking with olive oil?<\/h2>\n
\ud83d\udfe1 <\/strong>The case for expeller-pressed canola oil<\/h3>\n
The winner<\/h3>\n
Expeller-pressed canola oil vs. refined canola oil<\/h2>\n
\ud83d\udfe1 <\/strong>Expeller-pressed canola oil<\/h3>\n
\ud83d\udd34 Refined canola oil<\/h3>\n
The winner<\/h3>\n
![\"A](\"https:\/\/assets.precisionnutrition.com\/2025\/01\/CookingFatsTable_v2.png\")
<\/p>\nAre omega 6 fatty acids \u201cinflammatory?\u201d<\/h2>\n
Refined vegetable oil oil vs. butter<\/h2>\n
\ud83d\udd34 The case for butter<\/h3>\n
\ud83d\udd34 The case for refined vegetable oils<\/h3>\n
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The winner<\/h3>\n
Some final parting advice<\/h2>\n
\u2705 Prioritize minimally-processed whole foods.<\/h3>\n
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\u2705 Limit deep-fried foods.<\/h3>\n
\u2705 Get most of your fats from food, not oils.<\/h3>\n
References<\/h2>\n