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I’ve been a dietitian for nearly 20 years, and I’ve seen a lot of nutritional villains like trans fat, sugar, and sodium face public scorn.
But seed oils? I didn’t see that one coming. And frankly, I’m still puzzled as to how these oils have gotten such a bad reputation.
If you’re wondering whether you should avoid seed oils, here are a few things you should know:
What are seed oils?
Seed oils are technically any oil that comes from the seed of a plant. But eight seed oils in particular are getting bad press lately: canola, corn, cottonseed, grapeseed, rice bran, soy, sunflower, and safflower.
Why so much hate?
Haters point to a couple of concerns about these oils. First, they’re refined, which involves treating the oils with heat or chemicals to take out impurities. Critics say this creates harmful compounds and renders them ultra-processed.
These oils are also rich in a kind of polyunsaturated fatty acid called omega-6. Some say eating these oils creates an unhealthy balance between omega-6 and omega-3 fatty acids (which are found in foods like salmon and flaxseed) that could lead to inflammation and chronic disease.
Where do we get seed oils?
Some people may keep these oils in their cabinets for cooking and baking. But you’ll find those eight targeted seed oils most frequently in processed food, including ultra-processed food, which is food that tends to contain more additives and is farthest from its original ingredients (think chicken nuggets, donuts, and gummy fruit snacks).
What’s the problem?
There are a few issues with the arguments against seed oils. For one, polyunsaturated fatty acids, including omega-6s, aren’t dangerous and have actually been shown in research to be heart-healthy, especially when used in place of solid fats like butter and lard.
And second, are we getting seed oils by sauteeing vegetables in a drizzle of canola oil? Or are we getting them via a diet high in ultra-processed foods, something that’s been shown to be hard on health–not because of the specific oils used but because those foods tend to be high in fat, sugar, and sodium and low in healthful nutrients like fiber and vitamins? That should be the focus.
What should you do?
I’ll tell you what I do: I use a variety of fats and oils. I make cookies with butter, roast veggies in olive oil, pop popcorn with canola oil, and use avocado oil, sesame oil, and other fats depending on what I’m making. And with all fats and oils, I try to use most of them sparingly.
Most importantly, I follow the recommendations of major health organizations who base their advice on high-quality, peer-reviewed research and the conclusions of scientific experts. The Academy of Nutrition and Dietetics says seed oils can be part of a well-rounded diet. And the American Heart Association says there’s no reason to avoid seed oils–and that they can actually help you enjoy healthy foods like vegetables.
