Are seed oils really toxic?

If you’ve spent any time on the wellness TikTok recently, you may have noticed that there is an abundance of publications claiming that canola oil and other seed oils are unhealthy and should be avoided. There is a lot videos that make bold claims saying that seed oils cause inflammation, or that they are “toxic” or even “poison.”

But is this actually true?

Many of the videos don’t include sources, and some nutrition experts don’t fully agree with all of these fast-spreading claims. To get to the bottom of the seed oil debate, we reached out to leading doctors and registered dietitians.

Read on for everything you need to know about seed oils, including whether you should give them up.

Seed oils are a category of plant-based oils made from the seeds of plants. Some of the most common seed oils are soybean, grapeseed, sunflower, safflower, and canola (also known as canola).

“Seed oils are made by grinding, pressing and heating plant seeds to high temperatures so that the fatty acids they contain are oxidized and their oils can be extracted,” he explained Maddy Pasquariello, registered dietitian. Seed oils are commonly used in packaged foods on grocery store shelves, in commercial food production, and in the restaurant and food service industries.

One of the reasons that seed oils are used in so many different foods is that they often have a mild flavor and aroma.

This question is not as cut and dry as one might expect.

“Seed oils can be a healthy part of the diet, especially if the consumption of these oils is combined with an adequate intake of omega-3 fatty acids, such as those that come from oily fish or walnuts,” said Lauren Manaker, registered dietitian.

At the same time, it’s also true that many foods made with seed oils, such as ultra-processed foods and fried foods, are not good for human health, said Ashley Kitchens, registered dietitian. But that doesn’t necessarily mean that seed oils cause problems. Highly processed foods often contain high amounts of sodium, sugar and refined carbohydrates, which can cause health problems when consumed in excess.

“It would be more beneficial for your health to focus your efforts on reducing your intake of these types of ultra-processed and fried foods rather than focusing solely on seed oils,” Kitchens said.

Seed oils are often heated to high temperatures for deep frying and other purposes when making highly processed foods—and that’s not great for human health. Seed oils that contain large amounts of an omega-6 fatty acid called linoleic acid generate a compound called hydroxynonenal when heated to a high temperature above their smoke point. Ingestion of this compound can lead to health problems such as disturbed energy metabolism and increased oxidative stress.

But that doesn’t mean you can’t heat seed oil when cooking at home.

“The amount you cook with at home is probably much smaller, and you’re unlikely to have poor health simply because it’s one ingredient you use in cooking,” Pasquariello said.

Seed oils contain varying amounts of omega-3 and omega-6 fatty acids, which are polyunsaturated fats considered healthy. The amount of omega-3 and omega-6 fatty acids varies from one seed oil to another. For example, flaxseed oil contains a high amount of omega-3 fatty acids, while sunflower and soybean oils have higher amounts of omega-6 fatty acids, and palm kernel oil contains only trace amounts of omega-3 fatty acids, Kitchens said. The body needs fatty acidsbut it cannot produce them on its own, so they must come from food sources.

While we need omega-6 fatty acids, there are concerns that these fatty acids, when consumed in large amounts, can lead to inflammation, said Christina Tennyson, MD, a board-certified gastroenterologist at Augusta Health.

“Nutrition studies are extremely difficult to conduct and interpret, so I think the jury is still out as far as current research is concerned,” Tennyson said.

“There is some concern about the ratio of omega-6 to omega-3 fatty acids in refined seed oils, with omega-6 fatty acids thought to be pro-inflammatory, but the significance of this is unclear,” said Dr. Linda Shiue , director of culinary and lifestyle medicine at Kaiser Permanente San Francisco.

One thing to keep in mind in the meantime is that you don’t need to include seed oils in your diet just to make sure you’re getting enough of these important fatty acids.

“Whole soybeans, nuts, seeds, fish and eggs are likely to be more beneficial sources of omega-6 fatty acids when looking at their complete nutritional profile, compared to oil consumption alone,” Pasquariello said. “So I would advise people to try adding these alternative dietary sources of fat first if adding extra omega-6 fatty acids is recommended for them.”

Seed oils offer a variety of healthy fats and can be a good substitute for products higher in saturated fat.

“Studies show that Omega-3 rich oils can protect against certain cancers and improves heart health,” Kitchens said.

In addition, omega-6 fatty acids may reduce the risk of cardiovascular disease, according to the American Heart Association. To improve cardiovascular outcomes, cclinical guidelines generally recommend replacing sources of saturated fat—such as butter, coconut oil, palm oil, bacon grease, and sausages—with sources of polyunsaturated fat, such as walnuts, flaxseed, fish, and most seed oils, including canola, soybean, saffron and grape seeds, Pasquariello said.

Does this mean you should go out of your way to include more seed oils in your diet? Probably not.

“Fat is still high in calories—9 calories per gram, compared to 4 calories per gram found in carbohydrates and protein sources—and seed oils are indeed a component of many foods that are less nutritionally dense.” density,” Pasquariello said.

In moderation, seed oils are probably fine to eat, especially if you cook with them at home. You don’t have to avoid them at all costs, as some TikTok videos would have you believe, but you also don’t have to go out of your way to eat more of them. Eating whole foods like walnuts, sunflower seeds, peanut butter, edamame, chia seeds, almonds and hemp seeds is a great way to get fatty acids.

“In the context of a healthy diet consisting mostly of whole plants, seed oils consumed in moderation — the small amounts used in cooking — are unlikely to cause harm,” Shiue said. “I am more concerned about diets high in ultra-processed food and added sugars, both of which have better evidence of causing negative health outcomes and chronic disease.”