Are Seed Oils Toxic?

Welcome back, Wildcat! This week we are covering a nutrition topic- seed oils!

There has been a lot of media attention on seed oils recently, with negative claims about inflammation and toxicity. But are these claims true? Let’s find out.

Seed oils are extracted from the seeds of plants and include canola, sunflower, corn, and sesame oils. Seed oils contain mostly monounsaturated fats, particularly omega-6 fatty acids. There are two main omega-6 fatty acids, linoleic and arachidonic acid. In addition to cooking oils, omega-6 fatty acids can be found in nuts, seeds, eggs, meat, and soybeans. Omega-6 fatty acids are considered essential fatty acids because our bodies cannot build them, so we need to get them from the food we eat. The typical American diet includes many omega-6 fatty acids.

There are claims that consuming too much linoleic acid, an omega 6 found in seed oils, causes inflammation which is thought to lead to other chronic diseases. However, there is not sufficient research to suggest that this is true. In fact, there are several large studies that suggest that consuming omega 6 fatty acids, like those found in seed oils, can help lower cholesterol and reduce the risk for heart disease. This is because omega 6 fatty acids are part of a larger family of monounsaturated fats, which help increase HDL, our “good” cholesterol, and lower LDL, our “bad” cholesterol. According to the American Heart Association, getting at least 5 to 10 percent of your daily calories from omega-6 fats reduces your risk for heart disease.

Another claim against seed oils is that they have toxic byproducts caused from their manufacturing process. Manufacturers use heat and solvents, such as hexane, to extract oil from the seeds. There are claims that this process introduces unstable molecules, which can turn the polyunsaturated fats into harmful trans fats. However, seed oils are only heated for a short period of time, so the amount of trans fats that may occur are minimal, even less than butter and milk. There is more research needed in more diverse populations on seed oils to determine how their manufacturing may affect their nutritional and structural value.

The Academy of Nutrition and Dietetics recommends consuming more monounsaturated fats like omega-6s and polyunsaturated fats like omega 3s and limiting saturated fats found in butter, coconut oil, lard, whole milk, cheese, and meats to promote health and prevent heart disease. Most of all, it is important to increase the variety of fats we consume by eating a variety of different foods. This is the best way to ensure we are getting all the fats that we need in our diet. If you have more questions about seed oils talk to a registered dietitian or your regular provider for more information! See you next time Wildcat!


Omega-6 Fatty Acids and Risk for Cardiovascular Disease. (2022). Circulation. Retrieved from 

Marklund, M., Wu, J., Imamura, F., Del Gobbo, L., Fretts, A., & de Goede, J. et al. (2019). Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality. Circulation, 139(21), 2422-2436. doi: 10.1161/circulationaha.118.038908 

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Choose Healthy Fats. (2019). Retrieved 7 October 2022, from 

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