By Adrianna Rodriguez, TX State University Intern

We have all heard the argument that seed oils are inflammatory and that we shouldn’t consume them because they’re bad for our health, but is that really true? Let’s dive into what research shows and discover the truth about seed oils.

Some of the common seed oils we use are canola, sunflower, corn, soybean, and grapeseed. Seed oils are a subset of vegetable oils commonly used in cooking. They may also be found as ingredients in many processed foods, like fried foods and popular snack foods.

Seed oils are rich in omega-6 fatty acids, a crucial nutrient our bodies can’t produce on their own. But what about omega-3 fatty acids? These are equally important, just not as prevalent in most seed oils. Some seed oils high in both omega 3 and omega 6 are canola and soybean.

Two of the main omega-6 fatty acids are Linoleic acid (LA) and Arachidonic acid (AA). Linoleic acid is generally found in oils, whereas arachidonic acid is found in animal products or will eventually be synthesized from sufficient linoleic acid intake. The main omega-3 fatty acids are Alpha-linolenic acid (ALA), Eicosapentaenoic acid (EPA), and Docosahexaenoic acid (DHA). ALA is generally found in seed oils, and EPA and DHA are usually found in fish.  ALA can be converted to DHA, but at a low rate, so obtaining enough is important if you only eat plant sources. Sources of DHA and EPA, like fish, could contain enough ALA if those sources eat a diet of ALA rich foods.

Balancing omega-3 and omega-6 fatty acids is important for our health. We still need omega-6 fatty acids in our diet, just in moderation. Omega-6 is a type of polyunsaturated fat and is great for heart health and lowering our LDL cholesterol, but most people get a ratio upwards of 20:1 of omega-6 to omega-3. This is exceptionally high compared to the ideal 1:1 ratio. Omega-3 fatty acids are also polyunsaturated fats that are good for heart health and inflammation reduction. Most people do not get enough omega-3 in their diet.

Now that we understand what seed oils are composed of, let’s break down some reasons why many think seed oils are bad for us. Some think seed oils are harmful and inflammatory due to their omega-6 content. Again, omega-6 fatty acids are needed in some amounts because they are essential, but we need to balance out the omega-6 with the omega-3.We also see a lot of seed oils in many commercial processed products that are also high in saturated fats, sodium, and sugar. Therefore, we should look at the full picture of what we get in our diet and not assume it’s one nutrient.

Another reason people believe they are bad is due to the use of hexane to extract seed oils during processing. Hexane is an ideal solvent for seed oils, specifically because it is non-polar and will not mix well with the polar nature of seed oils at high heat. Therefore, hexane can be removed more easily than another type of solvent. Some believe that vast amounts of hexane remain in the seed oils, but distillation removes almost all of the hexane and only leaves trace amounts. Hexane inhalation in different work environments is more likely to cause problems than small amounts through ingestion of seed oils.

To summarize, seed oils can be part of a healthy diet and, in fact, can be good for our health as long as we are aware of how much we are taking in. Based on the research, inflammation and hexane content in seed oils are not of concern. We need to focus less on those who are fear-mongering foods and start focusing on listening to the nutrition professionals and what the research shows.

References

Djuricic I, Calder PC. Beneficial Outcomes of Omega-6 and Omega-3 Polyunsaturated Fatty Acids on Human Health: An Update for 2021. Nutrients. 2021;13(7):2421. Published 2021 Jul 15. doi:10.3390/nu13072421

DiNicolantonio JJ, O’Keefe J. The Importance of Maintaining a Low Omega-6/Omega-3 Ratio for Reducing the Risk of Autoimmune Diseases, Asthma, and Allergies. Mo Med. 2021;118(5):453-459.

Understanding Hexane Extraction of Vegetable Oils. Anderson International Corp. July 31,2023. Accessed June 6, 2024. https://www.andersonintl.com/understanding-hexane-extraction-of-vegetable-oils/

Hexane. Environmental Protection Agency. Accessed June 6, 2024. https://www.epa.gov/sites/default/files/2016-09/documents/hexane.pdf