Composition
Seed oils are vegetable oils derived from the seeds, rather than the fruit, of plants. Examples include canola, soybean, corn, sunflower, cottonseed, peanut, rice, safflower, sesame and grapeseed.
The composition of seed oils varies substantially but all primarily include unsaturated fatty acids and are relatively low in saturated fatty acids. Fatty acids are the building blocks of the fat in our bodies and the food we eat. Canola oil has the least saturated fat (7%) of all common edible oils.
The main fatty acid in some seed oils, such as soybean and corn, is the polyunsaturated fatty acid (PUFA) omega-6 linoleic acid. In other seed oils, such as canola, a monounsaturated fatty acid (MUFA) is most prevalent (62%), followed by linoleic acid (19%) and the omega-3 linolenic acid (9%). Humans have a biological requirement for the latter two PUFAs, deemed “essential” because the body cannot produce them on its own.
Expert Recommendations
Seed oils are highly recommended as healthy sources of fat by the Dietary Guidelines for Americans, American Heart Association, Academy of Nutrition and Dietetics and other leading health organizations. These groups specify that non-tropical vegetable oils high in unsaturated fat should replace rich sources of saturated fat, including butter, tallow, lard, palm and coconut oils, and ghee. Canola oil even qualifies for the American Heart Association Heart-Check Food Certification Program.
Since 2010, the Dietary Guidelines for Americans by the U.S. Department of Agriculture and Department of Health and Human Service have recommended limiting saturated fat to less than 10% of total caloric intake. Seed oils help meet this recommendation by replacing sources of saturated fat. Canola oil is consistently recommended as part of healthy dietary patterns.
Scientific Evidence
Clinical and observational studies show that intake of the omega-6 linoleic acid in seed oils does not increase inflammation or oxidative (molecular) stress. In fact, population studies often show that higher intake of this PUFA is associated with reduced, rather than increased, inflammation as well as lower risk of cardiovascular disease, diabetes, cancer and overall mortality. U.S. consumption of linoleic acid accounts for 7-8% of caloric intake, which is in line with dietary recommendations (5–10% of calories).
Significant clinical evidence supports the beneficial effect of replacing saturated fat with unsaturated fat on cardiovascular events and risk factors. Research shows that canola oil-based diets, compared with those high in saturated fat, can reduce total and LDL cholesterol in healthy people and those with high cholesterol, reducing the risk of heart disease. In 2006, the U.S. Food and Drug Administration authorized a qualified health claim on canola oil’s ability to reduce the risk of coronary heart disease when used in place of saturated fat.
Observational and clinical studies show that diets higher in unsaturated fat may help reduce risk of developing and/or managing type 2 diabetes. Canola oil consumption substantially reduces total and “bad” LDL cholesterol levels and improves insulin sensitivity when used in place of saturated fat. It can also help control blood glucose and lower LDL cholesterol in people with type 2 diabetes when included in a low-glycemic index diet.
Resources
News Release: Data Support Health Benefits of Seed Oils High in Unsaturated Fatty Acids 11.19.24
FAQ: Seed Oils Fact and Fiction
USCA Blog: Data Support Health Benefits of Canola and Other Seed Oils High in Unsaturated Fat 10.30.24
Seed Oils & Health: Fact vs. Fiction 3.12.25
Recent Research: Perspective on the Health Effects of Unsaturated Fatty Acids and Commonly Consumced Plant Oils High in Unsaturated Fat, British Journal of Nutrition, 10.30.24
Beneficial Effects of Linoleic Acid on Cardiometabolic Health: an Update, Lipids in Health and Disease, 9.12.24
Butter and Plant-Based Oils Intake and Mortality, JAMA Internal Medicine, 3.6.25