What are seed oils? The complete list
Seed oils are industrial cooking oils pressed and refined from seeds, usually with high heat and chemical solvents. They are very high in polyunsaturated fat (PUFA), which is unstable when heated and builds up in the body over time.
The 8 seed oils people avoid
- Canola (rapeseed) oil. The most common restaurant oil. Cheap, heavily refined, very high in PUFA.
- Soybean oil. The number-one oil in the American diet, often hidden as "vegetable oil."
- Corn oil. A refined, high-PUFA oil common in frying and processed food.
- Sunflower oil. High in PUFA unless it is a "high-oleic" version, which is more stable.
- Safflower oil. Among the highest-PUFA oils of all.
- Cottonseed oil. A byproduct oil used in frying and shortening.
- Grapeseed oil. Marketed as gourmet, but very high in PUFA.
- Rice bran oil. Refined and high in PUFA; common in Asian fast food.
On a label, watch for "vegetable oil," which is usually soybean or canola, and any oil above that is not olive, avocado, coconut, butter, ghee, or tallow.
Why do people avoid them?
Seed oil intake has risen dramatically over the last century, and the linoleic acid from these oils now makes up far more of our body fat than it used to. When heated for frying they throw off oxidation products that stable fats do not. The case is debated, but a growing number of people choose to minimize them and cook in butter, tallow, coconut, or olive oil instead. See the evidence and the petition.
Next: see the cleanest fast food, the full Seed Oil Index, or check whether a food has seed oils.