Seed oils cause inflammation

The scientific evidence does not support the claim that seed oils cause inflammation, according to nutrition scientists.[7] The concern is based on a misunderstanding of how omega fatty acids work in the body.

The reasoning behind this claim stems from the fact that linoleic acid, an omega-6 fatty acid found in seed oils, can theoretically be converted to arachidonic acid, which is a precursor to pro-inflammatory compounds.[6] However, this conversion is minimal—only about 0.2% of omega-6s is converted to arachidonic acid.[6] A 2017 meta-analysis of randomized controlled trials found that increased dietary intake of linoleic acid does not have a significant effect on blood concentrations of inflammatory markers.[6] Additionally, two systematic reviews of randomized controlled trials demonstrated that higher intake of linoleic acid did not increase or had no effect on inflammatory markers.[3]

The key misunderstanding involves the role of omega-6 fats. While omega-3 fats are more anti-inflammatory than omega-6 fats, this does not mean omega-6 fats are pro-inflammatory.[5] Both omega-6 and omega-3 fats play roles in the body's inflammatory response, which is actually necessary for healing.[5] The real concern should be excessive inflammation from overeating ultra-processed foods, which may contain harmful ingredients like added sugar and high-fructose corn syrup, rather than seed oils themselves.[5]

Notably, some research actually suggests benefits: higher intakes of omega-6 were associated with a 9% reduced risk of dying overall.[2] Additionally, multiple studies show that seed oils can reduce total cholesterol, LDL cholesterol, and triglycerides, and may improve antioxidant activity.[1]