If you’ve been told that seed oils are toxic or that omega-6 fats cause inflammation, you’re not alone. Social media is full of claims that common cooking oils — like soybean, sunflower, safflower and corn oil — are responsible for everything from joint pain to chronic illness. But a new study suggests that concern may be seriously misplaced.
Researchers analyzed blood samples from more than 2,700 adults participating in the long-running Framingham Offspring Study. They measured levels of two key omega-6 fats — linoleic acid and arachidonic acid — and compared them to 10 different markers of inflammation and oxidative stress.
The result? People with higher levels of omega-6 fats had lower levels of multiple inflammatory markers. And none of the markers showed any sign of increased inflammation as omega-6 levels rose.
Published in Nutrients, the study directly challenges the widespread belief that omega-6 fats promote chronic inflammation. Linoleic acid, in particular, is the most common polyunsaturated fat in the American diet and is found in nearly all seed oils. While some critics claim we consume too much of it, this study adds to a growing body of evidence that omega-6 fats may actually help reduce inflammation, not cause it.
“These new data show clearly that people who have the highest levels of (omega-6 fats) in their blood are in a less inflammatory state than people with lower levels,” said lead investigator Dr. William S. Harris, president of the Fatty Acid Research Institute. “These findings contradict a narrative, not previous research findings.”
So what does this mean for your grocery cart?
It means that seed oils like canola, sunflower and soybean oil are not the dietary villains they’re often made out to be. While balance with omega-3 fats from sources like fish, flax or chia is still important, there's no strong evidence that omega-6s are harmful in reasonable amounts. In fact, when used in place of saturated fats, they may even support heart health.
The study was conducted by researchers at the nonprofit Fatty Acid Research Institute using data from the Framingham Offspring Study. It was supported in part by the National Institutes of Health and by the Soy Nutrition Institute Global, with additional support from the United Soybean Board.
Harris, the study’s lead author, is a longtime fatty acid researcher who also founded a commercial lab specializing in omega fat testing.