The Truth About Seed Oils: Should You Stop Using Them?
You’ve probably seen the social media posts telling you to toss your canola oil. But is the concern justified? A Sky Lakes registered dietitian sets the record straight.
What Are Seed Oils and Why Are They Controversial?
Seed oils are pressed from the seeds of plants, such as sunflower, soybean, cottonseed, corn, and others. Not everything lumped into this group is a true seed oil; rice bran oil comes from the outer layer of rice grains, and canola is nutritionally closer to olive oil than to the rest.
For decades, health experts recommended them as a heart-healthy swap for butter and other saturated fats. But in recent years, social media has been flooded with claims that seed oils cause inflammation, heart disease, and worse.
The inflammation argument is the one Sky Lakes Nutrition Coordinator Jennifer Newton, RD, MPH, hears most often, and it doesn’t quite jibe with reality.
“The theory doesn’t match up with what’s actually happening in our system,” Newton explains. She says the concern comes from omega-6 fatty acids, which are abundant in seed oils. Omega-6s can act as building blocks for chemicals that trigger inflammation. However, your body tightly regulates how much of that conversion actually happens. Only a small amount turns into the compounds that cause inflammation.
What Science Says
The research on seed oils is consistent: Omega-6 is a type of fat your body needs but can’t produce on its own, and it helps reduce bad (LDL) cholesterol, lowering your risk of heart disease and stroke.
Newton points out that people who use plant-based oils instead of butter do see positive results. High plant oil intake is associated with a 16% lower risk of death from any cause, while high butter intake is linked to a 15% higher risk of cancer and cardiovascular death.
A 2025 study analyzing blood markers from nearly 1,900 people found that higher linoleic acid levels (the main omega-6 fat in seed oils) were linked to lower inflammation, better heart and metabolic health, and a lower risk of cardiovascular disease and type 2 diabetes — the opposite of what seed-oil critics claim.
The Real Problem May Be Ultra-Processed Foods
Newton flags a bigger issue. “We need to look deeper into where our omega-6s are coming from,” she says.
A big chunk of the omega-6s in the American diet comes from ultra-processed foods, which also bring added sugar, excess sodium, saturated fat, and long ingredient lists. The seed oils used in industrial food processing are also more refined than what you buy at the grocery store.
So if you’re concerned about seed oils, the better move is to check your snack cabinet, not your cooking oil.
Which Oils Should You Use at Home?
Newton’s everyday picks are olive oil and canola oil. Olive oil works well for salad dressings and quick sautés, while canola has a neutral flavor, tolerates slightly higher heat, and costs less — a solid pick for baking. Sesame oil is great for stir-fries when you want that distinct flavor.
How to Spot Misinformation
If you see a seed oil claim online, ask yourself: Is this from someone trying to sell something, or from a reputable organization? Newton trusts the American Heart Association, Harvard School of Public Health, and the Academy of Nutrition and Dietetics for solid, evidence-based guidance.
“It’s OK to cook with seed oils at home,” Newton says. “If you want to make a change, start looking at the foods that you’re bringing home in a box or in a package.”
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