Seed Oils: Setting the Record Straight

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In the last year, several major restaurants and health food brands have pivoted away from using seed oils and are instead turning to butter and beef tallow as “natural” alternatives.

This shift is largely in response to many in the Make America Healthy Again (MAHA) movement, led by HHS Secretary Robert F. Kennedy Jr., claiming that seed oils contribute to inflammation and chronic disease. MedPage Today had experts weigh in on whether this war on popular cooking oils has any seed of truth.

Until a few years ago, the term “seed oils” was barely used. Seed oil critics specifically target what they call the “hateful eight”: canola, corn, cottonseed, grapeseed, rice bran, safflower, soybean, and sunflower.

Marian Glick-Bauer, MS, RD, manager of nutrition and dietetics at Long Island Jewish Medical Center in New York City, said that seed oils are simply a category of vegetable oil and that different seed oils are not the same in terms of their content. Some seed oils, like flax seed oil and walnut oil, are higher in omega-3 fatty acids and polyunsaturated fats, which have many proven health benefits and are also commonly found in avocados, chia seeds, and fatty fish.

Others, like corn oil, have less omega-3 and more omega-6. In fact, the ratio of omega-6 versus omega-3 fatty acids found in seed oil is a major source of controversy.

“People tend to say that omega-6 is the ‘bad’ fatty acid, and that’s not really fair — our body needs both,” Glick-Bauer told MedPage Today. The body can’t make either on its own, so people need to get both from food.

Matti Marklund, PhD, MSE, assistant professor in the department of international health at the Johns Hopkins Bloomberg School of Public Health in Baltimore, concurred while speaking at a press briefing about seed oil misinformation. Scientific evidence, he said, doesn’t support the idea that people should cut back on omega-6 just because they generally need more omega-3 in their diet.

“Omega-3 and omega-6 fats have complementary roles in the body,” Marklund said, and seed oils are an “important source of healthy fats, especially linoleic acid, which is an essential omega-6 fatty acid that the body cannot make on its own and must get from food.”

The balance of omega-3 and omega-6 also varies in other cooking fats. For animal fats, the balance can differ based on how the animal was fed. Animals that eat more grass and vegetation will have higher omega-3 in both meat and fat than those fed mostly corn, but grass-fed products will also be more expensive.

Beyond nutritional value, seed oils are often affordable, shelf stable, and have a neutral flavor making them versatile for cooking. Glick-Bauer noted that for many patients, fretting over what cooking fat they use is not a luxury they can afford, as their budgets may only allow for canola or corn oil. And many people live in areas where seed oils are the most readily available options. If they’re cooking a nutritious meal with a little corn oil, they shouldn’t be made anxious about that, and Glick-Bauer encouraged healthcare providers to be mindful of this when speaking to patients.

On alleged ties between seed oil consumption and inflammation, Glick-Bauer said that many people focus on the wrong thing. If someone is worried about reducing chronic inflammation, the solution is to eat a balanced diet with lots of fruits, vegetables, fiber, and healthy fats, and to reduce reliance on packaged and processed goods.

“We want to focus on the whole diet and not the latest fad on social media,” she said.

Marklund noted that ultraprocessed foods often contain seed oils, but the seed oils are not what make those foods unhealthy. “What matters is more the overall nutrient quality and the degree of processing of food,” he said.

“Despite widespread claims online, there is no credible evidence that seed oils or linoleic acid promote inflammation in humans,” Marklund said. “In fact, research shows the opposite: higher intake is associated with better heart health and lower risk of premature death.”

While some in the MAHA movement have encouraged replacing seed oils with butter or tallow, the opposite may have more benefits, Marklund said. Diets high in saturated fats are linked to heart disease and high cholesterol.

Glick-Bauer noted that as a whole, the conversation about seed oils needs more nuance and multiple sources of fat can be part of a healthy diet.

“There’s a real tendency, especially on social media or with health influencers, to suddenly focus on one very narrow type of food to vilify … and say all of the problems that we face in the Western diet can be attributed to this one thing,” Glick-Bauer said, and right now, that trendy thing is seed oils. “I think it’s really a huge oversimplification.”

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