Seed oils, while often found in ultra-processed foods, are not ‘unhealthy on their own’

Key takeaways:

• Seed oils are often incorrectly tied to health risks like chronic inflammation, according to an expert.
• Evidence suggests that seed oils can lower the risk for diseases like CVD or diabetes and death.

Seed oils, though often found in unhealthy foods, serve an important role in a healthy diet by functioning as a “key source” of fatty acids that can lower chronic disease risk, an expert said.

“It is true that seed oils are often found in ultra-processed foods, but that doesn’t make the oils unhealthy on their own,” Matti Marklund, PhD, MSE, an assistant professor in the department of international health at Johns Hopkins Bloomberg School of Public Health, explained during a press briefing. “What matters is the overall nutrient quality and the degree of processing in foods.”

Social media has fueled misconceptions about seed oils, with some influencers claiming the oils can cause chronic inflammation, obesity, brain fog and toxicity, according to Mass General Brigham. These misconceptions often center on the refining process and high levels of omega-6 fatty acids, Marklund said.

He noted seed oils are an “important source of healthy fats, especially linolic acid, which is an essential omega-6 fatty acid that the body cannot make on its own and must get from food.”

Such nutrients can have a beneficial effect on various aspects of health. For example, “linoleic acid is the most abundant polyunsaturated fat in most peoples’ diets, and scientific studies consistently show that higher intake is linked to a lower risk of chronic diseases, including heart disease, stroke and type 2 diabetes,” Marklund said.

He said that concerns over balancing omega-3 and omega-6 fatty acid intake, and reducing the latter, are “not supported by current evidence” and that both fats “have complementary roles in the body.”

“There is no credible evidence that seed oils or linoleic acid promote inflammation in humans,” he said. “In fact, research shows the opposite. Higher intake is associated with better heart health and lower risk of premature death.”

“Replacing saturated fats like butter, lard or tallow with polyunsaturated fats from seed oils can improve cholesterol and reduce cardiovascular risk — a change supported by decades of nutrition science,” he added.

Thus, there is no strong scientific basis for policies that would restrict access to seed oils, Marklund said.

“Doing so may mislead consumers and shift attention away from more important dietary improvements like reducing intake of salt or added sugars,” he added.

Marklund encouraged primary care providers to educate their patients on seed oils.

“We should encourage patients to use seed oils like soybean, canola or sunflower oil instead of using butter or lard, and that is a simple, evidence-based way to support heart health,” he said.

For patients who want to especially increase their intake of linoleic acid, “soybean oil would be a great choice,” Marklund added. “Canola oil also provides omega-3 fatty acids, so that could also be a great choice. Those are my two favorites, but you can probably use a wide variety of seed oils.”