5 Myths About Seed Oils You Have to Stop Believing

• Seed oils are often unfairly labeled as “unhealthy,” despite lack of research to support this claim.
• Current research shows that seed oils are not linked with inflammation or poor health, and may actually support good health.
• Rather than demonizing seed oils, it’s wiser to focus on eating a balanced, minimally processed diet.

“Seed oils” is a term that almost no one searched for until 2022. Does that make them new? Not at all. In fact, they’ve been around for decades. The term refers to oils made from the seeds of plants, like sunflower, canola, soybean and grapeseed. Recently, they’ve become a controversial ingredient, with some wellness influencers saying they’re harmful for your health. 

But the science and most nutrition experts don’t support these claims. “Nutritionally, seed oils are sources of unsaturated fats, including omega-6 fatty acids, which are essential for health and play important roles in cell structure, hormone production and brain function,” states Jaclyn London, M.S., RD, CDN. 

Current dietary guidelines recommended eating more unsaturated fat and fewer saturated fats, especially to support heart health. Despite this, unqualified voices online often encourage their followers to swap seed oils for butter, lard and beef tallow—all of which are high in saturated fat. It’s no wonder the conflicting advice can leave you wondering what’s fact and what’s fiction. To set the record straight, we spoke with experts to debunk five common myths about seed oils that you can stop believing.

Myth #1: Seed Oils Are Inflammatory

This myth likely stems from the fact that seed oils are high in linoleic acid, a type of omega-6 polyunsaturated fat. Some have speculated that diets too high in omega-6 fats are linked with chronic, low-grade inflammation. The theory goes that because linoleic acid can be converted into arachidonic acid—a precursor to certain inflammatory molecules—eating foods high in linoleic acid could trigger inflammation.

However, emerging research challenges this idea. Numerous studies have found no association between seed oil consumption and inflammation—and some research suggests these oils may even reduce inflammatory markers.,,, One consideration is that the conversion of linoleic acid to arachidonic acid in the human body is limited, meaning it’s unlikely to cause widespread inflammation. 

Another important factor is the overall omega-6 to omega-3 ratio in the standard American diet, which is often around 20-to-1. This is largely due to the prevalence of omega-6-rich oils in ultra-processed foods. That doesn’t mean that the oils themselves are unhealthy—they’re just widely used in processed products. The real issue is that most people aren’t getting enough omega-3 fats to balance the ratio. In other words, inflammation is influenced more by overall dietary patterns than by the presence of seed oils alone. 

Inflammation isn’t driven by a single nutrient. “The type of oil in which your food is cooked matters a whole lot less than the food itself—and your dietary pattern on the whole,” notes London. Instead of obsessing over which oil to use, she recommends focusing on nutrient-rich vegetables, seafood, pulses, nuts, seeds, lean protein and unsweetened dairy. Then, use a variety of fats and cooking oils sparingly. Together, this forms the foundation of an anti-inflammatory eating pattern.

Myth #2: Seed Oils Are Bad Because They’re GMO

Some seed oils—not all—come from genetically modified plants, since crops like corn, soy and canola are often genetically engineered in the United States. “GMO crops are not bad; rather they are crops modified to increase pest resistance, reducing the need for certain pesticides and insecticides,” points out Amy Brownstein, M.S., RDN. 

The Food and Drug Administration sets strict safety standards for GMO foods and crops grown in the U.S., and research shows that GMO crops are just as safe as non-GMO varieties., If you prefer to avoid GMOs, certified organic oils are made from GMO crops.

Myth #3: Seed Oils Are Bad for You Because They’re an Ultra-Processed Food

There’s a lot of talk about eating fewer ultra-processed foods, especially those high in added sugar, sodium and saturated fat. While emphasizing whole foods is generally beneficial, eliminating all ultra-processed foods without context can lead to cutting out some relatively healthy options. “Yes, they are industrially processed and refined, but they fall into a different category of processed foods,” notes Jacob Smith, M.S. One widely used system, the NOVA classification, actually categorizes seed oils as a processed culinary ingredient, not an ultra-processed food.

“You don’t sit down for a snack or meal of canola oil—you use it inside recipes or as a cooking oil,” he adds. The amount used in cooking is typically small, meaning actual consumption is minimal. What’s more important is the overall context of the foods you eat with these oils. “Seed oils are commonly used in fast food, restaurant meals and packaged or ready-made food items,” says Brownstein. “Other components of these foods, their high energy-density and the portion size likely play a greater role in the negative health effects associated with seed oils.”

Myth #4: Seed Oils Cause Poor Health

Although seed oils are often blamed for various health issues, research consistently shows this isn’t true. “If you want to know if something is causing harm, you look at research on people who are actually consuming the thing,” states Smith. “You can try to say any component of a food item is harmful, but if the research shows they do not cause harm, then they are probably not causing harm,” he says.

Looking at data from actual consumers, seed oils are not linked to poor health outcomes—particularly for heart health. For example, a recent review study found that eating unsaturated fats, including seed oils, was linked with lower total and LDL (“bad”) cholesterol. The review also found some evidence that suggests eating seed oils may lower body weight and improve blood sugar management.  Another study found that consumption of canola oil was even more effective than olive oil at reducing total and LDL cholesterol.

Regarding mortality, a cohort study of roughly 221,000 people found that for every 5 grams per day of soybean or canola oil consumed, there was a 6% and 15% lower risk of premature death, respectively. The study also found that replacing 10 grams per day of butter with plant-based oils—including seed oils—was linked with a 17% lower risk of premature death.

Overall, the evidence suggests that seed oils may support health rather than harm it. How you use it—and how much—matters. “Anything you eliminate from your diet is only as good for your health as what it’s replaced with,” adds London. “Swapping lard for canola oil to sauté vegetables is a step toward better health. Swapping lard for canola oil to deep-fry foods nightly? That’s unlikely to deliver the same benefit.”

Myth #5: Seed Oils Are Rancid and Oxidized

“Oils high in polyunsaturated fat, like seed oils, are more prone to oxidation when exposed to heat, light and air, which can produce potentially harmful compounds,” notes London. “But here’s the context: all fats are susceptible to oxidation—it’s just a question of how quickly.”

That’s why nuts last longer in the freezer and it’s why olive oil should be stored in a cool, dark place. The same applies to any oil: keep it in a dark bottle, away from light and heat, which accelerate oxidation and spoilage. Otherwise, it’s like saying you shouldn’t eat blueberries because they eventually grow mold. What matters is proper storage and consuming foods before their expiration date.

Our Expert Take

Seed oils have become the villain of the nutrition world—but their bad reputation is largely undeserved. “The bigger issue isn’t the seed oils themselves—it’s the types of foods they’re most often found in: ultra-processed packaged foods that are also high in calories from added sugar, saturated fat and sodium, and low in antioxidants, fiber and key minerals we need for health,” says London. 

Smith adds, “Though they have been vilified and painted as the culprit in the case of increasing chronic disease rates, seed oils are so small on the list of concerns that they should not even be considered in the grand scheme of things.” 

When most Americans fall short on fiber, fruit or vegetables—and overconsume added sugar and sodium—fixating on seed oils feels like a classic case of missing the forest for the trees. Plus, research shows these oils aren’t linked to the health pitfalls they’re often blamed for. Rather than demonizing one ingredient, it’s more productive to focus on building balanced, nutrient-rich meals.