5 Myths About Seed Oils You Have to Stop Believing

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

But science and most nutrition experts do not support these claims. “Nutritionally speaking, seed oils are sources of unsaturated fats, including omega-6 fatty acids, which are essential for health and play important roles in cellular structure, hormone production and brain function,” it says Jaclyn London, MS, RD, CDN.

Current dietary guidelines recommend consuming more unsaturated fats and less saturated fats, particularly to support heart health. Still, unqualified voices online often encourage their followers to replace seed oils with butter, lard, and suet—all high in saturated fat. It’s no wonder the conflicting advice can leave you wondering what is fact and what is fiction. To set the record straight, we spoke to experts to debunk five common seed oil myths that you can no longer believe.

Myth #1: Seed oils are inflammatory

This myth is likely based on the fact that seed oils have high levels of linoleic acid, a type of omega-6 polyunsaturated fatty acids. Some have speculated that diets too high in omega-6 fats are linked to chronic, low-grade inflammation. The theory is that eating foods high in linoleic acid can trigger inflammation because linoleic acid can be converted into arachidonic acid – a precursor to certain inflammatory molecules.

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

Another important factor is the overall ratio of omega-6 to omega-3 in the standard American diet, which is often around 20 to 1. This is largely due to the proliferation of omega-6-rich oils in highly processed foods. That doesn’t mean the oils themselves are unhealthy – they’re just commonly used in processed products. The real problem is that most people don’t consume enough omega-3 fats to balance the ratio. In other words, inflammation is more influenced by general dietary habits than by the presence of seed oils alone.

Inflammation is not caused by a single nutrient. “The type of oil your food is cooked in is much less important than the food itself – and your overall dietary pattern,” notes London. Instead of worrying about which oil to use, she recommends focusing on nutrient-dense vegetables, seafood, legumes, nuts, seeds, lean proteins and unsweetened dairy products. Then use various fats and cooking oils sparingly. Taken together, this forms the basis for anti-inflammatory nutritional behavior.

Myth #2: Seed oils are bad because they are genetically modified

Some seed oils – not all – come from genetically modified plants, as crops such as corn, soy and canola are commonly genetically modified in the United States. “GMO crops are not bad; rather, they are crops that have been modified to increase pest resistance and reduce the need for certain pesticides and insecticides,” emphasizes Amy Brownstein, MS, RDN.

The Food and Drug Administration sets strict safety standards for GMO foods and crops grown in the United States, 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 plants.

Myth #3: Seed oils are bad for you because they are a highly processed food

There’s a lot of talk about eating fewer highly processed foods, especially those high in sugar, sodium and saturated fat. While emphasizing whole foods is generally beneficial, eliminating all highly processed foods without context can result in leaving out some relatively healthy options. “Yes, they are processed and refined, but they fall into a different category of processed foods,” notes Jacob Smith, MS. A widely used system, the NOVA classification, actually categorizes seed oils as a processed culinary ingredient rather than a highly processed food.

“You don’t sit down for a snack or meal with canola oil – you use it in recipes or as a cooking oil,” he adds. The amount used in cooking is usually small, meaning actual consumption is minimal. More important is the overall context of the foods you eat with these oils. “Seed oils are commonly used in fast food, restaurant fare, and packaged or prepared foods,” says Brownstein. “Other components of these foods, their high energy density, and portion size likely play a larger role in the negative health effects of seed oils.”

Myth #4: Seed oils are bad for your health

Although seed oils are often blamed for various health problems, research continues to show that this is not true. “If you want to know whether something causes harm, look at research on people who actually consume the thing,” Smith explains. “You can try to say that every component of a food is harmful, but if the research shows it doesn’t cause harm, then it probably doesn’t cause harm,” he says.

Looking at data from actual consumers, seed oils are not associated with negative health effects – especially heart health. For example, a recent review study found that consumption of unsaturated fats, including seed oils, is associated with lower total and LDL (“bad”) cholesterol. The review also found some evidence that consuming seed oils can reduce body weight and improve blood sugar control. Another study found that consuming canola oil was even more effective at lowering total and LDL cholesterol than olive oil.

In terms of mortality, a cohort study of about 221,000 people found that for every 5 grams of soy or canola oil per day, there was a 6% and 15% lower risk of premature death, respectively. The study also found that replacing 10 grams of butter per day with vegetable oils – including seed oils – was associated with a 17% lower risk of premature death.

Overall, the evidence suggests that seed oils may support rather than harm health. How you use it – and how much – is important. “Anything you remove from your diet is only as good for your health as what it is replaced with,” adds London. “Replacing lard with canola oil to fry vegetables is a step toward better health. Replacing lard with canola oil to fry foods every night? That probably won’t provide the same benefit.”

Myth #5: Seed oils are rancid and oxidized

“Oils high in polyunsaturated fatty acids, such as seed oils, are more susceptible 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 – the only question is how quickly.”

This is why nuts last longer in the freezer and olive oil should be stored in a cool, dark place. The same goes for any oil: store it in a dark bottle, away from light and heat, as these accelerate oxidation and spoilage. Otherwise it would be like saying you shouldn’t eat blueberries because they will eventually mold. It is important to store food correctly and consume it before its expiration date.

Our expert opinion

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

Smith adds, “Although seed oils are vilified and portrayed as a culprit in rising chronic disease rates, they are so low on the list of concerns that they should largely be ignored.”

When most Americans lack fiber, fruits, or vegetables—and consume too much sugar and sodium—the fixation on seed oils feels like a classic case of missing the forest for the trees. Research also shows that these oils are not associated with the health hazards for which they are often blamed. Instead of demonizing an ingredient, it’s more productive to focus on creating balanced, nutrient-dense meals.