Are Seed Oils and Vegetable Oils Bad for You?

Text Callout : Key Takeaways – Seed Oils

The “hateful eight” might be the band of violent travelers from a Quentin Tarantino movie, but they’re also an octet of seed oils that a growing number of people, from influencers to politicians, have deemed toxic:

Seed oils are a type of vegetable oil. Seed oils differ from other plant-based oils, such as olive and avocado oils, in which the fats are squeezed out of the fruit or pulp of plants. Collectively, these two categories are referred to as vegetable oils.

Robert F. Kennedy Jr., the United States Secretary of Health and Human Services, has singled out seed oils as part of the “Make America Healthy Again” or MAHA agenda, calling them “one of the most unhealthy ingredients that we have in foods.”

Fast-casual restaurants are boasting about their seed oil-free menus, including Sweetgreen, True Food Kitchen and Steak ‘n Shake, where Kennedy sat down in front of cameras to praise the restaurant’s new french fries cooked in beef tallow. A growing array of food products are also touting their status as seed oil-free, including Beefy’s Own and Vandy Crisps potato chips fried in beef tallow.

Experts say scientific evidence doesn’t support the claims of toxicity of seed oils, so we’ve unpacked the good and the bad about these vegetable oils made from the seeds of a plant, as well as other vegetable oils.

Raw HTML : Diets Table – Best Heart-Healthy Diets

What Are Seed Oils and Vegetable Oils?

Vegetable oils, such as olive oil and coconut oil, are edible oils extracted from plants or seeds. Seeds oils, such as the so-called “hateful eight,” are the oils that specifically come from plant seeds.

“You take the seed, and when you squish it, oils come out,” explains Jeanne Freeland-Graves, the Bess Heflin Centennial Professor and division head of nutritional sciences at the University of Texas at Austin. “We’ve been doing this for centuries.”

This process of extracting oil is known as “cold-pressing,” meaning the oil is derived without heat. Cold-pressed oils may be higher in nutrients, but they have a shorter shelf-life, take longer to produce and usually result in smaller quantities.

These cold-pressed oils, Freeland-Graves notes, may also be cloudier. To refine the oil and reduce the cloudiness, manufacturers sometimes use heat, which oxidizes, or breaks down the oil. They might also use other chemicals or pressure to extract and purify the oil.

The heating process and the fatty composition of these oils are what bring in the naysayers.

Are Seed Oils and Vegetable Oils Bad for You?

No. But critics point to the high levels of omega-6 fatty acids in seed oils, claiming they cause inflammation and chronic disease when consumed in excess. Yet that argument is flawed in numerous ways, says Christopher Gardner, the director of nutrition studies at the Stanford Prevention Research Center, who has studied the health effects of dietary changes, including oils and fats, for more than three decades.

While it’s true that seed oils are high in omega-6 fatty acids, that’s not a bad thing. In the past, studies suggested that excess omega-6 causes inflammation, says Dr. Marijane Hynes, clinical professor of medicine at the George Washington University School of Medicine and Health Sciences in Washington, D.C. Yet, much of those conclusions were based on small or animal and lab-based studies with little statistical significance or reliability.

Those effects haven’t been shown in humans. In fact, a large meta-analysis of 30 randomized controlled studies found that eating more omega-6 didn’t change people’s inflammatory markers.

Omega-6 gets unfairly demonized because these fatty acids play a smaller role in reducing cardiovascular risk compared to omega-3s, polyunsaturated fats also found in some plant oils, as well as fish. That doesn’t mean omega-6 is bad for you, it’s just that omega-3s are more effective at reducing cardiovascular risk and providing anti-inflammatory benefits.

“Research has suggested that omega-3 fatty acids may help to decrease the risk of blood clots, improve blood lipid levels, decrease blood pressure, protect against irregular heartbeats and suppress inflammation, thereby supporting brain health and decreasing the risk of some cancers,” says Nancy Farrell, a Fredericksburg, Virginia-based registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics.

Farrell also says we need to strike a better balance between our intakes of omega-3 and omega-6. The typical American diet is much higher in omega-6 fatty acids than omega-3s, but research on the optimal ratio of the two remains unclear.

Instead of necessarily reducing omega-6 intake, experts say we should focus on increasing omega-3 through foods like salmon and other fatty fish, fish oil, flaxseeds, chia seeds and walnuts.

Omega-6s may play a smaller role than omega-3s in protecting heart health, but they can still lower LDL cholesterol, which is why the American Heart Association supports the inclusion of omega-6 fatty acids as part of a healthy diet.

Potential Benefits of Seed Oils

Seed oils don’t deserve their seedy reputation, as they offer multiple benefits, especially when you use them in place of saturated fats in your diet. Research, however, suggests that the linoleic acid and arachidonic acid in seed oils may actually have some beneficial effects.

Linoleic acid, the primary omega-6 in seed oil, has been extensively studied with results suggesting a protective role against heart disease. An analysis of 30 studies found that intakes of linoleic acid was associated with a lower risk of cardiovascular events, including death and mortality.

“Linoleic acid is important in supporting healthy blood cholesterol levels,” Farrell explains, adding that omega-6 fatty acids can “help to maintain bone health, improve skin – eczema or psoriasis, for example – and hair health, regulate metabolism and support a healthy reproductive system.”

A new analysis in Nutrition Today summarizes the health benefits of seed oils and linoleic acid, including the lower risk of heart disease, and combats claims that the processing of seed oils causes negative health effects.

A comprehensive research review identifies the health and scientific organizations that recommend the use of omega-6 vegetable oils, including seed oils, as part of a healthful dietary pattern, and concludes that these vegetable oils should be consumed instead of sources of saturated fat, including beef tallow, butter, lard, palm and coconut oils

The Dietary Guidelines for Americans recommends vegetable oil as a nutrient-dense alternative to butter, and lists the total recommended amount of oil consumed per day as 27 grams, which is equivalent to approximately 2 tablespoons per day on a 2,000-calorie diet.

Seed Oils in Processed Foods

Seed oils have been popular for cooking because of their neutral taste, affordability and relatively high smoke points. Margarine, salad dressings and mayonnaise are also often made with seed oils.

Although a dominant source of seed oils is the highly processed foods that have become more prevalent in our diets, experts agree that the seed oils they contain is not the problem. The issue is the calorie-density of these ultra-processed foods that often contain high amounts of added sugar, refined grains and excess sodium, such as:

Gardner says if the seed oils were removed from these foods and replaced with beef tallow, olive oil or avocado oil, that it wouldn’t make a big impact.

“They would still be ultra-processed foods and still be unhealthy,” he says.

Smoke Points and Cooking Methods of Different Oils

Some oils that can handle higher cooking temperatures include safflower, sesame, olive and avocado oil. But a good rule of thumb to follow is to never reuse cooking oil.

When you start heating oil, PUFAs can create harmful chemicals, such as hydroxides and aldehydes, which experts have linked to inflammation.

Reheating these oils, when they continue to break down, can be a health concern because this process produces fumes and compounds that can be carcinogenic. Carcinogens are substances and compounds that have been shown to cause cancer by affecting both cells and the DNA within cells.

Restaurants tend to be guilty of reheating oil.

“You should never reheat oils. You’re supposed to use them once and then throw them away,” Freeland-Graves explains. “But (in the) food industry, they can’t afford to do that. Good restaurants will change their oils and discard them, but that’s expensive.”

Seed Oils vs. Beef Tallow

Is this a good thing to have restaurants and food manufacturers dump seed oils for beef tallow? The move would likely have negative public health consequences.

Beef tallow is rendered from the fat around the organs of cows. It’s high in saturated fat (6 grams per tablespoon) and negligible in nutrients, even the grass-fed versions. Some advocates claim beef tallow is healthier because it’s more natural and blame seed oils for a wide range of health problems.

However, the scientific consensus is that there is no clear evidence seed oils are harmful to health, and switching to animal-based alternatives like beef tallow is likely worse.

Decades of research have linked saturated fat (in beef tallow, lard and butter) to an increased risk of heart disease, while vegetable oils, including seed oils, have been shown to protect heart health.

That conclusion was echoed in a new study that found a higher intake of plant-based oils, especially olive, canola and soybean oils, to be associated with a lower risk of premature death from all causes. Researchers estimated that if people replaced 10 grams of butter per day (about 1 tablespoon) with the same amount of plant oils, they would be 17% less likely to die from any cause, including cardiovascular disease and cancer.

Previous studies have found that people who switched from using mostly saturated fat in their diets to eating more unsaturated fats saw their LDL or “bad” cholesterol levels decrease.

Few topics in the world of nutrition have this much evidence behind the benefits of using vegetables oils instead of animal fats, says Gardner.

Gardner has also served as chair of the American Heart Association’s Nutrition Committee and was a member of 2025 Dietary Guidelines Advisory Committee, which recommends keeping saturated fats to 10% of daily calories. This translates to 22 grams of saturated fat per day. The American Heart Association recommends even less, at 13 grams daily. For context, a serving of the large fries at Steak ‘n Shake contains 16 grams of saturated fat.

Cooking and Storing Oils at Home

The type of oil that’s best to use at home depends on how you plan to use it. Extra-virgin olive oil, a flagship of the Mediterranean diet, has the best heart-healthy nutrient profile and a distinctive taste for salad dressings, dips, finishing a dish or lower-heat cooking such as sauteing vegetables.

Other oils with a higher smoke point, including avocado, peanut, safflower, soybean and light or refined olive oil, can handle high-heat cooking temperatures for searing, stir-frying and deep-frying.

Better yet, skip the frying and try air-frying instead. The Dietary Guidelines for Americans recommends limiting liquid plant oils to about 2 tablespoons a day.

When you are cooking with oils, keep these tips in mind:

Copyright 2025 U.S. News & World Report