Are seed oils healthy or potentially harmful? It's complicated. A dietitian explains why.

On Reddit, the “Stop Eating Seed Oils” community has 42,000 members. On Facebook, the private group “Seed Oil-free snacks and foods” has more than 150,000 members. On TikTok and X, influencers are breaking down nutrition labels and sharing their "hot takes” and warnings about seed oils. There’s even an app that helps people find restaurants without seed oils. The buzz and backlash over seed oils is overwhelming — but is it warranted?

The answer is a bit complicated. Here’s what you need to know about seed oils so you can make the best decision for your own health.

What are seed oils?

Seed oils are exactly what the name implies — oils that are extracted from the seeds of various plants — and include sunflower, canola, soy, safflower, flaxseed, rice bran and sesame oils. These oils are sources of polyunsaturated fats, including omega-6 fatty acids, or essential fats that play an important role in brain function and normal growth and development. Some research suggests omega-6 fatty acids also help support heart health and skin health. However, omega-6s have also been in the spotlight for potentially contributing to inflammation when consumed in excess.

Seed oils are commonly used in dressings, marinades and many ultra-processed foods because of their mild flavor and high smoke point. This makes them a popular choice in commercial kitchens and households alike.

How do seed oils impact health?

The relationship between seed oils and health is complex, despite what some health influencers may tell you. Omega-6 fatty acids can help support overall health in various ways — but there’s one important caveat: The ratio of omega-3 to omega-6 in our diets plays a crucial role in health outcomes, and many Americans who follow a typical Western diet are eating too many omega-6 fatty acids while eating too few omega-3s. A diet too high in omega-6s with insufficient omega-3s may lead to an imbalance that can contribute to inflammation and related health issues. So it’s not necessarily the omega-6 fatty acids found in the seed oil that are the concern. Instead, it’s the quantity of omega-6 fatty acids people consume without balancing it with enough omega-3 fatty acids.

The American Heart Association has weighed in on this, stating that seed oils are not inherently harmful. It emphasizes the importance of replacing saturated fats — found in meat and dairy products — with polyunsaturated and monounsaturated fats, which can be found in seed oils. This shift may help lower cholesterol levels and reduce the risk of heart disease, highlighting the potential health benefits of these oils when consumed in moderation.

The negative perception of seed oils may be more about the foods they're commonly found in rather than the oils themselves. Many ultra-processed and fast foods contain seed oils, but these foods can also be high in unhealthy fats, sugars and sodium. In these cases, it’s usually the food item that’s unhealthy — not the seed oil specifically.

How seed oils are processed matters

One thing to consider when choosing your seed oil is how it’s produced. There are different methods used to make seed oils: cold press (mechanically pressing seeds at low temperatures to extract the oil without any heat); expeller press (seeds are mechanically squeezed at higher temperatures, producing more oil but potentially reducing some of the nutrients, thanks to the heat involved) and solvent extraction (seeds are treated with solvents like hexane to extract the maximum amount of oil; this method often requires further processing to remove the solvent residues and refine the oil).

With solvent-extracted seed oils that use hexane to produce more oil, there are concerns about the potential residue of the solvent in the final product and its environmental impact — although more evidence suggests that the low amount of hexane found in these oils does not pose a health threat to humans. Many manufacturers ensure that hexane is removed during refining, leaving negligible amounts in the products. People who are more comfortable consuming a more natural option that doesn’t lean on hexane can instead seek out oils labeled as "expeller-pressed" or "cold-pressed," which use mechanical methods instead of chemical solvents to extract oil.

Should you avoid seed oils?

For most people, using seed oils in moderation won’t pose significant health risks, especially when balanced with a diet rich in omega-3s from sources like fish, flaxseeds and walnuts. (The Mediterranean diet is a good example to follow.)

Cooking with seed oils can be perfectly safe. However, it’s important to avoid overheating oils beyond their smoke point to prevent the formation of potentially harmful compounds. (You can find handy smoke point charts online.)

When choosing an oil, variety is likely the healthiest approach. Use olive oil, avocado oil and other plant-based oils alongside seed oils to benefit from a range of nutrients. And limit ultra-processed foods that tend to be made with seed oils, like deep-fried foods, shelf-stable pastries and fast food, to avoid exposure to excessive quantities of unhealthy fats, sodium and added sugar. The majority of ultra-processed foods, including potato chips and cookies, contain one or more forms of industrially processed seed oils.

Bottom line

Seed oils don't deserve the bad rap they’ve been receiving. Looking at the big picture and understanding the benefits, limitations and proper uses of seed oils can lead to more informed decisions about food — and a less stressful eating experience.

Lauren Manaker is a dietitian and author.