Choosing the best oil for cooking can be a confusing task. This is especially true if you follow wellness accounts on social media, where users have been posting heated debates about why home cooks should avoid seed oils. But are these oils as harmful as people say? To find out, we tapped a registered dietitian for an expert explanation and a professional chef to determine when seed oils are appropriate to use.
What Are Seed Oils?
A seed oil is an oil that’s made from the seeds of a plant, says Maddie Pasquariello, MS, RDN, registered dietitian. They’re made by “cleaning, grinding, pressing, and heating plant seeds to high temperatures, so their oils and fatty acids can be extracted,” she explains. The oils are typically refined (purified) before they’re packed and hit the shelves, notes Nathan Lyon, chef, cookbook author, and television personality.
The most commonly used seed oils include the following, according to Lyon:
- Canola (rapeseed) oil
- Sunflower oil
- Sesame seed oil
- Corn oil
- Peanut oil
- Safflower oil
- Soybean oil
Seed Oil Uses
“Seed oils are commonly found in kitchens in restaurants [and] homes, in fast food restaurants for deep-frying, and as an ingredient in many packaged and processed foods,” says Pasquariello. Seed oils are also inexpensive and stable, as they have high smoke points. This means they can withstand high cooking temperatures before they begin to smoke and oxidize, says Lyon. Additionally, many seed oils are neutral in flavor so they can be used with a variety of ingredients.
Why Do Some People Avoid Seed Oils?
Despite their stability and versatility, seed oils have sparked controversy on social media in recent years. According to some users, seed oils are highly inflammatory, toxic, and the direct cause of chronic disease. Seed oils are also demonized due to their high-calorie content, prompting a lot of fear and unhealthy thinking around them, Pasquariello points out.
The Truth About Seed Oils, According to a Dietician
It’s important to remember that social media claims about seed oils are often oversimplified. For seed oils specifically, many of the claims overlook the research behind how seed oils actually function in the body and diet, according to Pasquariello.
Here, Pasquariello briefly breaks down the main claims surrounding seed oils.
Inflammation
According to sources on social media, seed oils can increase inflammation. This likely stems from the fact that seed oils contain linoleic acid, a type of omega-6 fatty acid, that can cause inflammation in the body. “People often [claim] we should be cutting down on omega-6 consumption, when in reality, it’s more about consuming these foods in moderation,” says Pasquariello. It’s also worth focusing on eating more omega-3 fatty acids, rather than worrying about your ratio of omega-6s and omega-3s.
What’s more, the level of inflammation a food can cause is unique to each person, as it depends on many factors. This includes how much of that food you ingest, your specific health at the time, and other food you’re eating, says Pasquariello. Therefore, it’s inaccurate to credit inflammation to the effects of a single food or ingredient.
Toxicity
On social media, people claim that seed oils are “toxic,” but this is a simplified statement. When seed oils are constantly reused, the oils can become rancid and oxidize, causing toxic compounds to form. This is more likely to happen in a fast food restaurant, so there’s a higher risk of exposure if you’re eating fast food regularly. However, when using seed oils in your own kitchen at home, there’s no serious risk of oxidation due to the small amounts used, says Pasquariello.
When to Use Seed Oils
Is it safe to use seed oils at home? Absolutely, says Pasquariello. “When used in moderation as a small percentage of your daily calories [and] cooked or used in recipes following the proper temperature guidelines, seeds oils are safe to eat,” she says. In other words, unless you’re repeatedly deep frying with the same oil or taking shots of seed oil (which is not recommended!), there’s little to worry about, Pasquariello.
With that in mind, seed oils are best used for high-temperature cooking such as deep fat frying and searing meats over high heat, says Lyon. They’re also ideal for salad dressings or marinades where you want a neutral flavor, adds Lyon. If you’re looking for an oil with more depth—when garnishing a dish, for example—you might want to skip the seed oil and use toasted sesame, walnut, or extra-virgin olive oil.
Alternatives to Seed Oils
If you’re looking for a seed oil substitute, consider avocado oil. It’s a “great alternative to seed oil as it has a very high smoke point,” says Lyon.