General Nutrition

Are seed oils bad for your health? A Registered Dietitian explains

June 13, 2024

Written by Chandana (Chandy) Balasubramanian

Medically reviewed by Rita Faycurry, RD

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Key Points

  • Seed oils like canola oil and sunflower oil contain essential fatty acids needed in our diet.
  • However, there is a lot of online chatter about whether seed oils are toxic.
  • The real answer to whether you should eat or avoid seed oils is in the details.
  • Avoid ultra-processed foods, cook at home, and control portions to lower seed oil intake.

Seed oils like canola oil, corn oil, and sunflower oil are staples in American kitchens, while sesame and peanut oils are popular in Asian cooking. 

Recently, however, there have been debates online with some influencers on TikTok and Instagram calling seed oils “toxic” and urging people to cut them out, while experts disagree.

So, are seed oils toxic or can you use them?

Let’s dive into the seed oil controversy with expert insights from Registered Dietitian, Rita Faycurry, RD.

What are seed oils?

Seed oils are plant-based oils extracted from seeds high in oils. You’ll find them in just about everything – from French fries and stir-fries to chips, popcorn, and most restaurant meals.

This is mainly because they:

  • Can tolerate high heat (high smoke point) so they are ideal for frying, roasting, and sautéing.
  • Last a long time on the shelf without spoiling.
  • Can be produced inexpensively.

Seed oils contain monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), plus little amounts of saturated fats. PUFAs include omega-3s and omega-6s, essential fatty acids that your body needs from your diet in small amounts.

Are polyunsaturated fatty acids in seed oils bad for you?

Unfortunately, there is a lot of misinformation out there about seed oils, with some of them even called the ‘hateful 8’ for being higher in PUFAs than others. These oils are canola oil, corn oil, sunflower oil, safflower oil, soybean oil, grapeseed oil, cottonseed oil, and rice bran oil.

The biggest seed oil controversy revolves around linoleic acid, an omega-6 polyunsaturated fat essential for building cells and other vital functions. It’s linked to inflammation, but the real issue is the widespread misunderstanding of the body’s inflammatory process.

Registered Dietitian, Rita Faycurry, RD explains, “There are two types of inflammation. Linoleic acid is linked to acute inflammation, which is needed to fight infections and heal bruises. This is vastly different from chronic inflammation, which is dangerous and tied to heart disease, diabetes, and a host of autoimmune issues. Sadly, social media doesn’t always make that clear.”

In fact, studies show that dietary linoleic acid, in small amounts, is good for heart health and even reduces chronic inflammation in people with diabetes.

Should you avoid seed oils or use them?

The real issue with seed oils is that they are a key ingredient in packaged, ultra-processed and fast foods. They are found in chips, marinades, salad dressings, and many fried and baked goods—foods that aren’t the healthiest choices and contribute to serious health problems.

It is also important to consider the health effects of consuming refined vegetable oils, which are often found in processed foods and can contribute to inflammation and other health issues.

Eating too many ultra-processed foods is linked to obesity, metabolic issues, cardiovascular disease risk, diabetes, cancer, and a host of other chronic conditions.

Rita Faycurry RD advises, “There’s no real scientific evidence that seed oils are toxic. What matters is how often, how much, and in what foods you consume them. Social media trends often miss the mark on balance; there is no room for nuance. Generally, if a food is high in omega-6 fatty acids, try to limit intake but you don’t have to eliminate seed oils from your diet.”

How do you reduce seed oils in your diet?

If you're concerned about seed oils, here are some ways to cut back and reduce inflammation.

1. Avoid ultra-processed and packaged foods with refined vegetable oils

The best way to lower the amount of seed oils in your diet is to cut out ultra-processed, packaged, and fast foods. This list includes most boxed breakfast cereals, sugary drinks, and even foods marketed as healthy options like yogurt with fruit, refined breads, and ready-to-eat meals.

Many ultra-processed foods contain high amounts of vegetable oils, which can contribute to an imbalance of omega-6 and omega-3 fatty acids in the diet.

Ultra-processed foods have been directly associated with a host of health issues like diabetes, obesity, cancer, and more. Plus, according to a 30-year study, ultra-processed foods, especially processed meats, impair brain health and increase the risk of early death.

Faycurry RD elaborates, “If it comes in a box or package, try to avoid it, regardless of the oil used. Some companies now offer chips and baked goods with avocado oil, but they’re still highly refined, starchy, and inflammatory. So, how beneficial is the oil swap really? Instead, balance by swapping daily chips and sugary drinks for healthier whole foods, keeping packaged goods as occasional treats.”

2. Eat out less often; cook more at home

Restaurants aim to make their meals so tasty you’ll keep coming back, often loading them up with refined flours, and lots of fat, sugar, and salt. Often, deep-fried or oily dishes are a big draw, but this deliciousness comes at a cost: it can lead to chronic inflammation in your body.

Additionally, to save costs, some restaurants reuse their oils over and over, which makes the oils toxic.

Faycurry recommends, “If you want to lower your consumption of seed oils, try cooking your own meals at home where you can control the amount of oil you eat and your portions."

3. Bring alternative oils into your kitchen

Try cooking with avocado oil or olive oil instead. These oils come from the fruit, not the seeds, and can be good alternatives if you're concerned about seed oils.

Again, the key is to limit refined, starchy, and deep-fried foods rich in fats, salt, and sugar. Using avocado oil to deep fry potatoes will not offer the same health benefits as drizzling a little to sauté whole vegetables. Olive oil works well for low-heat cooking or in salad dressings.

4. Consult a dietitian about inflammation concerns

Diet changes can help reduce chronic inflammation. If you're concerned about inflammatory foods, consult a Registered Dietitian. They can assess your diet and lifestyle, offering a personalized anti-inflammatory diet plan to lower inflammation, reduce food cravings, and boost your health.

It’s easy to get started. Fay can help you find a Registered Dietitian near you, covered by your insurance.

The views expressed by authors and contributors of such content are not endorsed or approved by Fay and are intended for informational purposes only. The content is reviewed by Fay only to confirm educational value and audience interest. You are encouraged to discuss any questions that you may have about your health with a healthcare provider.


Fay Nutrition has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.

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Chandana (Chandy) Balasubramanian

Written by Chandana (Chandy) Balasubramanian

Chandana Balasubramanian is an experienced healthcare executive who writes on the intersection of healthcare and technology. She is the President of Global Insight Advisory Network and has extensive experience working in the medical devices and life sciences industries. Chandana holds a Master’s degree in Biomedical Engineering from the University of Wisconsin-Madison, USA.

Rita Faycurry, RD

Medically Reviewed by Rita Faycurry, RD

Rita Faycurry, RD is a board-certified Registered Dietitian Nutritionist specializing in clinical nutrition for chronic conditions. Her approach to health is centered around the idea that the mind and body are intimately connected and that true healing requires an evidence-based and integrative approach that addresses the root cause of disease. In her books and articles, Rita offers practical tips and insights on how to care for your body, mind, and spirit to achieve optimal health and wellness.