Growing up in a Mediterranean household no meal was complete without a large glug of extra virgin olive oil (EVOO), be it drizzled on a salad or to lightly fry fish or meat. It’s how my parents and grandparents explained their youthful glow. But then, in the early 1990s British TV chef Anthony Worrall Thompson seemingly started us believing that cooking with olive oil was dangerous. As such, along with most households, we made the shift to cooking with sunflower oil. Fast forward another decade or two and the oil debate continues, only now there are new enemies on the scene. Today, growing suspicion falls on highly-processed seed oils – and that includes the sunflower oil we switched to.
But do they really deserve all the negative press?
Let’s take a look.
What are seed oils?
You’ll recognize the most common seed oils in your grocery store or home pantry: canola, corn, cottonseed, soybean, sunflower, safflower, grapeseed, and rice bran. Dubbed “the hateful 8”, they have recently emerged as a source of concern despite years of popularity.
Thanks to clever marketing, these highly-processed oils initially became household names in the early 1900s. Manufacturers, like Procter & Gamble with Crisco, promoted the oils as healthy alternatives to the saturated animal fats used at the time such as butter, lard or tallow. They were affordable and easy to store and a cooking trend blossomed. Over the years more refined oils were developed.
However, mass production and popular consumption is not an indicator of what’s actually good for us.
“Seed and vegetable oils sound so ‘natural’ but there’s nothing natural about the refining process,” explains Suzan Terzian, an Abu Dhabi-based clinical nutritionist and holistic health coach. “They undergo heating, oxidation, and processing with a petroleum-based solvent. Then they’re coated with more chemicals to mask their scent.”
“They are not healthy foods,” agrees Sinead Kelly, nutritionist and naturopath, who points out that the industrial seed oils were originally used in the soap-making process. “So why should these industrial oils be on our food and plates?”
Are seed oils toxic?
Despite many experts highlighting the alleged dangers of seed oils, there is still a lot of confusion and over-simplification of the subject. In fact, according to a consumer report there is still insufficient research to accurately claim that the oils are toxic.
“Much like carbohydrates and fats, not all seed oils are created equally,” explains Dr Nasr Al-Jafari, medical director at DNA Health Corp. “Therefore, to taint all of them all as toxic is erroneous. Similarly, to say all seed oils are safe is problematic.”
There is an argument that seed oils have some health benefits as they contain two polyunsaturated fatty acids – linoleic acid (an omega-6 fat) and alpha-linolenic acid (an omega-3 fat) – that are essential nutrients. They are called ‘essential’ because they must be obtained through diet as our bodies do not naturally produce them.
“Every cell in the body needs essential fatty acids (EFAs) for proper structure and function. EFAs promote healthy nerve activity, help produce hormones, and play a role in inflammation,” explains Dr Al-Jafari.
The key, however, is in getting the right balance. “The established adequate intake for an adult suggests a higher ratio of omega-6s to omega-3s, although some research suggests that ratios 4:1 and lower may reduce inflammation and lower the risk of chronic disease.”
As ever with diets, moderation is key – an over-consumption of seed oils can lead to an unhealthy imbalance, playing a significant role in chronic inflammatory diseases. Kelly explains, “A diet high in omega-6 from industrial seed oils promotes chronic inflammation. And, inflammation is a silent killer that is a catalyst to many ailments, including asthma, osteoarthritis, heart disease, infertility, IBS and IBD, macular degeneration, diabetes, obesity and autoimmune disease, as well as cognition and mental health issues.”
However, as omega-6s are essential, instead of cutting back, seek out healthier, alternative sources.
“If our overall goal is optimal health, then we must remove industrial seed oils from our diet,” Kelly explains. “Instead, get your omega-6s from whole food sources such as nuts and poultry and balance with omega-3 fatty acids from shellfish, seafood and fish oil.”
Seed oil smoke points
When oils like soybean, corn, canola, sunflower and safflower are heated they produce high levels of free radicals. According to Dr Al-Jafari, these free radicals can cause damage to “fatty tissue, DNA and proteins in the body, which can lead to vast diseases over time”.
That’s why it’s imperative to understand an oil’s smoke point. This refers to the point in which the oil starts to burn when heated. A high smoking point means the oil can withstand high heat. The more refined the oil, the higher the temperature it can take in cooking, which is why seed oils are so popular in fast food restaurants and deep frying.
So what should you cook with? “Saturated fats like grass fed butter, grass-fed ghee and coconut oil are the most stable when heated,” explains Terzian. “They are the safest for our bodies. Olive oil is high in monounsaturated fat, which is also heat-stable; it is also loaded with antioxidants which protects against any oxidation [harmful compounds] that can take place. You don’t want fragile oils like sunflower oil and canola oil, loaded with polyunsaturated fats, that are going to be chemically altered under heat and become unhealthy.”
At Sweet Greens restaurant in Abu Dhabi, the chefs only cook with EVOO and Extra virgin coconut oil (EVCO).
“We use one of these depending on what the recipe calls for, based on the rest of the ingredients,” explains Nikhil Hemnani, CEO of Sweet Greens.
As for old misconceptions that it’s better to cook with seed oil than EVOO, Hemnani explains: “On a nutritional label, both these oils have a lot of similarities from calories to total fat per tablespoon. But the main difference is that olive oil has polyphenols [antioxidants] that protects the human body from aging and other diseases.”
Kelly and Terzian warn against overheating olive oil. Terzian claims doing so causes it to lose some of the beneficial nutrients, while Kelly cautions: “heated at too high a heat point it can become carcinogenic. So, it should only be used on low to medium heat.”
Luckily, smoke point is not an issue at Sweet Greens, with the chefs favoring a low to medium heat approach to preserve the nutrients of their meals, and no seed oils because they are highly reactive and unstable.
“We use premium ingredients only and seed oils sold in this region are highly processed,” said Hemnani. “The more processed or refined the oil, the lower the nutrient content of the oil and that doesn’t align with our ethos.”
Seed oil alternatives
Ultimately, to determine which oil is best it depends on the type of cooking you’re doing and the oil’s smoke point – heat it too high and you lose flavor, nutrients, and release harmful molecules. Kelly shares her top picks:
Extra Virgin Olive Oil
Always choose ‘extra virgin’ which means that the oil is unrefined and has more nutrients, antioxidants, and heart-healthy fats. It is also rich in the antioxidant vitamin E and polyphenols, which have a wide range of health-promoting properties, including cardioprotective and anti-diabetic properties. Compared to other oils, olive has a low smoke point, so it’s best used for medium to low-heat cooking, baking, or as dressings on salads.
It doesn’t have much flavor, so it will never overpower your cooking. However, it’s full of vitamin E and boasts a lot of the same benefits as extra virgin olive oil, but with a higher smoking point, making it great for sauteing or pan frying.
It is a superfood with many health-promoting properties. It can help improve cholesterol, kill harmful bacteria, and boost metabolism. Coconut oil contains 90% saturated fat, which makes it very heat stable. Also coconut oil has a high smoke point, meaning it can be heated to a high temperature.
Butter & Ghee
Butter and ghee from grass-fed animals contain conjugated linoleic acid, a type of fatty acid with anti-cancer and metabolic health-promoting properties. While butter may contain traces of milk proteins, ghee is usually a safe option even for dairy-sensitive people because all milk constituents are removed in its creation. Both have a high smoke point.
It has a delicate flavor and similar fatty acid profile to olive oil. It has a high smoke point, making it great for high-heat cooking.
The conclusion — for now
While the studies are still ongoing, for optimal health the majority of experts seem to agree on avoiding heavily-refined oils and over-heating oils with a low smoking point.
“Preferable oil choices are minimally refined, cold-pressed, organic, non-GMO fats and liquid oils as these are of the best quality,” says Dr Al-Jafari, adding, “Fats and liquid oils break down in heat, light, and oxygen, so the quality and storage of these oils is also important. Keep oils in dark glass, not plastic, containers and discard if they smell rancid.”
Another key lesson here is to be wary of 1990s TV chefs, do your research and enjoy high quality EVOO.
This story originally ran in November 2022.