Rated as a healthy oil, olive oil is a crowd pleaser the world over. It contains healthful polyphenols like oleuropein, hydroxytyrosol, and oleocanthal, vitamins E and K, and monounsaturated fatty acids (MUFAs), of which the chief one is oleic acid. This explains why a Mediterranean diet using olive oil extensively has consistently shown an ability to reduce cardiovascular risk factors such as high blood pressure, blood vessel dysfunction, oxidative stress, and imbalance in cholesterol and triglyceride levels.1 While extra-virgin olive oil, the healthiest variety of the oil, has entered our kitchens, it is still mostly used only on cold foods like pastas and salads and not as a cooking oil, since it is believed to be unsuitable for high-heat cooking. Modern research begs to differ. Heating does not destroy the health benefits of olive oil. Here’s a critical look at why extra-virgin and virgin olive oil can also be used as a cooking oil.
1. Olive Oil Has A Decently High Smoke Point
The idea that olive oil goes rancid upon cooking probably came from the fact that it has a low smoke point. Smoke point refers to the temperature at which a fat breaks down into smoke. Refined oils in general have a higher smoke point. Unrefined oils like extra-virgin olive oil have a lower smoke point (210°C/410 F) compared to refined oils like safflower oil (266°C/510 F). But olive oil has a higher smoke point than most unrefined vegetable oils. Considering that for any type of frying, sauteing, and deep-frying, the temperature of the oil needs to be brought up to at most 190°C or 375 F, olive oil makes the cut. It does not degrade as quickly as it is feared to.
2. Olive Oil MUFAs Oxidize Less Than Most Other Oils
Oils with a higher concentration of saturated fats fare best as cooking oils since they are least vulnerable to oxidation. The next best are the oils with more MUFAs. This is because a saturated fat molecule has no point in its structure where oxidization can occur. A monounsaturated fat molecule has a single oxidizable bond, while a polyunsaturated fat molecule has multiple.
Olive oil comprises 73% monounsaturated, 11% polyunsaturated, and 14% saturated fats. Compared to other vegetable oils like soybean oil or sunflower oil, it has a higher amount of MUFAs and fewer polyunsaturated fats (PUFAs) – soybean oil has 58% PUFAs and 23% MUFAs, while sunflower oil has 36% PUFAs and 46% MUFAs.2 What this means is that olive oil undergoes less oxidation than soybean or sunflower oil and produces fewer free radicals. Free radicals are harmful chemicals that attack cells, trigger inflammation, and lead to diseases like diabetes, heart disease, dementia, and cancer in the long term. This is why olive oil can be considered a better cooking oil than most.3 4
3. Olive Oil Polyphenols Fight The Ill Effects Of Oxidation
Since olive oil also has some PUFAs, a degree of oxidation is inevitable. But the advantage that extra-virgin and virgin olive oil have over most other oils is a high antioxidant content. These antioxidants not only prevent further oxidation of the oil and fight the free radicals generated but also enrich the food.5 One study found that deep-frying vegetables (in this study, potatoes, tomatoes, eggplant, and pumpkin) in extra-virgin olive oil increased the total phenolic content of the dish but boiling the vegetables did not. It now had oleuropein, pinoresinol, hydroxytyrosol, and tyrosol, which are olive polyphenols, in addition to the vegetable phenols like chlorogenic acid and rutin.6
Do note that you would get this antioxidative effect of olive oil most if you use extra-virgin or virgin olive oil. Refined olive oil, lite olive oil, or olive pomace oil will not have similar effects, though they would still have healthy MUFAs and an even higher smoke point because of a higher free fatty acid content. However, even refined olive oil resists oxidation longer than other refined vegetable oils. In one study, researchers deep-fried (160–190°C) and pan-fried (180°C) potatoes in 4 different refined oils – olive, corn, soybean, and sunflower – and used the same oil 10 times. Refined olive oil was found to be more heat-stable than the other seed oils during deep frying. It also underwent the least oxidative damage.7
4. Olive Oil Fumes Have Fewer Toxic Aldehydes
In one study, olive oil had to be heated in deep-frying conditions for 24 to 27 hours before it generated enough harmful compounds.8 Whether extra-virgin or regular, olive oil also produces fumes with fewer undesirable volatile aldehydes, which have adverse health effects, than other vegetable oils such as canola oil when subjected to high temperatures.9
5. Olive Oil Retains Most Of Its Nutritional Properties When Heated
Olive oil has been seen to retain most of its nutrition, like MUFAs and trace minerals even when heated. The only caveat to using extra-virgin olive oil for cooking is the loss of some, though not all, of its antioxidant phenols, including hydroxytyrosol, and vitamin E, due to oxidation, hydrolysis, or polymerization. The amount of loss depends on the cooking method and duration of cooking as well as the cultivar of the olive.10 11 12
A study tested 3 types of olive oils with different phenol contents of 140 mg/kg, 300 mg/kg, and 450 mg/kg. The oils were heated to 121°C and 180°C on a stovetop for 10 minutes and baked in an oven for 30 minutes at 204°C. It found that loss of phenols is least when the oil is used to bake or is heated to 121°C. Oleocanthal, the antioxidant that gives olive oil its pungency, however, was found to be heat resistant.13
To minimize loss of phenols like hydroxytyrosol or oleuropein, which give olives many of their benefits, cook with extra-virgin olive oil below the smoke point and for short baking sessions.14 If you want the full stack of polyphenols, a quick saute or a light fry as well as poaching with extra-virgin olive oil is a better option than deep frying, pan frying, or searing.
So to sum it up, yes, you can use extra-virgin olive oil as a cooking oil without fear of losing all the benefits. It has a considerably high smoke point, can resist oxidation, does not give off toxic fumes, and does not lose all its healthy polyphenols and antioxidants on heating. Rather, it enriches cooked vegetables. All in all, it’s a healthier option than most other cooking oils.
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