There's new research on the best oils to cook with. If you’ve been hesitant to use extra virgin olive oil for high heat cooking, read on.
Nutrition Diva listener Ann writes:
“I sauté and roast vegetables often and have been trying to figure out what is the best oil to use. I was under the impression that I should not use extra virgin olive oil (EVOO) because it does not have a high smoke point. I know you addressed this in 2011, and am wondering if this or any other studies since then have changed your recommendation?”
In fact, there was a great study done just last year that confirms a lot of what I discussed in my previous article on cooking with oils but adds some important new information.
Perhaps you’ve seen charts that list the exact temperature at which various types of oil will begin to smoke. But these figures are not nearly as reliable as you might think.
First, let’s clear up some misunderstandings about smoke point. Perhaps you’ve seen charts that list the exact temperature at which various types of oil will begin to smoke. But these figures are not nearly as reliable as you might think.
There are many factors that impact smoke point even more than what plant (or animal) the oil comes from. If an oil has already been heated, for example, its smoke point will be quite a bit lower the second time. Refined and filtered oils will generally have a higher smoke point than unrefined and unfiltered oils, but even this is a generalization with lots of exceptions. The age of an oil may be a factor. Adding other foods to the oil may also alter the smoke point.
Although the exact temperature at which an oil will start to smoke in any given situation may be hard to predict, it’s pretty easy to tell when you’ve reached it. (Your first clue is the bluish smoke that starts to fill the air.) This is something you definitely want to avoid. But, like Ann, I frequently saute and roast vegetables in oil and I use extra virgin olive oil. The only time I can ever remember having olive oil start to smoke was when I put it in a skillet, turned on the heat, and got distracted doing something else in the kitchen.
Quick and Dirty Tip: If your oil has gotten too hot and started to smoke, it's best to let it cool and discard it.
Smoke point is not the biggest factor
Smoke point is not the primary consideration.when choosing a cooking oil. A greater concern is the formation of HNEs, a toxic compound created when highly unsaturated oils are heated. Unlike smoke, HNEs are odorless, flavorless and invisible.
Your best protection against HNE formation is to avoid high-heat cooking with oils that are high in polyunsaturated fats. This includes grapeseed, sunflower, safflower, and rice bran oil. Oils that are high in monounsaturated fats, such as avocado and olive oil, or saturated fats, such as palm and coconut, will produce far less HNE when heated.
Surprising News about Extra Virgin Olive Oil
These were all issues that I discussed in my previous article. But last year, a group of Australian researchers did a very comprehensive analysis of ten common cooking oils to see which ones were the most stable at high heat.
In addition to looking at smoke point and the formation of harmful by-products like HNE, the Australians also studied the tendency of oils to form free radicals when heated. They looked at antioxidant capacity of the oils. They tested the effects of heating to various temperatures and holding them at high temperatures for various lengths of time.
I’ll spare you all the boring details (although here is a link to the study if you want to geek out on lipid peroxidation, oxidative stability and UV coefficients.)
Here’s the upshot of all of this analysis:
Although it does not have the highest smoke point, extra virgin olive oil turns out to be one of the best choices for high-heat cooking,
Although it does not have the highest smoke point, extra virgin olive oil turns out to be one of the best choices for high-heat cooking, based on its superior ability to resist oxidation, as well the low formation of harmful compounds. That’s right: extra virgin olive oil was more stable than light or refined olive oil, perhaps because it is higher in antioxidants. (Those same antioxidant compounds, by the way, are a big factor in the characteristic aroma and flavor of really high quality olive oil.)
The other standout in this comparison was coconut oil. Coconut oil has a much higher smoke point than extra virgin olive oil and performed similarly in terms of the formation of harmful compounds. One thing to note is that it was not quite as resistant to oxidation. Coconut oil is, of course, also much higher in saturated fat and (correspondingly) lower in monounsaturated fat.
Coconut oil remains a good choice for high heat cooking. But if you have been anxious about cooking with extra virgin olive oil, worry no more! This healthful and delicious oil is also healthful when heated.
You may still want to save your really expensive unfiltered extra virgin olive oil for off-heat uses. It would be perfectly safe to cook with but you might not get quite as much of the subtle flavor and aroma that you’re paying a premium for. Keep a more economical extra virgin olive oil on hand to cook with and drizzle the fancy stuff on at the end.
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