Can You Cook With Extra Virgin Olive Oil, and Does Smoke Point Actually Matter?

In short:

• Smoke point measures when an oil starts visibly smoking — not when it starts breaking down chemically.
• In a 2018 lab test, extra virgin olive oil showed the least chemical breakdown of ten oils tested, despite having a lower smoke point than most of them.
• What actually predicts how an oil holds up to heat: low polyunsaturated fat content and high polyphenol content — neither of which smoke point measures.
• Heat does reduce polyphenols over time, which means an oil’s starting concentration matters more once it’s in a hot pan, not less — keep reading to see exactly how much, and why.

In 2018, an accredited Australian lab heated ten common cooking oils to 240°C (464°F) and measured what happened to them chemically. The oil that broke down the least wasn’t the one with the highest smoke point: it was extra virgin olive oil, the oil most people are told to avoid using at high heat.
That’s because smoke point measures one thing: the temperature at which an oil starts visibly smoking. It says nothing about whether the oil is breaking down chemically. Those are two different questions, and conflating them is the entire reason “don’t cook with olive oil” advice persists.

What the study actually measured:

Leandro Ravetti, the study’s co-author and technical director at the lab that ran it, has explained the distinction plainly: smoke point is the temperature at which enough volatile compounds evaporate from an oil to produce visible smoke. It’s a visual cue, not a chemical one.

The 2018 trial (published in Acta Scientific Nutritional Health) went further than watching for smoke. Researchers heated ten oils, including extra virgin olive oil, canola, sunflower, grapeseed, rice bran, coconut, and avocado, to 240°C (464°F) in open pans, and separately held them at 180°C (356°F) for six hours in deep fryers, testing at intervals for oxidative stability, free fatty acids*, and polar compounds†, the actual chemical markers of oil breakdown.

Extra virgin olive oil produced the lowest levels of polar compounds and oxidative byproducts of any oil tested. The oils that produced the most were canola, sunflower, grapeseed, and rice bran, oils commonly recommended specifically because of their high smoke points.

Food scientists have since made the same point independently. Selina Wang, a food science researcher at UC Davis, has noted that smoke point doesn’t correlate with when an oil starts to lose stability; that stability instead comes down to an oil’s antioxidant content and fat composition.

Why smoke point misleads

Two properties actually predict how an oil holds up under heat:

• Polyunsaturated fat (PUFA) content. PUFAs are the most heat-reactive fat type. Extra virgin olive oil is roughly 10% PUFA; canola is closer to 28%; grapeseed oil runs as high as 70%. The oils with the highest smoke points in the study also had the highest PUFA content, which is a large part of why they broke down fastest, despite tolerating more heat before smoking.
• Antioxidant (polyphenol) content. These compounds protect oil from oxidizing under heat. Refined oils have had most of them stripped out during processing; extra virgin olive oil, being unrefined, retains them.

A high smoke point paired with high PUFA content and no antioxidant protection is a worse combination for cooking than a moderate smoke point paired with low PUFA content and high antioxidant protection, even though that’s the opposite of what smoke point alone would suggest.

What actually happens to the polyphenols

Antioxidant content isn’t fixed once oil is in the pan, heat reduces it. A 2020 University of Barcelona study, published in Antioxidants, tracked polyphenol loss in extra virgin olive oil at typical home-cooking temperatures: content fell by roughly 40% at 125°C (257°F, a medium sauté) and 75% at 170°C (338°F, a hot stir-fry), compared to the unheated oil.

That’s a real loss. But the researchers also noted that the heated oil still retained polyphenol levels high enough to meet the EU’s threshold for its official antioxidant health claim. The reduction is proportional — an oil that starts well above that threshold still has meaningful protective compounds left after cooking. An oil that starts close to it may not.

Which makes the concentration printed on the label more relevant once heat is involved, not less.

The bottom line

Smoke point tells you when an oil starts visibly smoking, not when it starts breaking down chemically. In the 2018 lab test, the oils most often recommended for high heat because of their high smoke points produced the most oxidative byproducts; extra virgin olive oil, despite a lower smoke point, produced the least. That gap comes down to two properties smoke point doesn’t measure at all: low PUFA content and high polyphenol content, both of which protect an oil under heat. Heat still erodes polyphenols over time — a real cost, not a myth — but it does more damage to an oil that started with less to lose in the first place.

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*Free fatty acids: fat molecules that have broken loose from the oil’s normal structure. A standard marker of oil breakdown — and one of the measures used to grade olive oil in the first place (extra virgin status requires acidity, a measure of free fatty acids, below 0.8%).

†Polar compounds: molecules that form as oil degrades under repeated heat exposure. The standard industry measure of how far an oil has broken down — it’s what regulators and commercial kitchens track to decide when frying oil needs replacing.

Resources

De Alzaa, F., Guillaume, C., & Ravetti, L. (2018). Evaluation of chemical and physical changes in different commercial oils during heating. Acta Scientific Nutritional Health, 2(6), 2–11. https://actascientific.com/ASNH/pdf/ASNH-02-0083.pdf

Lozano-Castellón, J., Vallverdú-Queralt, A., Rinaldi de Alvarenga, J. F., Illán, M., Torrado-Prat, X., & Lamuela-Raventós, R. M. (2020). Domestic sautéing with EVOO: Change in the phenolic profile. Antioxidants, 9(1), 77. https://doi.org/10.3390/antiox9010077

Why you should stop worrying about olive oil’s smoke points. (2023, April). U.S. News & World Report. https://health.usnews.com/wellness/food/articles/why-you-should-stop-worrying-about-olive-oils-smoke-points