Lang
A 2018 laboratory study has resurfaced as a key reference in the debate over which cooking fats hold up best under high heat, with extra virgin olive oil (EVOO) emerging as the most heat-stable option among ten commercial oils tested.
The paper, 'Evaluation of Chemical and Physical Changes in Different Commercial Oils during Heating,' published in Acta Scientific Nutritional Health, subjected the oils to two heating protocols: a rapid ramp to 240°C (464°F) and a sustained six-hour hold at 180°C (356°F) — the kind of temperature common in home frying and roasting. The researchers tracked oxidation, polar compound formation, fatty acid shifts, trans-fat development and smoke-point behaviour. Polar compounds, a recognised marker of oil degradation, are typically treated as a discard trigger by commercial kitchens once they reach roughly 25 percent.
After prolonged heating at 180°C, the refined seed oils generated markedly more polar compounds than EVOO. Sunflower oil reached 21.75 percent, grapeseed 20.24 percent, canola 17.32 percent and rice bran 15.66 percent. EVOO, by contrast, sat at the bottom of the degradation table at approximately 10.5 percent, with coconut oil just behind it.
The authors attributed EVOO's resilience to its high oleic acid content and to its natural antioxidant profile, particularly polyphenols. Oils richer in polyunsaturated fatty acids, they noted, generally broke down faster.
Perhaps the most provocative finding for kitchen practice: the study found that a higher initial smoke point did not guarantee better performance under heat, and could in some cases correlate with greater polar compound formation after prolonged heating. Chemical stability, fatty acid composition and the presence of protective antioxidants proved more reliable indicators.
The result carries cultural weight in Greece, where EVOO is the everyday household fat — used for horta, potatoes, fish, beans and the Sunday roast — rather than a finishing specialty. Long-standing nutrition advice has steered cooks away from EVOO at high heat on the basis of its comparatively modest smoke point. The study argues that framing misses the chemistry that actually determines degradation.
The researchers acknowledge two important limitations. The oils were heated without food, so the introduction of water, steam and ingredients in real cooking may alter outcomes. The work is also a single laboratory comparison of commercial samples, not a clinical trial of health outcomes.
Even with those caveats, the ranking is striking: of the ten oils tested, EVOO was the most heat-stable, despite not having the highest smoke point. For Greek kitchens already built around the fat, the conclusion aligns with practice — the durability of a cooking oil depends less on the temperature at which it first smokes and more on the structure of the fat itself and the protective compounds that remain in the bottle.
Source: De Alzaa F, Guillaume C, Ravetti L. Evaluation of Chemical and Physical Changes in Different Commercial Oils during Heating. Acta Scientific Nutritional Health. 2018;2(6):2-11.