The health benefits of extra-virgin olive oil are well-documented and the flavorful oil, a staple of the Mediterranean diet, is a favorite among professional chefs and home cooks alike. However, there is a common misperception that cooking with olive oil destroys all its of antioxidants and polyphenols. A recently published study by the University of Barcelona in the Journal Antioxidants (1) once again confirms that extra virgin olive oil retains significant amounts of these healthy compounds during cooking.
The study's researchers sought to determine how much normal cooking, at temperatures from 120°C to 170°C (258°F/338°F) would reduce the phenolic and antioxidant content of raw oil. Antioxidants, like vitamin C and E, play a crucial role in preventing cell damage from free radicals, and EVOO contains 500% more antioxidants than other common oils such as avocado and coconut oil.
In the lab, using an hojiblanca olive oil with a moderate level of polyphenols, researchers simulated home cooking conditions and found that while the polyphenol content decreased by 40% at 258° F and 75% at 338° F compared to raw EVOO, the levels of antioxidants and polyphenols remained relatively high.
Lead researcher Julián Lozano explained that “despite the decrease in concentration of polyphenols during the cooking process," the oil after heating still had sufficient levels of polyphenols to qualify for the health claim authorized by the EFSA (the European FDA) for olive oil polyphenol content, which include such benefits as LDL cholesterol reduction and anti-inflammatory effects.
It is important to note that in this study, the oil was heated to normal cooking temperatures, but was not used to actually cook food. The study thus did not consider the extent to which some of the polyphenols and antioxidants that were lost might have been protected by transferring to the food, as was discovered in another recent study that found food prepared in olive oil will be imparted with additional antioxidants during the cooking process. (2)
The results of the 2020 Barcelona study bolster the growing knowledge base around the effects of cooking with olive oil. In the past five years, research has shown that:
- The levels of antioxidants present in olive oil make it very stable even at high temperatures and therefore one of the safest oils to use for cooking. (3)
- The antioxidants in olive oil are “reasonably heat-resistant” and that "a significant number of total phenols and individual phenols stayed intact up even after heating up to 220°C". (4)
- Olive oil can be heated to frying temperatures multiple times without creating trans fats. (5)
Taken together, these studies dispel the myth that cooking destroys the unique health benefits associated with extra virgin olive oil.
- Domestic Sautéing with EVOO: Change in the Phenolic Profile
- Phenols and the antioxidant capacity of Mediterranean vegetables prepared with extra virgin olive oil using different domestic cooking techniques.
- Evaluation of Chemical and Physical Changes in Different Commercial Oils during Heating
- Changes In Chemical Compositions of Olive Oil Under Different Heating Temperatures Similar to Home Cooking
- Effect of phenolic extracts on trans fatty acid formation during frying