How do I purchase a “good” olive oil? Should I heat it? Is it only to be used raw?
These are questions I'm often asked by patients.
I've been using olive oil raw for salad dressings, and coconut and avocado oil for cooking for a long time now, believing that the smoke point was lower, and therefore health damaging rather than promoting, at high heat.
Thankfully my membership in Dr Jordan Robertson ND's clinician research hub introduced me to Dr Antonella Aguilera Ruiz ND, a naturopathic doctor based in Northern California who is a Mediterranean Diet expert. Extra virgin olive oil is in its own category of the validated Mediterranean diet scales used in studies such as the PREDIMED for cardiovascular health and later the SMILES trial for depression. She explored what we know about it and the evidence on how to counsel patients on engaging with this important aspect of the Mediterranean diet.
Extra virgin olive oil is a key component of the Mediterranean diet and can be used for all types of cooking. It can be used raw, to pan fry, sauté, roast and even bake. However, you do want to search out an extra virgin olive oil as this is the highest grade oil and what has been used in studies and traditionally within the Mediterranean eating pattern.
Extra virgin means that the olives have been pressed very close to harvest without exposure to excess heat and the resulting oil is of high nutritional quality.
To be sure you’re purchasing extra virgin olive oil, look for the following:
The label clearly says Extra Virgin Olive Oil
It’s stored in a dark glass bottle (this helps protect the oil from light and prevent degradation)
A harvest date within the past 18-24 months. Olive oil is harvested in the late fall, so if you’re purchasing in 2023, you’d want a harvest date from Nov/Dec 2022, ideally.
Look for a seal (if possible):
California: COOC seal
Europe: Protected Origin of Destination
International: International Olive Council (IOC) or Extra Virgin Alliance (EVA)
Above is a beautiful illustration from the research of how heating olive oil (OO) does not produce harmful trans fats. EVOO refers to extra virgin, and V to virgin olive oil in the study.
Unlike wine, olive oil does not get better with age! Once it’s opened, light, heat and oxygen will begin to oxidize it, so you want to use it in your regular cooking versus keeping it for special occasions. Once a bottle is opened, it is best to use the oil within 3 – 6 months. Store oil in a cool, dark cabinet or pantry.
Alvarenga, J. F. R. de, Quifer-Rada, P., Juliano, F. F., Hurtado-Barroso, S., Illan, M., Torrado-Prat, X., & Lamuela-Raventós, R. M. (2019). Using Extra Virgin Olive Oil to Cook Vegetables Enhances Polyphenol and Carotenoid Extractability: A Study Applying the sofrito Technique. Molecules, 24(8), 1555. https://doi.org/10.3390/molecules24081555
Carvalho, A. G. A. de, Olmo-García, L., Gaspar, B. R. A., Carrasco-Pancorbo, A., Castelo-Branco, V. N., & Torres, A. G. (2022). Evolution of the metabolic profile of virgin olive oil during deep-frying: Assessing the transfer of bioactive compounds to the fried food. Food Chemistry, 380, 132205. https://doi.org/10.1016/j.foodchem.2022.132205
Estruch, R., Ros, E., Salas-Salvadó, J., Covas, M.-I., Corella, D., Arós, F., … Investigators, P. S. (2018). Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. New England Journal of Medicine, 378(25), e34. https://doi.org/10.1056/nejmoa1800389
F, de A., C, G., & L., R. (2018). Evaluation of Chemical and Physical Changes in Different Commercial Oils during Heating. Retrieved September 28, 2022, from Evaluation of Chemical and Physical Changes in Different Commercial Oils during Heating website: https://actascientific.com/ASNH/pdf/ASNH-02-0083.pdf
Jacka, F. N., O’Neil, A., Opie, R., Itsiopoulos, C., Cotton, S., Mohebbi, M., … Berk, M. (2017). A randomised controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial). BMC Medicine, 15(1), 23. https://doi.org/10.1186/s12916-017-0791-y
Lozano-Castellón, J., Vallverdú-Queralt, A., Alvarenga, J. F. R. de, 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