Can I cook with olive oil?

In the traditional regions of the Mediterranean, olive oil is and always has been an everyday food. It is used to cook with across all cooking mediums including deep-frying, baking, and roasting. It’s also used as a dressing, in sauces, marinades, and as a condiment alone. It truly is a cornerstone of the Mediterranean Diet. 

Having grown up in a Greek-Australian family, extra virgin olive oil (EVOO) was the single oil we used to cook with. Butter aside, which was only really used to spread on toast or in the occasional baked good, I don't actually remember there ever being any other kind of oil in the house. I never really gave this much thought… It was the norm in my family and the same with my friends of similar backgrounds. This is the way my grandmother cooked, how my Mum cooked and how I learned to cook. To this day I simply can't imagine starting off a dish using anything other than EVOO and admittedly, for a household of two, we go through copious amounts of the stuff. 

But despite the fact that this oil has been used in this way for generations, there’s been no shortage of controversy around its suitability for cooking. In the past, there have been those who advocated for olive oil to only be used for finishing or dressing dishes - and this is largely due to the smoke point. 

What is a smoke point?

The smoke point of an oil is simply the temperature at which the oil produces a continuous stream of smoke. This is the method that has generally been used to establish an oil’s safe use and suitability to cook with. It is what has historically been taught as the standard for ranking cooking oils, and even throughout my relatively recent nutrition degree, the smoke point chart was heavily referenced. 

The fact that the smoke point of EVOO is lower in relation to some other oils and fats, is why canola oil and butter have historically been recommended as a superior cooking choice, particularly for higher temperature cooking. But then how is it then that the Mediterranean Diet, which relies so heavily on the use of EVOO, is known to be one of the world's healthiest diets? 

Most recent research tells us that there is in fact a poor correlation between an oil’s smoke point and its performance when it’s heated (1). In other words, the smoke point is not the best measure of an oil’s suitability for cooking or health. This research tells us that other measures, namely the oxidative stability of an oil and the polar compounds produced, are better predictors of an oil's performance when heated (1,2).

What are polar compounds?

Very simply put, polar compounds are by-products that are produced when oil breaks down (such as when exposed to heat). Evidence shows that these compounds are linked to increased oxidative stress within the body and a higher risk of developing neurodegenerative conditions such as Alzheimer’s and Parkinson’s Disease (3,4)

A 2018 study found that ​​of all the oils tested, it was actually EVOO that produced the lowest level of harmful polar compounds and that these compounds were in fact higher in refined and seed oils such as canola oil, grapeseed, sunflower, and rice bran oils (1).  

The study concluded that EVOO was the most stable oil when heated….and here's why: 

1. EVOO is extremely high in antioxidants which, aside from imparting independent health effects, protect the oil from breaking down during cooking (5)
   
   

2. EVOO is high in mono-unsaturated fatty acids which are less prone to oxidation and degradation when heated compared to polyunsaturated fats, which are dominant in many refined oils (6). 
   
   

3. EVOO undergoes minimal processing and by mechanical means only. Comparatively, refined oils are produced by a combination of mechanical, heating, and chemical processes that leave the oils with high levels of oxidative by-products before they are even used to cook with. This also means that they are more readily oxidised thereafter.

But the benefits of cooking with EVOO are not limited to its stability… 

By absorbing the oil in which it’s cooked, the food is also protected from oxidation and becomes enriched with EVOO health-promoting bioactive compounds.

Conversely, when you cook with EVOO the phytochemicals in the foods migrate to the oil, further increasing its bioavailability and stability (6). And finally, cooking with EVOO enhances the absorption of fat-soluble vitamins and beneficial components of food such as carotenoids and glucosinolates found in a range of vegetables (7). 

So, despite the widespread misconceptions about olive oil’s suitability for cooking, we now know that generations past actually had it right! Extra virgin olive is not only suitable for all types of cooking methods but also comes with a host of health benefits. In fact, EVOO is now being recommended to improve clinical risk factors for chronic diseases such as blood lipids, blood pressure, and chronic inflammation. Simply switching the primary oil in your diet to EVOO, is a great way to see some of these health benefits, and start to align your diet with the Mediterranean way of eating. 

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References:

1. 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): 02-11.

2. Pooja, C., & Sukhneet, S. (2020). Polar Compounds in Frying Oils: A Review. Applied Ecology and Environmental Sciences, 9(1), 21–29.

3. Matveychuk, D., Dursun, S. M., Wood, P. L., & Baker, G. B. (2011). Reactive Aldehydes and Neurodegenerative Disorders. Klinik Psikofarmakoloji Bülteni-Bulletin of Clinical Psychopharmacology, 21(4), 277–288.

4. Jinwei L, Xiaondan L, Wenci C et al. Comparison of different polar compounds-induced cytotoxicity in human hepatocellular carcinoma HepG2 cells. Lipids Health Dis.2016;15:30. 

5. Cicerale, S., Conlan, X. A., Barnett, N. W., Sinclair, A. J., & Keast, R. S. J. (2009). Influence of heat on biological activity and concentration of oleocanthal—A natural anti-inflammatory agent in virgin olive oil. Journal of Agricultural and Food Chemistry, 57(4), 1326–1330.

6. Lozano-Castellón, J., Rinaldi de Alvarenga, J. F., Vallverdú-Queralt, A., & Lamuela-Raventós, R. M. (2022). Cooking with extra-virgin olive oil: A mixture of food components to prevent oxidation and degradation. Trends in Food Science & Technology, 123, 28–36.

7. Alzaa, A. F. de, Guillaume, C., & Ravetti, L. (2021). Cooking with Extra Virgin Olive Oil. Olive Oil - New Perspectives and Applications [Working Title].

8. Ramírez-Anaya, J. D. P., Samaniego-Sánchez, C., Castañeda-Saucedo, M. C., Villalón-Mir, M., & de la Serrana, H. L.-G. (2015). Phenols and the antioxidant capacity of Mediterranean vegetables prepared with extra virgin olive oil using different domestic cooking techniques. Food Chemistry, 188, 430–438.