When I ask the question from the title of this article during my workshops, as an answer, I usually hear “no!”. And then there are reasons why not. Whereas, this matter is not that obvious, because, as it often happens in case of various food products, many common theories about olive oil are not justified.
But that's not all...
Olive oil is very rich in oleic acid (app. 68 – 75%), which is an advantage, by the way, it is poor in saturated fat (10 – 15% of the content) and polyunsaturated fat (app. 8 – 12% of the content). Apart from the mentioned lipids, olive oil also contains many compounds with antioxidative, antipatelet, anti-inflammatory and anti-cancer properties (they occur in significant concentration only in the Extra Virgin olive oil). I mean, the substances are following:
and many others.
The positive influence of the intake of olive oil on human health is the subject of many studies, but not so many of them suggest that the benefits from regular consumption of such oil are quite extended:
Olive oil and thermal treatment
As far as in the matter of pro-health properties of high-quality olive oil there is rather common compliance, when it comes to the aspect of the potential use of this kind of fat to frying, the opinions are different. On the one hand, you can hear the statements that in the supposed healthy Mediterranean diet, frying with olive oil has been performed every day, and on the other, there are individuals stating, that the unsaturated fatty acids found in this kind of fat oxygenate easily because of high temperature and they undergo the process of isomerization, which leads to creating harmful chemical compounds. Who is right this time?
Not that simple issue
In general, a lot of things depend on... the kind of olive oil. Particular versions of this fat have various thermooxidative stability, which is noticeable in a form of, e.g. “smoke point”. Smoke point sets the lowest temperature in which the heated kind of fat starts to break into glycerol and free fatty acids, and then it releases the harmful acrolein. It is assumed that the higher the smoke point of a particular kindof fat, the more resistant lipids for breakdown are found in it.
In case of olive oil, the smoke point ranges between 170 to 240 *C. Is it good? Well, in order to answer this question, you have to first wonder what temperature you use for frying at home.
It's good to know, that if you just parboil (meat, fish, vegetables), the temperature in the frying pan is rather lower than 160 *C. But it's different in case of intensive, deep frying – then the temperature may be significantly higher. Another thing is the choice of olive oil – if you choose high-quality product with low acidity, the smoke point will be higher.
That matter seems quite complex, and, to make it even worse, it's good to add that the smoke point itself is not the best ranking system letting us assess the usability of particular kind of fat to use as a mean for thermal treatment of food. The best example is refined sunflower seed oil in this case, which has high smoke point (240*C), but it's not that good for frying. Why? It is rich in polyunsaturated acids, which are easily oxidated, which is accompanied by creating harmful substances. And here you could think, that the situation is so complicated, that it's hard to draw any useful and practical conclusions from it. But it's not that bad in reality.
First of all, you have to agree, that if you don't use deep frying in the kitchen (when the temperature of the frying medium may reach 200*C), and you prefer shallow frying (when the temperature ranges between 130 – 160 *C), you should not worry too much that one kind of fat has the smoke point of 180, not 240*C. It doesn't really matter that much.
Second of all, if you want to include the measurements of the adverse changes in fats under the influence of high temperature, it would be good to take under consideration the results of the so-called Rancimat test, which is a commonly used method of setting the oxidative stability. This test is based on the accelerated process of ageing of the taken sample by subjecting it to the activity of high temperature and oxygen. You can read more about the test here:
And so, olive oil looks really well in that test. So-called induction time in the test is 6.44 – 16.01 h for Extra Virgin olive oil and 6.20 – 8.15 h for refined olive oil.
Olive oil and research
Generally speaking, however, the most important fact is that the thermooxidative stability of olive oil has been assessed in scientific studies in detail. And, what's interesting, against common opinions, olive oil turned out to cope with high temperature really well! What's more, the authors decided, that olive oil could be good even in industrial frying (which lasts for a long time and takes place in higher temperature than in home conditions). The publication linked below may be a good example:
The results of the study linked above are not the only ones. It can be said that they match the set of conclusions drawn from other experiments, where olive oil has turned out to be a great kind of fat for thermal treatment many times, and – the best result was for the Extra Virgin one, i.e. that, which should definitely not be used for frying according to common opinions! Additionally, there is some limited evidence that frying on olive oil doesn't have to be harmful, and it may be even advantageous for health:
When frying in home conditions, we can easily use olive oil as a frying mean, also that Extra Virgin one (it contains antioxidants, which protect lipids from oxidation). Common gossips, according to which during heating this kind of fat there occur harmful substances, are exaggerated and not justified. Comparing to other kinds of fat, olive oil looks quite positively when it comes to the usefulness to thermal treatment. The only flaw is that it turns out to be... quite expensive, at least if we talk about high-quality olive oil with low acidity (i.e. by the way, with higher thermooxidative stability).