Are you a fan of Olive Oil? I love it for its healthy properties and delicious taste. There are lots of brands of Olive Oil and when it comes to Extra Virgin Olive Oil the varieties and depths of flavour available make it akin to a passion for fine wines.
Olive Oil is rich in ‘monounsaturated fatty acids’ and a key part of the ‘Mediterranean Diet’.
Research has demonstrated that the populations from the Mediterranean region have longer life expectancies and lower risks of heart disease, high blood pressure and stroke, as compared with North Americans and non- Mediterranean Europe.
Monounsaturated fatty acids
These benefits are attributed in part to the diet being plentiful in fruit, vegetables, nuts, pulses, fish, but also plentiful in Olive Oil – a major component of the diet. Monounsaturated fatty acids (MUFAs) are considered a healthy dietary fat, whilst saturated fats such as animal fats should be only used sparingly, or (depending on your viewpoint) not at all. ‘Trans fats’ are in most cases to be completely avoided and fortunately ongoing publicity on this issue is informing the public and of this fact*.
So the question is ‘Is it okay to cook with Olive Oil?’ I know that many people do so as they assume that it is a healthier option than cooking in other oils popular for frying. Common examples might be to fry a steak, chop or fish portion; or for a stir-fry for example. However there are occasions where using Virgin and Extra Virgin Olive Oil to cook with should be avoided and other oils used. Let me explain why.
The ‘smoke point’
Any oil you heat to cook with has a ‘smoke point’ – and the smoke point temperature varies for every oil. The smoke point is self-explanatory in that it is the temperature at which visible vapour (or smoke) becomes evident. In cooking the smoke point is commonly used as an indicator for when decomposition of the oil begins.
Importantly not only will a smoking oil affect the flavour and nutritional content of the oil – the decomposition means that chemical changes are occurring to the oil that may not only result in reduced flavor and nutritional value but also the generation of harmful compounds termed free radicals or similarly oxygen radicals. There are compounds that are harmful to our health and they are linked to DNA cell damage and cancer incidence.
For this reason it is clearly important in cooking not to heat any oil or fat past its smoke point. It should also be noted that inhaling the vapours from a smoking oil can also be health damaging.
A smoking oil or fat (i.e. at or beyond its smoke point) is the temperature at which it is breaking down to glycerol and free fatty acids. The glycerol is then further broken down to acrolein which is a component of the smoke. Unfortunately the oil is now turning to a trans fat (transesterification). Trans and hydrogenated fats and polycyclic aromatic hydrocarbons are carcinogenic and inflammatory because they go into the cell membranes in our body and by virtue of their shape destabilise membranes.
Olive Oil and Extra Virgin Olive Oil
So how does this all apply to Olive Oil and Extra Virgin Olive Oil in particular? One reason is that when an oil is refined the process increases the smoke point of the oil – the higher the smoke point the higher the temperature the oil has to be heated to before it smokes. Many cooking oils are refined for that reason.
With Extra Virgin Olive Oil only mechanical means have been used to press or extract the oil from the olives. With refined oils chemicals are used to extract the oil. In principle therefore a cold-pressed extra virgin olive oil should have the lowest smoke point of all forms of olive oil as it has been the least refined.
Going back to the Mediterranean Diet and the beneficial monounsaturated fat (MUFA) content – Olive Oil has one of the highest contents of MUFA in a vegetable oil. One aspect of research into the Mediterranean Diet has focussed on the oleic acid content of Olive Oil (oleic acid is a MUFA). The natural content of antioxidant polyphenols in Olive Oil is also considered very important.
Many of you who are fans of Olive Oil will use it primarily in its raw form straight from the bottle. Extra Virgin Olive Oils, for example, have wonderful nutty and fruity flavours and are ideal for simple salad and vegetable dressings, in dips, on pasta and potatoes, and hundreds of other tasty ways.
Typical smoke points of oils are widely available online including from oil manufacturers. But every batch of oil will vary depending on numerous factors including the refinement of the oil, whether it is organic etc. Don’t forget that Olive Oil comes in different forms including refined versions too.
And please do not get scared away from using Olive Oil to cook with, its only when an oil is smoking with a bluish smoke that you should think twice before cooking. Many of you will heat Olive Oil gently to sauté onions etc. as the basis of a sauce for example. A good example of where to think twice is an oil smoking in a pan at a high temperature before you have added any foods. When cooking with a wok for example chefs will recommend certain oils as they have a high smoke point and are better suited to this form of cooking.
* In respect of avoiding trans fats there are exceptions to every rule and in this instance CLA (conjugated linoleic acid) found in cow’s milk and butter is a valuable, albeit essential trans fat; and coconut, by virtue of its fatty acid profile is a valuable saturated fat – all in moderation of course.
If you have any questions regarding this article, any of the health topics raised, or any other health matters please do contact me (Amanda) by phone or email at any time.
Cytoplan Blog: The Mediterranean Diet & Heart Health