I have the pleasure to introduce this article that my friend and Biotechnologist, Ximena Villalonga, made to share in my blog. I was interested in knowing which oil is beneficial for our health and which one could be harmful so here is a summary of what you should consider when buying oil for cooking.

It is known that the Mediterranean diet is one of the healthiest in the world and this is partly due to the oil they use, the olive oil, in particular the extra virgin (EVOO) considering its benefits on health. Among some of its benefits we can mention reducing cardiac risk because it contains monounsaturated fats and oleic acid. It also contains antioxidants and other anti-inflammatory nutrients that help reduce levels of bad cholesterol (LDL), fight free radicals and prevent premature aging.

In the last few years the most commonly found oils in products such as biscuits, cereals, snacks, are rapeseed oil and palm oil, mostly boosted by the economic crisis because they are cheaper.

Conventional rapeseed produces an oil with a very high content of erucic acid. Since 1949 it is known that this fatty acid may be harmful for health, as it contributes to the formation of fatty deposits in the heart. Canola is a variety of rapeseed low erucic acid and is currently used for rapeseed oil for food use. It is a very healthy source of vitamin A, contains 29% of unsaturated fatty acids and, together with bluefish, it is one of the foods with higher intake of linoleic acid, known as Omega 3. It is ideal for frying given its low water content. It is also a product widely consumed in Canada. However, in Spain it continues to arouse suspicion as an unfortunate event occurred in 1981 while producing this oil in a factory and killed 1,100 people.

Regarding palm oil it is the most used oil in the world for food processing, ahead of soybean or rapeseed, being more economical. But this oil is rich in saturated fatty acids (over 50%) so it is far from being a suitable alternative from the point of view of nutritional balance because if consumed too often may stimulate the increased risk of cardiovascular diseases.

Another oil that can be found in food is Coconut oil, which is extracted by pressing the flesh of coconuts. Its oil contains about 90% saturated fatty acids, so many health organizations advise not to consume too much, because it has the potential to increase the risk of cardiovascular disease (OMS, 2015). On the other hand we must keep in mind that is a very aromatic oil when used raw. However, for cooking, such as frying, it does not provide enough flavor or taste to mask the main ingredients, as it is poorly absorbed.

I found more information about Coconut oil in the website ¨Dr Joanna¨.

In the kitchen you can also find Sunflower oil. From a nutritional point of view this oil is interesting for its high linoleic acid content (over 60%) and oleic acid (over 20%), healthy oils. Together with olive oil, sunflower oil stands out for its richness in vitamin E, a natural antioxidant that helps protect our body from the action of free radicals, which action is relevant in degenerative diseases and cancer.

Lastly we’ll refer to Corn oil. It is of great nutritional interest because it is very rich in polyunsaturated fatty acids (over 50% is linoleic acid) and vitamin E (a powerful antioxidant). It is used for the production of margarines and mayonnaises.

An important thing to consider is related to the process of frying or cooking with oil at high temperatures (greater than 180 Cº) since there is a change in the molecular structures of fats containing oils. In the case of the oils which are rich in polyunsaturated fats, such as corn oil or sunflower oil, high levels of aldehydes are generated, which are unhealthy. In contrast, in olive, coconut and rapeseed oils less aldehydes are generated as these oils are rich in saturated and monounsaturated fatty acids, being much more stable when heated.

Specifically, fried food with extra virgin olive oil  (EVOO), keep better nutritional properties than other methods such as boiling, as shown by a study from the University of Granada, although it will provide more fat and calories, but always less than seed oils since these ones have lower density and will penetrate more into the food provoking a higher caloric intake. In addition, the EVOO provide more polyphenols (natural antioxidants).

Based on the results of numerous research studies about the effects of the oils in our health containing healthy fats, particularly monounsaturated and unhealthy fats like saturated fat you could say that the EVOO is heading the consumption followed by rapeseed oil, maize and sunflower (see Table 1 below).

Currently, olive oil is the oil that is considered more beneficial to our diet and is also the one with more research and sustainability. Numerous scientific papers have been published regarding the value of the healthy properties of EVOO, particularly in diseases such as cancer which has been shown for instance that have a protective effect against breast cancer (Hydroxytyrosol Protects against oxidative DNA damage in human breast cells. F Warleta, CS Quesada, M Campos, and Allouche, G Beltran, JJ Gaforio. Nutrients 3 (10), 839-857)

Needless to say you have to be moderate with oil consumption and keep a balanced diet.

Below you will find the oils order by the healthiest one starting from the top.

Oils Saturated Monounsaturated Polyunsaturated
EVOO 14 73 11
Rapeseed 7 65 26
Corn 13 28 55
Sunflower 11,9 20 63
Palm 49 37 9
Coconut 86,5 5,8 1,8

Table Content: Fat content in grams/ 100 gr total fat. Healthy fats: Monounsaturated and Polyunsaturated. I

Source: OCU (Organization of Consumers and Users of Spain), Spanish Association nutrition and FDA (Food and Drug Administration).

Ximena Villalonga