Olive oil is the most representative food of the traditional Mediterranean Diet. Olive oil is a functional food which, besides having a high level of monounsaturated fatty acid (MUFA), contains several minor components with biological properties. Increasing evidence suggests that MUFA as a nutrient, Olive Oil as as a food, and the Mediterranean Diet as a food pattern are associated with a decreased risk of cardiovascular disease, obesity, metabolic syndrome, type 2 diabetes and hypertension.

The best studied minor components of olive oil are its phenolic compounds, commonly called “polyphenols” although the olive oil, besides polyphenols contains simple phenols. The content of the polyphenols of an olive oil varies, depending on the variety (Arbequina, Picual, Tsunami, etc) of the olive, type of  cultivar, climate, ripeness of the olives at harvesting, and the processing system for the type of olive oil. As a general rule, the polyphenol content of a virgin olive oil is higher than that present in a common or a pomace olive oil.

Results of the EUROLIVE study (www.kepka.org/eurolive), an European study in which 200 European healthy individuals ingested 25 mL/day of three types of similar olive oils but with low, medium, and  high phenolic content, during intervention periods of 3 weeks showed that:

• All types of olive oils can provide benefits for health in terms  of increasing the HDL cholesterol content (the “good cholesterol”) and  at the same time  reducing the effect of oxidative stress, a risk factor for cardiovascular, cancer, and neurodegenerative diseases, as well as ageing.
•The higher benefits for health, however, were achieved by consumption of olive oil with high phenolic content.
•Consumption of 25 mL/day of olive oil did not increase the weight of the participants. Of course these 25 mL/day should replace another kind of fat food, and not be consumed additionally.
•A single dose of 25 mL with bread did not promote postprandial (after meals) oxidative stress.

Therefore, the polyphenol content of an olive oil is an important factor for consumers to consider when selecting an olive oil. However, the polyphenol content influences the taste of an olive oil. Olive oils with high polyphenol content are stronger, and, in general bitter and greener than those with a low one. The taste of an olive oil is an important factor that influences consumers´ choice.

Olive oil must not be taken as a medicine, and never alone but as a part of meals. The Mediterranean diet, in which olive oil is the main source of fat, might prevent the incidence of cardiovascular cancer, and neurodegenerative disease disease, and also overall mortality. One important factor associated with the Mediterranean diet, and the Mediterranean way of life is: “to enjoy cooking and eating the meals”. Let us not forget that athletes of the Olympic games, in ancient Greece, based their nutrition on the Mediterranean diet.

It is commonly accepted that consumers, when purchasing an olive oil are interested in its quality, its taste, its colour, and its price, but they are also concerned about its safety and its impact on their health. Consumers´ choice is influenced by the cost/benefit ratio that is based on the above–mentioned characteristics of the olive oils.