The Following Information has been provided by the International Olive Oil Council
Consumers have growing access to ever more comprehensive product information. Often this is supplied in publicity by the companies producing the product, in which case it is always subjective. Other times the sources are more objective, such as the media, reports by consumer organizations, and scientific or technical studies, although this last type of information takes longer to reach the general public. Consumers pay more attention to food products because the consequences they have can be beneficial or harmful to health.
Any information on olive oil would be incomplete if it did not take into account this important facet, especially when the beneficial effects of consuming olive oil are backed by lengthy, painstaking scientific research. The fat and oil sector is very complex. Fats and oils have a common denominator which is their energy value - 9 calories per gram - but the metabolism of each one or each group differs greatly from the rest. Olive oil contains a series of compounds that are very beneficial to most functions of the human body. Highly-qualified members of the scientific profession now discuss these on the basis of studies and experiments.
Olive oil's biological and therapeutic value is related in many aspects to its chemical structure. The first aspect is its triglyceride composition, made up of fatty acids. Olive oil has a prevalence (54 - 83%) of monounsaturated fat, oleic acid principally, while animal fats are fundamentally made up of saturated fatty acids and seed oils of polyunsaturated (50 - 72% in soybean and sunflower oil). Monounsaturated fatty acids are much more stable than polyunsaturated ones vis-à-vis the oxidative processes that, if produced, lead to rancidity. Olive oil also has a low percentage of polyunsaturated fats varying between 3.5 and 22.5%. These are essential fatty acids that cannot be synthesized by the body. However, a normal diet covers the essential fatty acid requirements of both adults and infants and has the best linoleic acid to linolenic acid ratio. Both olive oil and olive-pomace oil have an identical glyceridic structure, which means they share the same beneficial properties.
Secondly, olive oil's beneficial properties lie in its minor components. The most salient ones are the tocopherols, among them alpha-tocopherol which acts as vitamin E and carotene as provitamin A, and the polyphenols. All of these components have a major antioxidant function and are closely connected with virgin olive oils because refining processes alter and partially remove them in the other types.