THE ROLE OF OLIVE OIL AS A FUNCTIONAL FOOD ON HUMAN HEALTH

摘要

Olive oil, an integral component of the Mediterranean - Cretan diet, is the primary source of fat in the diet of the populations surrounding the Mediterranean Sea. An increasing interest has been observed in discovering the olive oil's functional role. The consumption of olive oil has potential effects on human health because of its chemical composition, which includes components showing a high bioactivity and bioavailability. The pharmacological potential of olive oil, beyond its nutritional value, has been largely attributed both to its high content of monounsaturated fatty acids (MUFA) (especially oleic acid) and to its content of other minor components with biological properties. A Mediterranean diet, rich in oleic acid, has been shown to beneficially affect lipidemic profile of humans besides showing its antiatherogenic and antithrombotic effects. The phenolic content of olive oil (oleuropein, tyrosol, hydroxytyrosol) has presented antioxidant, anti-inflammatory and antiatherogenic action in vivo. Some other minor compounds like the carbohydrate squalene and the sterol P-sitosterol, have been associated with protective properties against cancer. Although the tocopherol (a-tocopherol, carotenoids) content of olive oil is low, it augments the overall antioxidant content in the human body. According to recent scientific data, the synergistic effect of the above constituents has been associated with a decreased factor of cardiovascular disease, type 2 diabetes, obesity, metabolic syndrome, cancer, oxidative stress and chronic degenerative diseases of nervous system (Parkinson's disease, Alzheimer's disease, age-related cognitive decline), leading to a healthier aging and increased longevity. Scientific studies taking place at countries like Greece, Spain and Italy, where the olive oil intake remains at high levels, confirm the facts above both at epidemiological and at cellular base. The improvement of lipidemic profile, the reduction of LDL susceptibility to oxidation, the improvement of endothellal function, the adjustment of blood pressure and the favorable modifications of hemostasis summarize the beneficial effect of olive oil consumption against cardiovascular disease. The functional effect of olive oil on diabetes is revealed not only by increasing the organism's insulin sensitivity but also by adjusting the glucose and postprandial lipemia levels after meals. Increasing evidence suggests that pathological conditions, related to diabetes, like obesity or/and metabolic syndrome (MetS) are beneficially affected by a diet rich in olive oil. Modulations on the initiation, promotion and histopathological malignancy of tumors suggest the potential protective effect of olive oil on cancer. Such protective action on cancer may be mediated through the constituents showing anticancer properties together with the adoption of healthier dietary habits. At last, the beneficial effect of dietary olive oil on oxidation and as a result the beneficial effect on the initiation and progress of age-related chronic degenerative diseases of nervous system, is exclusively attributed to its antioxidant content, which manages to bind the free radicals in the human body. Olive oil, as a functional food maximizes its health benefits on a healthy dietary pattern basis.