In the Mediterranean contries, olive oil is one of the major constituents of the diet. Consumption of olives or olive oil is considered important for preserving a healthy and relatively disease-free population. Epidemiologic data show that the Mediterranean diet has significant protective effects against cancer and coronary heart disease. They present evidence that it is the unique profile of the phenolic fraction, along with high intakes of squalene and the monounsaturated fatty acid oleic acid, that provides the health-protecting properties in olive oil. High consumption of extra-virgin olive oils, which are particularly rich in phenolic antioxidants, ie hydroxytyrosol, tyrosol, oleuropein, lignans, as well as squalene and oleic acid, should afford considerable protection against cancer (colon, breast, skin), coronary heart disease and ageing by inhibiting oxidative stress (Owen et al, 2000). The largest producers of olive oil in the world are Spain, Italy, Greece, Portugal and Turkey. Olive oil is an important constituent of the diet in Turkey, the second largest olive producer and fourth largest olive oil producer in the world. The annual per capita olive oil consumption is around 0.45 kg in USA and 0.02 kg in Japan, but 1 kg in Turkey (OPS). The incidence of cancer overall in Mediterranean countries is lower than in Scandinavian countries, the UK and the USA. This is mostly accounted for by the lower incidence of cancer of the large bowel, breast, endometrium and prostate, having a pathogenetic role of free radicals (Trichopoulou et al, 2000). The phenolic fraction of olive oil confers its health-promoting properties by the route of antioxidant activity. The major phenolic compounds are simple phenols (hydroxytyrosol, tyrosol), secoiridoids (oleuropein) and the lignans. These antioxidants present in olive oil are able to scavenge free radicals and afford adequate protection against peroxidation (Owen et al, 2000). The colorectal and prostate cancer incidences are 4 and 6.3% in men and breast cancer incidence is 14.9% in women in Turkey. These values are higher in USA 10.8, 36 and 31.7% respectively (Firat & Celik, 1998). Although increased use and improved techniques for detection of prostate, breast and colorectal cancers are resulting in larger numbers of these cancers being detected at early stages when they are more readily treatable, they are the leading cancers in overall cancer mortality in the USA. We believe that the olive oil and cancer risk relationship not only provides further data in the scope for future clinical studies in prevention of carcinogenesis, but also offers development of new strategies by public health planners and governments, especially in well-developed Western countries with relatively low olive oil consumption. Also, we conclude that, when compared to the high amount of olive production, consumption of olive oil is relatively low in Turkey compared with per capita annum consumption of around 10–12 kg in Italy and Spain. As a Mediterranean country we should also increase our olive oil consumption in the future. In conclusion, if the population in developed Western countries shifted to the traditional healthy Mediterranean diet, the incidences of these malignancies may decrease.
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Chemistry of Natural Compounds (2011)