The Mediterranean diet was first considered to be a low-saturated fat diet that conveyed protection against coronary heart disease by lowering plasma total cholesterol levels. Later, the emphasis shifted away from the low-saturated-fat content of this diet toward its high content of olive oil and its overall constellation of characteristics. Moreover, there is now evidence that the Mediterranean diet benefits not only the risk for coronary heart disease but also cancer occurrence, total mortality, and longevity
In conclusion, there is considerable evidence that diet has an important role in cardiovascular epidemiology, and that an optimal diet for cardiovascular health has an extensive overlapping with the traditional Mediterranean diet. It has not yet been established which are the particular components or interactive processes in the Mediterranean diet that are responsible for its apparent health effects. There is evidence, however, that olive oil has beneficial properties and there is strong evidence that it is not possible to consume the large quantities of vegetables and legumes that Mediterraneans do in the absence of olive oil.