The Mediterranean diet not only produces favourable effects on blood lipids but also protects against oxidative stress. Oxidative damage is thought to represent one of the mechanisms leading to chronic diseases such as atherosclerosis and cancer. Many studies suggest that a link exists between fruit and vegetables in the diet or the amounts of plasma antioxidant vitamins (ascorbic acid, tocopherol and carotenoids) and risk of death from cancer or coronary heart diseases. Although a large emphasis has been given to different components of the diet, attention has recently shifted to the diet as a whole. The Mediterranean diet is able to modulate oxidative stress through complex mechanisms and not just the high antioxidant compound content. The preference for fresh fruit and vegetables in the Mediterranean diet will result in a higher consumption of raw foods, a lower production of cooking-related oxidants and a consequent decreased waste of nutritional and endogenous antioxidants. The high intake of antioxidant and fibre helps to scavenge even the small amount of oxidants or oxidized compounds.

Dietary recommendations evolved from instructions directed at prevention of starvation diseases to the level of intake of essential nutrients that are adequate to meet the known nutrient needs of practically all healthy persons. Vitamin requirements have been modified various times over the years and there are still differences in recommended intakes in different countries. A debate on optimal vitamin intake is ongoing, based on the concepts of deficiency, sufficiency and hypothetical identification of a range within which a further biological advantage can be expected. In establishing appropriate criteria for food and nutrient intakes, additional studies are warranted on the physiological interactions between nutrients and non-nutrients and on many other factors such as genetic determinants and lifestyle which could interfere with disease prevention.

Cancer is said to be due to nutrition in 35 cases out of 100, ranging from 10 to 70% by sites. Saturated fats show a positive relationship with cancer, while vitamins, vegetables and cereals show a negative relation with it. This work was aimed at studying the relationship between nutrition and cancer in different Italian areas. Cancer mortality rates collected in 94 National Health units over the period 1980-82 have been correlated with the average food consumption of individuals registered in the same units. All the nutrient groups have shown evidence of a correlation between nutrient intake and mortality rates. Fats, animal proteins and saturated fatty acids showed the strongest positive correlations; vegetable proteins, fibre, carbohydrates, oleic acid, vitamins C and B1 gave negative correlations. Thus, it can be concluded that (a) this ecological analysis has confirmed previous hypotheses concerning the role of vegetables in cancer prevention and (b) the relation between nutrition and cancer mortality could be even stronger if applied to the whole population, since a 1-g increase in vegetable protein consumption would result in a reduction of 2.5 cases out of 100, a 1-g increase in fibre would result in a reduction of four cases out of 100 and a 1-g increase in animal fat would result in an increase of one case out of 100.