Mediterranean diet and cancer risk

Abstract

Various aspects of the Mediterranean diet are considered favourable with regard to cancer risk. These aspects were analysed using data from a series of case-control studies conducted in northern Italy between 1983 and 2001 on over 12,000 cases of 20 cancer sites and 10,000 controls. For most epithelial cancers, the risk decreased with increasing vegetable and fruit consumption, with odds ratios (OR) between 0.3 and 0.7 for the highest versus the lowest tertile. Subjects reporting frequent red meat intake showed ORs above unity for several common neoplasms. Conversely, fish (and consequently, n-3 fatty acids) tended to be another favourable dietary indicator. Wholegrain food intake was related to reduced risk of several types of cancer, particularly of the upper digestive tract, probably on account of its high fibre content. Fibres were in fact found to be protective with regard to colorectal and other selected cancers. In contrast to wholegrain, refined grain intake, and consequently glycaemic load, was associated with an increased risk of different types of cancer, including those of the upper digestive tract, colorectum, breast and endometrium. These results thus suggest that a low-risk diet for cancer entails increasing vegetables and fruit, reducing meat, but also refined carbohydrate consumption. Furthermore, olive oil and other unsaturated fats, which may be a unique common characteristic of the Mediterranean diet, should be preferred to animal and saturated fats. A score summarizing the major characteristics of the Mediterranean diet was inversely and consistently related to the risk of selected cancer sites. Regular consumption of pizza, one of the most typical Italian foods, showed a reduced risk of digestive tract cancers. Pizza could however simply be an indicator of a typical Italian diet.