The advancements in the last six years derive from the extensive use of molecular approaches to perform research in the nutritional field. Moreover, the fundamental observation of R. Doll and R. Peto (1981), which suggested that at least 35% of all cancers (with large differences among different tumors) might be prevented by dietary regimens, has been confirmed by epidemiological studies. However, it is difficult to reduce them to simple terms - metabolic and hormonal factors, contaminants and biological agents, and deficiency of specific protective nutrients are all components of the same puzzle. In the 1990s a large number of compounds responsible for the biological activity of human foods have been identified and characterized. These molecules not only include important and well-known risk factors but, most promising, compounds, which might exert chemopreventive activity. Among them, antioxidants (such as vitamins, phenols, and lycopene) seem to play a critical role in reducing the risk of cancer at different anatomical sites, including colon, breast, and prostate malignancies.Other molecules, derived from fiber bacterial intestinal degradation (short fatty acids), are of interest, even if their importance has not been completely unravelled and is still the subject of debate. Data suggest that dietary-derived compounds, including radical scavengers, affect cell proliferation by acting on the cell division cycle engine and thus might control the process (and the rate) of malignant transformation.
