Cancer chemoprevention by nuts: evidence and promises.

Chemoprevention is the use of chemical compounds to interfere with the early precancerous stages of carcinogenesis and thereby reverse tumor formation. Many chemopreventive agents, either natural or synthetic, have been identified. Some of the most promising compounds are found in vegetables and fruits. There are numerous mechanisms of action by which these components can intervene in the prevention of cancer, although they have not been fully elucidated. It is worth to note that some foods contain different bioactive compounds. Therefore the possibility exists that combinations of compounds, naturally occurring in those foods, may have a cumulative or even synergistic effect. Nuts are very rich in different bioactive compounds whose anti-cancer properties have already been described. Epidemiologic studies have already suggested that nuts consumption may be potentially beneficial in the incidence of other diseases, such as coronary heart disease and diabetes. Although the results are not conclusive, recent studies show possible cancer protective effects of nuts. This review will focus on the laboratory and clinical evidence of nuts chemopreventive and therapeutic properties.