The role of nutrition in cancer development and prevention.

Nutrition has long been suspected to play an important role in cancer etiology. The biologic properties of nutrients make them prime candidates to aid in cancer prevention. Indeed, early epidemiologic cancer studies seemed to confirm the relevance of diet. These studies, however, were plagued by recall bias and confounding and may have thus been misleading. The results from large, prospective cohorts do not support a strong relation between nutrition and cancer. Given the difficulties in precisely assessing habitual diet, modest associations may exist, which may be impossible to capture when relying on self-reported dietary information. Energy balance, reflected in a low body weight and high level of physical activity, has been more convincingly related to lower cancer rates. The potential importance of more extreme dietary regimens and of nutrition during earlier periods of life remains to be explored. Finally, epigenetic research is likely to contribute to the understanding of nutritional regulation of gene expression. (c) 2004 Wiley-Liss, Inc.