Diet and Cancer Prevention Research: From Mechanism to Implementation.

Between 30% to 50% of cancer cases are estimated to be preventable through reduced exposure to tobacco, occupational carcinogens, and infectious agents, and adoption of lifelong healthy eating and a physically active lifestyle. In the past, diet and cancer prevention research has aimed to understand the effects of specific foods and nutrients on cancer-related mechanisms. More recently, there has been a shift in emphasis toward a more holistic focus on patterns of diet, reflecting the goal to understand the impact of adhering to broader public health recommendations. It is increasingly apparent from observational studies that different patterns of diet and physical activity are manifest in a metabolic state that is more, or less, conducive to the acquisition of genetic and epigenetic alterations leading to carcinogenesis. Experimental studies in cell systems, animals and humans have expanded our understanding of the many mechanisms by which specific dietary constituents may modulate inflammation and immune function, carcinogen metabolism, hormone and growth-factor regulation, DNA repair capacity, cell-cycle control, and proliferation and apoptosis. However, few mechanistic studies in animal models have evaluated diets containing the complex mixtures that make up human diets. Overall, more studies are needed across the continuum of prevention research, from basic mechanistic research on the effects of diet patterns on fundamental biologic processes to studies testing the efficacy of implementing lifestyle-directed cancer prevention strategies.