Understanding the association between diet and nutrition in upper gastrointestinal cancer.

Human vulnerability to cancers of the upper gastrointestinal tract is strongly influenced by environmental factors. The esophagus, in particular, is highly vulnerable to the combined effects of exposure to environmental carcinogens and malnutrition, particularly in certain extreme environments of the developing world. Even in high-income countries, dietary carcinogens and nutrition play a major role in the etiology of oropharyngeal, esophageal and, to a lesser extent, gastric cancers, but the mechanisms are poorly understood. A thorough understanding of the biological mechanisms underlying the vulnerability of these organs to neoplasia would shed further light on the etiology of upper gastrointestinal cancers in all environments. In the meantime, the epidemiological evidence suggests that the risks can be minimized by dietary patterns that adhere closely to current public health recommendations, coupled with maintenance of body mass index within the healthy range.