Nutritional chemoprevention of colon cancer.

Abstract

Evidence emerging from many different types of experimental designs continues to support the concept that dietary habits, and nutritional status, play important roles in determining the risk of developing colorectal cancer. Overall, a diet habitually high in fresh fruits and vegetables, modest in calories and alcohol, and low in red meat and animal fat is cancer protective. This field of investigation is nevertheless very confusing, particularly because longstanding hypotheses, such as the presumed protective effects of fruits, vegetables, and fiber, have recently been challenged by well-designed prospective trials. The search for individual components in the diet that convey protection continues: calcium, folate, and selenium are the leading candidates in this regard. There is also growing interest in other plant-based compounds, so-called phytochemicals, although our understanding of their effects is quite rudimentary at present. However, regardless of the constituent components of the diet, evidence continues to accrue that ingesting a sensible amount of calories and maintaining a desirable weight also play important roles in prevention of this cancer. Although the inconsistencies in this field make it tempting to minimize its import, there is little question that diet has a major impact on colorectal cancer risk; diligent attention to the rigorous conduct of studies and their interpretation will likely clarify these relationships over the next decade, much to the benefit of public health.