[Effect of nutrition factors on the pathogenesis of colorectal carcinoma]

There is convincing evidence that nutrition affects colorectal carcinogenesis in a complex fashion. Dietary components either promote or inhibit the carcinogenic process. The composition of dietary fats seems to be less important as a promoting factor than a positive energy balance, especially in combination with low physical activity. Excessive consumption of red meat is associated with increased risk, which may be due to the heme contained in myoglobin. Alcohol stimulates cell proliferation in the rectum and may thus increase cancer risk. Complex carbohydrates (e.g., dietary fiber) are degraded in the colon to short-chain fatty acids which exhibit protective effects in experimental models of carcinogenesis. The putative protection from vitamins and trace elements merits further attention.