Environmental dietary factors in colorectal cancer. Some unresolved issues

Abstract

Background: Unresolved epidemiologic issues in large bowel cancer include reasons for changes in incidence rates, differences in epidemiology of cancer in the distal and proximal colon and rectal cancer, and the optimal fat and fiber levels for low rates.

Methods: The authors examined questions of suitable procedures for the assessment of intake of specific key nutrients and mode of cooking. International data by site and nutritional factors were compared.

Results: Fat and fiber intake in the United States, Japan, and Finland related to differences in rates. Laboratory animal model studies indicated that type of fat affected carcinogenesis. Colon cancer rates in men in the United States increased slightly, but started to decline slightly, as in women.

Conclusions: Dietary factors play a key role in causation and prevention of large bowel cancer, with a diet of 25% fat and 25 g fiber recommended. Comprehensive school health education should be used to modify the nutritional habits of children.