The effects of a "low-risk" diet on cell proliferation and enzymatic parameters of preneoplastic rat colon.

The relationship between various dietary constituents and colon cancer has been demonstrated by previous research. This study was conducted to investigate the combined effects of several dietary constituents on the preneoplastic stage of azoxymethane (AOM)-induced colon cancer in rats. A nutritionally adequate, "low-risk" (LR) diet was formulated through the modulation of dietary fat, fiber, protein, vitamins A and E, and selenium. Female F344 rats were given three weekly subcutaneous injections of AOM and were maintained on either the LR diet or a "high-risk" (HR) diet. After 12 weeks, the rats were killed and the following parameters were determined: pH of colon contents, fecal beta-glucuronidase activity, tissue ornithine decarboxylase (ODC) activity, and colonic labeling index. The pH of the colon contents and incremental labeling index were lower in the group given the LR diet and treated with AOM compared with the group given the HR diet and treated with AOM; however, no statistically significant dietary effects were observed for beta-glucuronidase and ODC activities. The results of this study indicated that the colons of rats fed the LR diet exhibited different proliferative characteristics than did the colons of rats fed the HR diet.