PROTECTIVE EFFECTS OF HARD RED VERSUS HARD WHITE WINTER WHEATS IN CHEMICALLY-INDUCED COLON-CANCER IN CF1 MICE

The relative protective effects of hard red versus hard white winter w heats in 1,2-dimethylhydrazine-induced colon cancer in CF1 mice were c ompared, and the effects of both whole wheats were compared with that of cellulose. Animals (50 per group) fed red wheat diets containing th e whole wheat, bran, or endosperm had lower incidence of tumor develop ment than those fed respective white wheat diets. Tumor incidence in a nimals fed a synthetic diet containing cellulose was not different fro m those fed the whole wheat diets containing similar amounts of insolu ble dietary fiber. However, the number of tumors per tumor-bearing ani mal (multiplicity) was significantly lower in animals fed red whole wh eat than it was in those fed the cellulose diet. Only animals fed the red bran diet had tumor incidence lower than that of the cellulose-fed animals. The tumors were located in the lower one-third of the colon; no metastasis to local lymph nodes and other tissues had occurred. Co lon tumor incidence was weakly and inversely correlated with insoluble dietary fiber (r = -0.2477, P = 0.1050), total dietary fiber (r = -0. 2489, P = 0.1033), and phytic acid (r = -0.2327, P = 0.1285) in the di ets. Total phenolic compounds and vitamin E were higher in the red whe at than they were in the white wheat. The total amount of fecal neutra l sterols excreted per day was significantly higher for animals fed re d bran diet than it was for animals fed any other diet. There were no significant differences in excreted bile acid amounts between animals fed any white versus red wheat diets. Data suggest that no single fact or measured plays a major role in protecting against chemically induce d colon cancer in mice, but all of those factors may exert some antitu mor effect.