Effect of dietary fiber on azoxymethane-induced intestinal carcinogenesis in rats.
The effect of alfalfa, bran, and cellulose on intestinal tumor formation and fecal billary steroid levels was studied in male Sprague-Dawley rats given injections of azoxymethane (AOM). Animals received weekly injections of 8 mg AOM/kg and were fed diets containing 10% fiber (wt/wt) and 35% beef fat or 20 or 30% fiber and about 6% beef fat. Control animals in each instance were fed fiber-free diets. The addition of 10% fiber to the high-fat diet did not significantly reduce the intestinal tumor frequency (average No. of tumors/rat). However, addition of 20 or 30% fiber to the 6% fat diet significantly reduced the intestinal tumor frequency. The concentration of fecal biliary steroids (mg/g dry feces) was significantly lowered in the groups with reduced tumor frequencies, whereas the total excretion of fecal biliary steroids (mg/day) did not show a similar correlation. These observations suggest that intestinal tumor frequency can be reduced by increased dietary fiber only when fat intake is not at a high level. The effect of fiber may be due to dilution of promoters and/or carcinogens in the intestinal tract.
D000818:Animals; D001391:Azo Compounds; D001397:Azoxymethane; D001647:Bile Acids and Salts / Q000032:analysis; D001835:Body Weight; D002482:Cellulose; D002777:Cholestanols / Q000032:analysis; D004041:Dietary Fats / Q000008:administration & dosage; D004043:Dietary Fiber; D002149:Energy Intake; D005243:Feces / Q000032:analysis; D007414:Intestinal Neoplasms / Q000209:etiology* / Q000517:prevention & control; D008297:Male; D009374:Neoplasms, Experimental / Q000209:etiology; D051381:Rats
D001391:Azo Compounds; D001647:Bile Acids and Salts; D002777:Cholestanols; D004041:Dietary Fats; D004043:Dietary Fiber; D002482:Cellulose; D001397:Azoxymethane