MODIFICATION OF AZOXYMETHANE INTESTINAL CARCINOGENESIS IN RATS BY FEEDING SUCROSE BOLUSES, PASTA, AND GLUCOSE

We studied whether repented boluses of sucrose or diets containing car bohydrates with a variable glycemic index (GI) affect intestinal carci nogenesis in rats. Male F344 rats were treated twice (1 wk apart) with 15 mg/kg sc azoxymethane (AOM) and then divided into four experimenta l dietary groups with different carbohydrate composition and administr ation schedules: the sucrose group was fed 44% (wt/wt) sucrose (GI = 6 5), the bolus group was fed sucrose as carbohydrate and 43 boluses of sucrose (10-15 g/kg) at various time intervals, the pasta group was fe d pasta [77% (wt/wt) cooked pasta, GI = 55], and the glucose group was fed 44% (wt/wt) glucose (GI = 97). All nutrients, including carbohydr ates, were provided in similar amount to the different groups. The exp eriment was terminated between Day 230 and Day 245 after AOM administr ation. At this rime the pasta group had significantly higher cecal sho rt-chain fatty acids than the other groups. Intestinal adenomas and ca ncers occurred with the same frequency in the bolus, sucrose, and gluc ose groups. On the contrary, we observed a significant decrease (p = 0 .03) in the cumulative incidence of intestinal adenomas, but nor adeno carcinomas, in the pasta group compared with the sucrose group (intest inal adenoma incidence in the pasta group was 31% compared with 63% in the sucrose group, 46% in the bolus group, and 37% in the glucose gro up). In conclusion these results do not support the hypothesis that su crose boluses or carbohydrates with a high GI stimulate colon carcinog enesis, but they indicate that foods such as pasta may exert a protect ive effect.