LIMITED EFFECT OF CONSUMPTION OF UNCOOKED (RS2) OR RETROGRADED (RS3) RESISTANT STARCH ON PUTATIVE RISK-FACTORS FOR COLON-CANCER IN HEALTHY-MEN

To investigate whether resistant starch (RS) affects putative risk fac tors for colon cancer, 24 healthy men consumed a daily RS supplement f or 4 wk in addition to their habitual diet in a single-blind, randomiz ed, balanced multiple crossover trial. During the first week, all subj ects consumed the control supplement containing glucose. Subsequently, each subject consumed, in random order, a supplement with RS, (uncook ed high-amylose cornstarch), RS3, (extruded and retrograded high-amylo se cornstarch), and glucose, each for 1 wk. The RS2 and RS3 supplement s provided 32 g RS/d. Lithium was added to the supplements to measure compliance. Feces, 24-h urine, and breath samples, as well as a 24-h f ood-consumption recall were obtained weekly from each subject. Complia nce as measured by urinary lithium recovery was satisfactory. The mean composition of the background diet did not differ between the various supplementation periods. Breath-hydrogen excretion, stool weight, and fecal starch excretion were significantly higher during RS than durin g glucose supplementation, but did not differ during RS, and RS, suppl ementation. There were no significant differences in fecal dry weight, pH, or short-chain fatty acid concentrations, nor in the pH, bile aci d concentrations, cytotoxicity, or osmolality of fecal water. It is co ncluded that in healthy men, supplementing the habitual diet for 1 wk with 32 g RS2 or RS3/d compared with glucose had no effect on putative risk factors for colon cancer, except for increasing stool weight and colonic fermentative activity. There were no significant differences between the effects of RS2 and RS, on the indexes studied.