EFFECT OF RESISTANT STARCH ON INTESTINAL RESPONSES IN RATS

Native starch (NS) extracted from wheat and subjected to five autoclaving and cooling cycles contained 11.5% resistant starch (RS), which was measured as insoluble fiber; NS contained a mere 0.5% RS. Both starches were fed to groups of rats for four weeks (RS was fed with or without antibiotics). Compared with rats fed NS, those fed treated starch showed a sixfold (RS diet) or nearly 18-fold (RS with antibiotics) increase in fecal wet weight; increases in fecal volumes paralleled increases in fecal weight. Rats fed treated starch (no antibiotics) digested 37.1% RS; those fed antibiotics digested only 14.3% RS. RS thus appears to be highly resistant to mammalian enzyme and may be classified as a component of fiber.