EFFECT OF RESISTANT AND DIGESTIBLE STARCH ON INTESTINAL-ABSORPTION OFCALCIUM, IRON, AND ZINC IN INFANT PIGS

The first nonmilk foods that are given to infants contain high levels of starch, a fraction of which is resistant to enzyme hydrolysis. Inco mplete digestion of starch may interfere with the absorption of certai n minerals, A fraction of dietary starch which is resistant to in vitr o enzymatic hydrolysis has been termed resistant starch. The aim of th is study was to compare the intestinal apparent absorption of calcium, phosphorus, iron, and zinc in the presence of either resistant or dig estible starch. Twelve 7-10-d-old piglets were fitted with a T-tube in serted into the intestine approximately 3 m distal to the duodenum. An imals received in random order 200 mL of a test meal of cooked, cooled , high amylose corn starch (16.4% resistant starch), or cooked rice st arch (digestible starch) administered by an orogastric tube. Both meal s contained the same amount of calcium, phosphorus, iron, and zinc. Th e test meal also contained tracer amounts of Fe-59 and Zn-65, as well as polyethylene glycol 3350, as a nonabsorbable marker. Intestinal app arent absorption of starch was greater after the meal with digestible starch (71.0 +/- 17.0%) than after the meal with resistant starch (49. 2 +/- 10.3) (p < 0.001), After feeding the meals with resistant and di gestible starch, mineral apparent absorption was, respectively: calciu m, 40.2 +/- 11.8% versus 28.1 +/- 16.4% (p < 0.05); phosphorus, 73.2 /- 14.0% versus 67.8 +/- 18% (NS); iron, 24.1 +/- 12.2% versus 12.6 +/ - 10.6% (p < 0.01), and zinc, 35.0 +/- 13.0% versus 30.6 +/- 8.22% (NS ). In conclusion, a meal containing 16.4% resistant starch resulted in a greater apparent absorption of calcium and iron compared with a com pletely digestible starch meal. If this finding holds true for the who le bowel, administration of resistant starches could have a positive e ffect on intestinal calcium and iron absorption.