gastrointestinal transit with fiber-containing.pdf

Am J C/in Nutr 1989;49:471-5. Printed in USA. ? 1989 American Society for Clinical Nutrition 471 Apparent nutrient absorption and upper gastrointestinal transit with fiber-containing enteral feedings13 Fred L Shinnick, RandailL Hess, Milton H Fischer, andfudith A Marleti ABSTRACF Uppergastrointestinal tract function in humans was investigated by studying the acute effects ofsupplementing enteral feedings with dietary fiber. Serum concentrations of folate, zinc, and glucose were determined at timed intervals for 4 h after ingestion of nutrition- ally complete liquid meals containing test doses offolate and Zn oftwo and six times the RDA, respectively, with or without addition of 10 or 15 g of soy polysaccharide fiber. Mouth-to- cecum transit time was determined by measuring breath hydrogen produced from lactulose added to the meals. Both levels of fiber significantly lengthened transit time. Serum folate concentrations were significantly lower from 45 to 150 mm after one or both fiber-containing meals relative to the fiber-free meal. Only the higher-fiber meal significantly lowered serum Zn concentrations. This study demonstrated that dietary fiber can decrease apparent nutrient absorption and increase transit time in the upper gastrointestinal tract without affecting appar- ent glucose absorption. Am J C/in Nuir 1989;49:471-5. KEY WORDS Serum glucose, serum zinc, serum folate, complete liquid meals, enteral nutrition, nutrient interaction, mouth-to-cecum transit time, breath hydrogen Infroduction Soy polysaccharide is one ofthe fiber sources that has been used to supplement enteral feeding products to im- prove bowel function. However, in comparison with other fibers, it has only a moderate effect on large-bowel function (1, 2). As reviewed recently by Cummings, soy fiber has only halfthe effect ofwheat bran on stool weight when comparable amounts are ingested (3). As measured by apparent glucose absorption, soy polysaccharide has little effect on small-bowel functi