Location: Children's Nutrition Research CenterTitle: Slowly digestible starch diets alter proximal glucosidase activity and glucose absorption Author
|Fraley, J Ken|
Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 4/6/2010
Publication Date: 4/6/2010
Citation: Yan, L., Avery, S.E., Chacko, S.K., Fraley, J., Vohra, F., Nichols, B.L., Hamaker, B.R. 2010. Slowly digestible starch diets alter proximal glucosidase activity and glucose absorption [abstract]. Journal of Federation of American Societies for Experimental Biology. 24:231.4. Interpretive Summary:
Technical Abstract: Sucrase-isomaltase (Si) and maltase-glucoamylase (Mgam) are mucosal glucosidases required for digestion of starch to glucose. Ablation of maltase-Mgam reduces in vivo starch digestion. We tested whether slowly digestible starch diets induce changes in glucosidase activities. Rice starch was encapsulated in alginate microspheres to target small intestinal sites of starch digestion. Three groups of eight 8-wk old mice were given a maize 13C-starch test feed. Then they were fed rice maltodextrin, 0.5% rice starch microspheres, or 1% rice starch microspheres diets for 7 d, and a second maize 13C-starch test feed. Blood 13C-glucose produced from fed maize 13C-starch was measured by GC-MS. Activities of sucrase, maltase, and glucoamylase were measured by Dahlqvist assays. Absorption of glucose from 13C-starch was suppressed by feeding slowly digestible starch diets (ANOVA 0.000). Correlation was found between jejunal Si and Mgam activities and glucose absorption from 13C-starch (R2 0.64, 0.67). Jejunal Si and Mgam activities were correlated (R2 0.74). From this study we concluded that slowly digestible starch diets down-regulate jejunal Mgam and Si activities, and negative feedback on Si and Mgam activities regulates subsequent absorption of glucose from starch.