Conditioning with slowly digestible starch diets in mice reduces jejunal α-glucosidase activity and glucogenesis from a digestible starch feeding.

Objectives: Maltase-glucoamylase (Mgam) and sucrase-isomaltase (Si) are mucosal α-glucosidases required for the digestion of starch to glucose. We hypothesized that a dietary approach to reduce Mgam and Si activities can reduce glucose generation and absorption, and improve glucose control.

Methods: Rice starch was entrapped in alginate microspheres to moderate in vitro digestion properties. Three groups of 8-wk old mice (n = 8) were conditioned for 7 d with low C-starch-based materials differing in digestion rates (fast, slow, and slower), and then given a digestible C-labeled cornstarch test feeding to determine its digestion to glucose.

Results: Conditioning of the small intestine with the slowly digestible starches for 7 d reduced jejunal α-glucosidase and sucrase activities, as well as glucose absorption for the slowly digestible starch slower group (P < 0.01). A correlative relationship was found between glucose absorption from a cornstarch test feeding given at d 7 and jejunal α-glucosidase and sucrase activities (R = 0.64; 0.67). However, total prandial glucose levels during the 2-h feeding period did not differ.

Conclusions: Decreased glucogenesis from a digestible starch feeding was found in mice conditioned on slowly digestible starch diets, suggesting that a dietary approach incorporating slowly digestible starches may change α-glucosidase activities to moderate glucose absorption rate.