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 13C-starch-based materials differing in digestion rates (fast, slow, and slower), and then given a digestible 13C-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 (R2 = 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.
Keywords: Dietary approach; Glucose absorption; Glycemia; Slowly digestible starch; α-glucosidases.
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