Dietary Regulation of Small-intestinal Disaccharidases

Abstract

Small-intestinal disaccharidases, including sucrase-isomaltase (S-I) and lactase-phlorizin hydrolase (LPH), are regulated by dietary nutrients at multiple steps of synthesis, post-translational modifications and degradation of S-I and LPH. These include 1) elevation of S-I mRNA and LPH mRNA levels induced by dietary carbohydrates, and 2) alteration of post-translational modification and/or enhancement of degradation of S-I and LPH caused by intake of diets rich in long-chain triglycerides or protein, due presumably to an increase in the luminal factors involved in degradation of disaccharidases on the microvillar membranes, e. g., bile acids and pancreatic proteinases. Thus, variation in the digestive-absorptive capability of carbohydrates in intestinal absorptive cells is determined not only by the adaptive response to dietary carbohydrates, but also modified by intake of other macronutrients, i. e., fat and protein.