Maltitol-induced increase of transepithelial transport of calcium in rat small intestine.

To gain an insight into a mechanism whereby maltitol increases intestinal absorption of calcium, we evaluated transepithelial calcium transport of everted segments of rat small intestine by comparing the values in the presence of maltitol with the values in the presence of maltose. In jejunal segments, no significant difference in the rate of calcium transport was seen between the incubations in the medium containing 100 mM maltitol and in the medium containing 100 mM maltose, regardless of the calcium concentrations in the mucosal-side medium. By contrast, the everted ileal segments incubated in the presence of maltitol exhibited two-fold greater transepithelial calcium transport than did the segments incubated in the presence of maltose at a high (10 mM) concentration of calcium, whereas at a low (0.5 mM) concentration of calcium, maltitol did not produce a significant effect. With the conditions in which intestinal alpha-glucosidases were inhibited using the medium containing Tris or acarbose, a slight (40%) but significant increase of calcium transport was again observed in the segments incubated in the medium containing maltitol as compared with the medium containing maltose. The results suggest that maltitol enhances the rate of transepithelial calcium transport in the lower part of small intestine by modulating the passive diffusion of calcium, and that not only the nature of low digestibility, but also some other nature(s) of maltitol might be responsible for the maltitol-induced increase of ileal calcium transport.