Improving the palatability of oral rehydration solutions has implications for salt and water transport: a study in animal models.

It is believed that improving the taste of oral rehydration solutions (ORSs) might lead to greater patient acceptability. A pilot trial showed that replacing glucose with sucrose and increasing the citrate concentration at the expense of chloride improves palatability. However, the transport implications of such modifications are not known. Three hypotonic experimental ORSs (Suc/cit-ORS, 211 mosmol/kg; Suc/Cl-ORS, 224 mosmol/kg; and Glu-ORS, 224 mosmol/kg) were compared with a standard European ORS (Euro-ORS, 265 mosmol/kg) by in vivo perfusion of entire rat small intestine in normal adult rats and rotavirus-infected neonates. All ORSs were of identical sodium, potassium, chloride, and citrate content except that in the Suc/cit-ORS, chloride was removed in favor of increased citrate, and the chloride concentration in Euro-ORS was higher than in the others. Suc/cit-ORS and Suc/Cl-ORS had glucose partially replaced by sucrose while Glu-ORS and Euro-ORS contained only glucose. In normal small intestine, water absorption was greater from Glu-ORS than Suc/cit-ORS or Euro-ORS, although water absorption was similar from Suc/cit-ORS and Suc/Cl-ORS. In the rotavirus model, Glu-ORS produced more water absorption than Euro-ORS or either sucrose ORS. In both models, Suc/cit-ORS caused sodium and chloride secretion. Glucose absorption was similar from all ORSs. These findings indicate that attempts to improve ORS palatability by adding sucrose or increasing citrate at the expense of chloride would incur a significant penalty in terms of salt and water absorption.