Urine sugar concentrations will be determined by high-pressure liquid chromatography. Sucrose in 0-5-h urine, lactulose/rhamnose (L/R) ratio in 0-5-h urine, and sucralose/erythritol (S/E) ratio in 5-24-h urine will be used as indicators for gastroduodenal, small and large intestine permeability, respectively.