EFFECTS OF LACTITOL-OLIGOSACCHARIDES ON CALCIUM AND MAGNESIUM ABSORPTION IN RATS

Lactitol-oligosaccharide (LO) was prepared. from lactitol by transglyc osylation reaction with Aspergillus oryzae beta-galactosidase. LO is r esistant to metabolism in the small intestine but not in the large int estine. The effects of LO, lactose (Lac), lactitol (Lacol) and galacto -oligosaccharide (GL) on calcium and magnesium absorption were determi ned by feeding 8-week-old Sprague-Dawley male rats diets containing 5% of the above carbohydrates for two weeks. The results obtained were a s follows. 1) A significant increase of calcium absorption was observe d in the LO diet. 2) A significant increase of magnesium absorption wa s observed in the LO, GL and Lacol diets. 3) The concentration of tota l volatile fatty acids (VFA) in the cecal contents increased significa ntly in the LO, GL and Lacol diets. The main constituent of VFA in the cecal contents was found to be acetic acid. 4) The correlations betwe en calcium and magnesium absorption ratios and total VFA concentration in the cecum were found to be significantly related. These findings s uggest that LO is metabolized to VFA, among which acetic acid concentr ation seems to have the most stimulatory effect on the absorption of c alcium.