Abstract
Previously, we observed the inhibitory effect of phosphorylated oligosaccharides (PO) from potatostarch on the formation of calcium phosphate precipitate. PO were composed of two fractions: PO-1 and PO-2. The former was maltooligosaccharide bound to one phosphate molecule, and the latter was maltooligosaccharide bound to at least two phosphate molecules. PO-2 had a stronger inhibitory effect. In the present study, we investigated the effect of PO-2 feeding on calcium utilization in rats. Five-week-old rats were fed a calcium diet (0.52% of calcium) containing 5% PO-2 for two weeks. The apparent calcium absorption ratio and apparent retention ratio during two periods (days 3-6, days 10-14) were significantly lower in the rats fed the PO-2 diet than in those fed the control diet. The results of a breaking-force test and the calcium content of the femur did not differ significantly between the two groups. Whole cecal weight was significantly higher in the rats fed the PO-2 diet, and the amounts of short-chain fatty acid in the cecal content were significantly increased; cecal pH was not changed. There was no apparent correlation between the calcium-solubilizing effect of PO-2 in vitro and the degree of calcium absorption in vivo.
