Alterations in rat bone composition related to polyol supplementation of the diet

The effect of dietary supplements of xylitol, sorbitol and glucose on bone composition was studied in rats. The supplementation, expressed as a % of the dry diet, was gradually increased up to 20% over 3 weeks and continued for 5 weeks. The control group was fed a stock diet only. Each group consisted of nine rats aged 12 weeks at the beginning of the experiment. Ca, Mg, P, CO3 and citrate were analysed from the femur and Ca and citrate also from the serum and urine. The results showed that xylitol supplementation significantly increased the concentrations of Ca and citrate in bone (P less than 0.001) and sorbitol that of Ca only, whereas glucose slightly reduced both CO3 and citrate. The citrate concentration was found to correlate significantly with Ca and P (P less than 0.001), and also with Mg (P less than 0.002). Both xylitol and sorbitol increased serum Ca and the urinary excretion of Ca and citrate. In conclusion, high xylitol or sorbitol supplementation affects Ca and citrate metabolism. The results suggest a connection between citrate and Ca in bone.