DIMINISHED BONE-RESORPTION IN RATS AFTER ORAL XYLITOL ADMINISTRATION - A DOSE-RESPONSE STUDY

The effects of 5, 10, and 20% dietary xylitol supplementations on the resorption of bone were studied. The resorption was measured by the ur inary excretion of [H-3] radioactivity from [H-3] tetracycline-prelabe led rats. The 10 and 20% oral xylitol administrations caused a signifi cant decrease in the excretion of [H-3] as compared with the control g roup with no xylitol supplementation. The effect was detected as early as 2 days after the beginning of xylitol-feeding and was maintained t hroughout the experimental period of 31 days. The retarding effect on bone resorption was about 25% in the 10% xylitol group, about 40% in t he 20% xylitol group, and undetectable in the 5% xylitol group. The am ount of preserved [H-3] radioactivity in the tibiae of the 10 and 20% xylitol groups after the experiment clearly exceeded the values of the control group. The mechanism of the retarded bone resorption caused b y dietary xylitol still remains obscure, but an increased absorption o f calcium may be involved. In conclusion, dietary xylitol supplementat ion in rats seems to retard the bone resorption in a dose-dependent wa y. The effect is achieved rapidly and is maintained at least over a pe riod of 1 month xylitol feeding.