Increased bone volume and bone mineral content in xylitol-fed aged rats

Background. Our previous studies have shown that dietary xylitol supplement ation protects against the loss of bone mineral after ovariectomy. The ovar iectomy-induced decrease in trabecular bone volume is significantly retarde d by dietary xylitol. Objective: To study whether dietary xylitol can prote ct against bone loss also during aging, a long-term experimental study was performed with rats. Methods: Twenty-four male Sprague-Dawley rats were div ided into two groups. The rats in the control group were fed a basal RM1 di et, while the rats in the experimental group were continuously fed the same diet supplemented with 10% (w/w) xylitol. The rats were killed after 20 mo nths. Their tibiae were used for the analyses of bone density and trabecula r bone volume, and their femurs were used for the scanning analyses with pe ripheral quantitative computed tomography (pQCT). Results: The tibial densi ty of the xylitol-fed aged group (1.73 +/- 0.14 g/mm(3)) was significantly greater than that of the aged group without xylitol (1.56 +/- 0.14 g/ mm(3) ). The trabecular bone volume of the xylitol-fed rats was 21.2 +/- 4.0%. It was significantly greater than that of the rats not receiving xylitol (9.3 +/- 4.3%). The pQCT-measured cortical bone mineral density and the pQTC-me asured cortical bone mineral content of the femoral diaphysis were signific antly greater in the xylitol-fed group than in the control group. The trabe cular bone mineral density and the trabecular bone mineral content of the f emoral distal metaphysis were also significantly greater in the xylitol-fed group than in the non-xylitol group. The total bone mineral density and th e total bone mineral content of the femoral neck in the xylitol-fed aged gr oup significantly exceeded those in the aged group without xylitol suppleme ntation. Conclusions: A continuous moderate dietary xylitol supplementation leads to increased bone volume and increased bone mineral content in the l ong bones of aged rats. This indicates a xylitol-induced protection against aging-related osteoporotic changes. Copyright (C) 2001 S. Karger AG, Basel .