[Xylitol, mechanisms of action and uses].

Xylitol is recommended as a sugar substitute and is claimed not only to be non-cariogenic, but also to exhibit an anti-caries effect. An interesting aspect of xylitol is that it has a certain bacteriostatic effect. Xylitol is taken up by many strains of Strep mutans and Strep sanguis even if these organisms are unable to metabolize xylitol. It enters the bacteria by the phospho-transferase system. Xylitol-phosphate inhibits the glycolysis probably at the phosphofructokinase level, and is also de-phosphorylated and expelled through a "futile cycle". The combination xylitol and sorbitol is particularly interesting, since xylitol inhibits the metabolization of sorbitol by Strep mutans and sorbitol also appears to potentiate the bacteriostatic effect of xylitol. Furthermore the combination is favourable from an economical point of view since sorbitol is less expensive than xylitol. Xylitol induces diarrhea if consumed in considerable amounts and is thus only suitable in products like chewing gum and tablets.