This game is becoming very educational. After a bit of searching I found:
Xylitol = wood sugar or birch sugar
(a sugar alcohol sweetener used as a naturally occurring sugar substitute. It is found in the fibers of many fruits and vegetables, including various berries, corn husks, oats, and mushrooms. It can be extracted from corn fiber, birch, raspberries, plums, and corn. Xylitol is roughly as sweet as sucrose with only two-thirds the food energy. http://en.wikipedia.org/w/index.php?...ar&redirect=no )