Q: Some hard candy says, “sugar free.” But it also says, “15 mg sugar alcohol.” What’s going on?
Answer : The candy contains no sugar of the sort you’d find in a sugar bowl, but does contain a sweetener such as xylitol. Lynne M. Ausman, DSc, RD, director of the Biochemical and Molecular Nutrition Program at Tufts’ HNRCA Cardiovascular Nutrition Laboratory, explains: “The name ‘sugar’ generally refers to ‘table sugar,’ which is sucrose (a disaccharide, meaning it’s formed from two simpler sugars called monosaccharides). This is what is assumed for labeling purposes. ‘Sugar’ is also a general name for several types of carbohydrates, many of which have sweetening power. The sugar alcohols are generally monosaccharides like glucose (one sugar unit), but they have a different configuration around the carbon atoms such that every carbon atom has an alcohol unit on it. Xylitol, a sugar alcohol commonly used in gums and after-dinner mints, helps prevent tooth decay because bacteria find it difficult to break down. The acid from the breaking down is what dissolves the tooth and makes a cavity.” Because sugar alcohols are less well absorbed, Xylitol also has the advantage of delivering about 40% fewer calories and 75% fewer carbohydrates than table sugar.