Xylitol

Xylitol is a sugar alcohol used as a sugar substitute. The name derives from Ancient Greek: ξύλον, xyl, 'wood' + suffix -itol, used to denote sugar alcohols. Xylitol is categorized as a polyalcohol or sugar alcohol (specifically an alditol). It has the formula CH2OH(CHOH)3CH2OH. It is a colorless or white solid that is soluble in water. Use of manufactured products containing xylitol may promote better dental health, but evidence is lacking on whether it prevents cavities. Xylitol is a sugar alcohol used as a sugar substitute. The name derives from Ancient Greek: ξύλον, xyl, 'wood' + suffix -itol, used to denote sugar alcohols. Xylitol is categorized as a polyalcohol or sugar alcohol (specifically an alditol). It has the formula CH2OH(CHOH)3CH2OH. It is a colorless or white solid that is soluble in water. Use of manufactured products containing xylitol may promote better dental health, but evidence is lacking on whether it prevents cavities. Xylitol has an E number E967 when used as a food additive within EU. Xylitol is naturally occurring in small amounts in plums, strawberries, cauliflower, and pumpkin; humans and animals make trace amounts during metabolism of carbohydrates. Unlike most sugar alcohols, xylitol is achiral. Most other isomers of pentane-1,2,3,4,5-pentol are chiral, but xylitol has a plane of symmetry. Industrial production starts with lignocellulosic biomass from which xylan is extracted; raw biomass materials include hardwoods, softwoods, and agricultural waste from processing maize, wheat, or rice. The xylan polymers can be hydrolyzed into xylose, which is catalytically hydrogenated into xylitol. The conversion changes the sugar (xylose, an aldehyde) into the primary alcohol, xylitol. Impurities are then removed. The processing is often done using standard industrial methods; industrial fermentation involving bacteria, fungi, or yeast, especially Candida tropicalis, are common, but are not as efficient. Xylitol is used as a sugar substitute in manufactured products, such as drugs or dietary supplements, confections, toothpaste, and chewing gum, but is not a common household sweetener. Xylitol has negligible effects on blood sugar because it is metabolized independently of insulin. Absorbed more slowly than sugar, xylitol supplies 40% fewer calories than table sugar. It is approved as a food additive in the United States. Xylitol has about the same sweetness as sucrose, but more sweetness than similar compounds like sorbitol and mannitol. It has a glycemic index of 7 (100 for glucose). Because xylitol and other polyols are heat stable, they do not caramelise as sugars do, and they also lower the freezing point of mixtures in which they are used. No health risk exists for normal levels of consumption, and the European Food Safety Authority has not set a limit on daily intake of xylitol. Due to the adverse laxative effect that all polyols have on the digestive system in high doses, xylitol is banned from soft drinks in the EU. Similarly due to a 1985 report, by the EU Scientific Committee on Food, stating that 'ingesting 50 g a day of xylitol can cause diarrhea', tabletop sweeteners containing xylitol are required to display the warning: 'excessive consumption may induce laxative effects'. Chewing gum containing xylitol is permitted. As of 2015, clinical trials examining whether xylitol alone or with other agents can prevent cavities found the evidence was too poor to allow generalizations, although when children with permanent teeth use fluoride toothpaste with xylitol, they may get fewer cavities than when using fluoride toothpaste without it. People apparently get fewer cavities when they chew gum sweetened with xylitol (or similar polyols such as sorbitol) than when they chew gum sweetened with sucrose. In 2008, the European Food Safety Authority (EFSA) evaluated the literature on xylitol, concluding, 'xylitol chewing gum reduces the risk of cavities in children'. The claim required rewording because xylitol chewing gum is not a medicine, thus can 'not be claimed to reduce the risk of a disease'. In 2011, EFSA approved a claim that replacing sugar with xylitol and similar sweeteners 'may maintain tooth mineralisation compared with sugar-containing foods.'