Pentitols

Pentitols are sugar alcohols with five carbon atoms, a subset of the larger class of alditols. They are typically formed by the chemical or enzymatic reduction of aldopentose or ketopentose sugars and have the empirical formula C5H12O5. Like other alditols, pentitols are polyols with multiple hydroxyl groups, are not reducing sugars, and exist as several stereoisomers (D- and L- forms and other diastereomers).

Common pentitols include ribitol (from ribose), arabitol or arabitol (from arabinose), xylitol (from xylose), lyxitol (from lyxose), and iditol (from idose). Each of these occurs in multiple stereochemical forms, contributing to a range of isomers used in various applications.

Industrial and dietary relevance centers on their use as low-calorie sweeteners and excipients. Xylitol is the best known pentitol and is widely used in sugar-free products such as chewing gums and toothpaste, partly for its dental benefits and stability. Other pentitols are less common in consumer foods but are valued as humectants, stabilizers, or pharmaceutical excipients due to their sweetness, swelling properties, and non-volatile nature. Sweetness levels vary among the isomers and are generally less than that of sucrose.

Safety and metabolism: consumption of sugar alcohols can cause gastrointestinal discomfort, particularly at high doses, because they are incompletely absorbed in the small intestine and are fermented by gut bacteria in the colon. They provide fewer calories than sugars and do not raise blood glucose as quickly, though individual tolerance and effects depend on the specific pentitol and the amount consumed.