glucide

Glucide is a historical and still-used term for a carbohydrate, a broad class of organic compounds composed of carbon, hydrogen, and oxygen with the general empirical formula (CH2O)n. In contemporary English and international usage, carbohydrates or saccharides are preferred, but glucide remains common in older literature and in some languages, notably French. Glucides encompass monosaccharides, disaccharides, oligosaccharides, and polysaccharides.

Monosaccharides include glucose, fructose, and galactose; disaccharides include sucrose, lactose, and maltose; polysaccharides include starch, glycogen, and cellulose. Glucides are classified further by functional group: aldoses and ketoses, and by the number of sugar units (triose, tetrose, pentose, hexose). Many glucides have a ring structure in solution.

In plants, starch stores energy; cellulose provides structural support. In animals, glycogen stores energy in liver and muscle tissue. Monosaccharides such as glucose serve as primary metabolic fuels, entering pathways like glycolysis to generate ATP. Some glucides also serve structural roles (cellulose in plants) and informational roles when present as components of glycoproteins and glycolipids.

Dietary carbohydrates are a major energy source; digestion uses enzymes such as amylase, sucrase, and lactase to hydrolyze glycosidic bonds; absorbed monosaccharides enter the bloodstream and are used or stored as glycogen or fat.

The term derives from the Greek glykys, meaning sweet, reflecting the common taste of many sugar units.