Category: sweetener
Aliases: E420, D-Glucitol, D-Sorbitol, Glucitol, (2S,3R,4R,5R)-Hexane-1,2,3,4,5,6-hexol, INS 420
Six-carbon sugar alcohol (hexitol), the reduced form of glucose/fructose. Slowly and incompletely absorbed in the small intestine by passive diffusion; the absorbed fraction is oxidised by hepatic sorbitol dehydrogenase to fructose, which then enters glycolysis — the second limb of the polyol (aldose-reductase/SDH) pathway that also operates intracellularly under hyperglycaemia. Because absorption is slow and partial, it carries roughly half the caloric value of sucrose and a low glycaemic response largely independent of insulin for its first metabolic steps. The unabsorbed remainder is osmotically active in the colon, drawing water and undergoing bacterial fermentation, which underlies its use as an osmotic laxative and its dose-dependent flatulence/diarrhoea (a FODMAP polyol). About 60% as sweet as sucrose.
E420 (INS 420); about 60% as sweet as sucrose, ~2.6 kcal/g. JECFA/EU ADI "not specified" and GRAS/permitted as a sweetener, humectant and bulk laxative. Laxative/osmotic GI effects are dose-dependent (loose stools and gas typically above ~20-50 g/day); EU requires an "excessive consumption may produce laxative effects" label.