Category: sweetener
Aliases: D-Tagatose, Rare sugar, D-(-)-Tagatose
A ketohexose monosaccharide, the C-4 epimer of fructose (and keto isomer of galactose), produced commercially by isomerising galactose obtained from lactose/whey. It is ~90% as sweet as sucrose but low-calorie (~1.5 kcal/g): only a minor fraction is absorbed in the small intestine (partly via GLUT5, like fructose) and metabolised hepatically by ketohexokinase to tagatose-1-phosphate and onward through fructose-like pathways, while the majority passes to the colon and is fermented by microbiota to short-chain fatty acids (a prebiotic effect) with gas and an osmotic/laxative potential at high intake. Hepatic handling is largely insulin-independent, giving a low glycaemic response, and it has been studied for blunting post-prandial glucose excursions. Non-cariogenic.
A "rare sugar" bulk sweetener ~90% as sweet as sucrose at ~1.5 kcal/g; FDA GRAS and an EU authorised novel food (no E-number; not a high-intensity additive). Low glycaemic and prebiotic, but large doses are osmotically laxative/flatulent.