(3S,4S,5R)-1,3,4,5,6-pentahydroxyhexan-2-one

Oral tagatose significantly blunts the rise in plasma glucose seen after oral glucose in patients with diabetes mellitus in a dose-dependent manner without significantly affecting insulin levels. The minimal elevation of plasma tagatose levels in normal patients and the adverse gastrointestinal effects seen following larger doses of tagatose support poor absorption of this hexose and suggest that tagatose may act by attenuating glucose absorption in the intestine.

he steps in the metabolism of tagatose are identical to those for fructose or fruit sugar but tagatose is incompletely absorbed. Only 15-20 percent of tagatose is absorbed in the small intestine. The major part of ingested tagatose is fermented in the colon by indigenous microflora, resulting in the production of short-chain fatty acids. The short chain fatty acids are absorbed almost completely and metabolized.