Abstract
To investigate the fate and utilization of D-tagatose (TAG), the maximum permissive dosage (MPD) of TAG for osmotic diarrhea was determined, together with blood glucose and insulin levels, the urinary excretion and blood concentration of TAG, and breath hydrogen excretion after TAG ingestion. The MPD of TAG was 0.25 g/kg b.w., and similar to that of sorbitol. When 5 g or 10 g of TAG was ingested, approximately 2% of the TAG was excreted into urine during 6 h, but no TAG was detected in blood. Blood glucose and insulin levels were unaffected by TAG ingestion. Breath hydrogen excretion was detectable after ingestion of 10 g, but not 5 g of TAG. The level of excretion was clearly less than that after ingestion of 5 g of fructooligosaccharide (FOS), and the initiation of excretion was comparatively delayed. Furthermore, TAG was scarcely decomposed in cultures of human feces. These results demonstrate that after ingestion of 10 g of TAG, about 5 g of it is absorbed from the small intestine, and approximately 2% of the ingested TAG is excreted into urine. It is suggested that any TAG not absorbed from the small intestine is slowly metabolized to volatile fatty acids by intestinal microbes to produce energy. The estimated available energy of TAG was 2 kcal/g.
