Hydrogen excretion after ingestion of five different sugar alcohols and lactulose.

The breath hydrogen excretion was measured for 5 h after the initial rise on seven subjects who consumed randomly, and after 5 d of adaptation, equimolar amounts of sorbitol (10 g), mannitol (10 g), maltitol (19 g), Palatinit (19 g anhydrous), lactitol (19 g anhydrous), lactulose (19 g) in aqueous solution. The mean mouth-to-caecum transit time was 1.5 h, which was not significantly different from one carbohydrate to another, but varied significantly from one subject to another (0.7-2.4 h). Suprabasal increment of breath hydrogen after lactitol was significantly higher than that from the other polyols (P less than 0.001) over 5 h. Lactitol and lactulose, which are known to be totally undigested in the small intestine, gave the highest mean incremental area under the breath hydrogen curve, 327 p.p.m. H2 over 5 h and 224 p.p.m. H2 over 5 h, respectively. The values for the other test compounds ranged from 145 to 209 p.p.m. H2 over 5 h, which suggest that there had been only partial absorption in the small intestine.