['To test the effect of the concomitant ingestion of glucose or lipids on sorbitol absorption in the human small intestine using the hydrogen breath test.', 'After an overnight fast, on four occasions separated by at least 1 week 14 healthy volunteers randomly ingested 20 g sorbitol alone, 20 g sorbitol and 20 g glucose, 20 g sorbitol and 9 g lipids, and 10 g lactulose. Hydrogen concentration was measured in end-expiratory samples every 10 min for 3 h, and then every 30 min for 5 h. Sorbitol malabsorption was calculated from the ratio of the areas under the curve.', 'The estimated rate of sorbitol malabsorption was 98 +/- 14% (mean +/- SEM) when sorbitol was ingested alone, and was significantly lower when ingested with glucose or lipids (68 +/- 10 and 70 +/- 7%, respectively; P < 0.05). Orocaecal transit times did not differ significantly between the different time periods.'] Is sorbitol absorption in the healthy human small intestine increased by the concomitant ingestion of glucose or lipids?