[Reproducibility of orocecal transit time and hydrogen production measured by breath tests]

The hydrogen breath test after a lactulose oral load in the fasting period is currently used to measure mouth to cecum transit time (MCTT). However, the reproducibility of this test is poor, and normal values are very scattered. The aim of the study was to determine the reproducibility of hydrogen breath test for MCTT measurement and hydrogen production after administration of 2 disaccharides: lactulose and lactitol ingested in the fasting state and postprandial period. Twelve healthy volunteers (6 men and 6 women; mean age = 34.6 +/- 9.6 years) were studied eight times in a random order, each disaccharide being studied twice in the fasting state and twice in the postprandial period. In the later, lactulose or lactitol was ingested 30 min after a liquid meal completely absorbed (400 kcal; glucide: 55 p. 100, lipid: 30 p. 100, protein: 15 p. 100; 400 ml of Inkopeptide). The MCTT was significantly increased with both disaccharides in the postprandial period as compared with the fasting state (P less than 0.0001). There was nos significant correlation between the 2 measurements of the MCTT in the fasting state, in contrast, the 2 measurements of the MCTT were closely related in the fed state (r = 0.62, P less than 0.05, et r = 0.79, P less than 0.003 for lactulose and lactitol respectively). During both periods no significant difference was found in the MCTT between lactulose and lactitol. As well, hydrogen production did not differ between the 2 disaccharides, but was significantly increased in the postprandial period, and in non methane producers.(ABSTRACT TRUNCATED AT 250 WORDS)