Hydrogen Breath Test - Diet and Basal H-2 Excretion: A Technical Note

Background: Hydrogen breath tests are widely used in clinical practice. For a correct evaluation of data, low basal H 2 excretion is required, thus, 12-hour fasting is usually prescribed. An additional reduction in the intake of complex carbohydrates in the preceding 24 h is suggested in some centers. The issue, however, has never been directly investigated. Aim: The aim of the present study was to analyze the effect of the pretest diet on the basal H 2 excretion and the number of subjects excluded from the test due to high basal H 2 excretion. Methods: Two cohorts of 500 consecutive patients undergoing a lactose tolerance test in the years 19971998 (when 12-hour fasting was required) and in 2007-2008 (when a low-carbohydrate diet in the preceding 24 h was also prescribed) were retrospectively reviewed. Results: The mean basal H 2 excretion was significantly lower (p < 0.0001) in the low-carbohydrate diet group (2.46 +/- 6.8 vs. 4.73 +/- 3.3 ppm). In 1997-1998, 46/500 patients (9.2%) were excluded from the test due to basal H 2 values as compared to 7/500 (1.4%) in the period 2007-2008. Discussion: To the best of our knowledge, ours is the first study to provide objective data on the advantage offered by reducing the intake of complex carbohydrates before H 2 breath tests. Copyright (C) 2010 S. Karger AG, Basel