Hydrogen breath test--diet and basal H2 excretion: a technical note

Area of Science:

• Gastroenterology
• Clinical Diagnostics
• Nutritional Science

Background:

• Hydrogen breath tests (HBTs) are crucial for diagnosing gastrointestinal disorders.
• Accurate HBT interpretation requires low basal hydrogen (H2) excretion, typically achieved through 12-hour fasting.
• The impact of pre-test dietary modifications, specifically reducing complex carbohydrates, on basal H2 excretion remains under-investigated.

Purpose of the Study:

• To evaluate the effect of a pre-test low-carbohydrate diet on basal H2 excretion in HBTs.
• To determine if this dietary intervention reduces the number of patients excluded from HBTs due to elevated basal H2 levels.

Main Methods:

• Retrospective analysis of two patient cohorts (n=500 each) undergoing lactose tolerance tests.
• Cohort 1 (1997-1998): Standard 12-hour fasting protocol.
• Cohort 2 (2007-2008): 12-hour fasting plus a 24-hour low-complex carbohydrate diet.

Main Results:

• Mean basal H2 excretion was significantly lower in the low-carbohydrate diet group (2.46 ± 6.8 ppm) compared to the standard fasting group (4.73 ± 3.3 ppm; p < 0.0001).
• Patient exclusion rates due to high basal H2 were substantially reduced: 1.4% (7/500) in the low-carbohydrate group versus 9.2% (46/500) in the standard fasting group.
• The low-carbohydrate diet intervention demonstrated a significant improvement in test eligibility.

Conclusions:

• This study provides the first objective evidence supporting the benefit of a pre-test low-carbohydrate diet in HBTs.
• Reducing complex carbohydrate intake prior to HBTs effectively lowers basal H2 excretion and minimizes test exclusions.
• This dietary strategy enhances the reliability and clinical utility of hydrogen breath tests.