Factors affecting fasting breath hydrogen levels in healthy adults: a study in two continents.

Factors affecting fasting breath hydrogen (FBH) levels, which are known to vary in healthy individuals, have not been clearly identified. To study the effect of dietary habits on FBH levels, we tested 102 healthy adults in the United States (n = 33, group A) and India (n = 69, group C). Twenty-two Indian immigrants in the United States (group B) were also tested to study the effects of migration on FBH levels. Volunteers in groups A and B had similar FBH levels in comparison to those noted in group C, which were significantly higher. Orocecal transit time determined in these three groups supported our hypothesis that shorter transit times are associated with higher FBH levels. We recommend that the "normals" for FBH levels in population groups with different dietary habits be established for their diagnostic usefulness.