[Breath hydrogen levels do not predict fiber intolerance in irritable bowel syndrome with constipation]

Irritable Bowel Syndrome (IBS) is characterized by the worsening of symptoms with a high fiber diet. This intolerance could be related to an increase in colonic bacterial fermentation. The hydrogen breath test (HBT) is a marker of the intestinal micro flora fermentative capacity.

To assess if there is an association between hydrogen (H2) levels and clinical changes between diets with and without bran.

10 women with predominantly constipated irritable bowel syndrome (Rome II criteria) received a lowfiber diet during one week. This phase was followed by a second 7 day period with the same diet but supplemented with 12 g of crude dietary fiber. At the end of both periods, patients completed a symptom scale (Lickert type) and performed a HBT.

Comparing both periods with a different diet the median difference in the clinical scale score (-2.5) shows a tendency favorable to the diet without bran, p = 0.048. In the fiber period the median increase of 2 ppm in H2 values was not significant deferent. Neither was possible to establish an association between breath H2 and the clinical response to a fiber diet.

In this pilot study we could not detect ary association between breath H2 levels and the clinical response to dietary fiber.