Sugar malabsorption in functional abdominal bloating: a pilot study on the long-term effect of dietary treatment.

Background: Functional abdominal bloating is a functional bowel disorder dominated by a feeling of abdominal fullness without sufficient criteria for another functional gastrointestinal disorder. Gas-related complaints (i.e., passage of flatus), which are present in a subgroup of these patients, might be associated with carbohydrate malabsorption.

Aim: To evaluate the presence of lactose and/or fructose plus sorbitol malabsorption, and the long-term efficacy of malabsorbed sugar-free diets, in patients with Rome II criteria of functional abdominal bloating and gas-related symptoms.

Methods: Thirty-six consecutive patients (age, 51+/-3.1 years; sex, 12 M, 24 W) with Rome II criteria of functional abdominal bloating and gas-related symptoms were included in a pilot study. In all cases, the presence of malabsorption of both lactose (20 g) and fructose plus sorbitol (20+3.5 g) was assessed by means of hydrogen breath test. Patients with sugar malabsorption were put on a malabsorbed sugar-free diet. Follow-up visits were scheduled at both 1 and 12 months after starting the diet. Global rating scales of change as compared to the beginning of the study were used to assess symptom changes.

Results: Twenty-six of 36 patients (72.2%) presented sugar malabsorption (six lactose, 12 fructose plus sorbitol, and eight both). Seventeen of the 26 (65%) patients with malabsorption had symptoms of sugar intolerance during the 3-h breath testing period. All 26 were put on malabsorbed sugar-free diets. Eighty-one per cent of patients referred clinical improvement at 1-month visit, which was maintained at 12 months in 67% of them (complete improvement in 50% and partial improvement in 16.7%).

Conclusions: Sugar malabsorption and intolerance seem to be frequent in patients with functional abdominal bloating and gas-related complaints. A malabsorbed sugar-free diet might be a long-term effective therapy in a high percentage of patients. Further controlled clinical trials are warranted.