[Effect of a lactose-free diet on irritable bowel syndrome].

Pathological lactose-H2-breath test is a frequent finding in patients with suspected irritable bowel syndrome. We found it in 33 of 55 patients (60%) with chronic non-specific abdominal symptoms. Follow-up examinations after 15 months (mean) exhibited that lactose-free diet relieved symptoms in 57% of these patients completely or nearly completely. In contrast, only 12% of the patients without lactose malabsorption showed equal amelioration on the various unspecific diets and medications. The lactose-free diet succeeded particularly in young patients and patients with a short history of complaints. Therefore, we recommend lactose-H2-breath test in all patients with suspected irritable bowel syndrome for optimizing therapy.