Oral xylose isomerase decreases breath hydrogen excretion and improves gastrointestinal symptoms in fructose malabsorption - a double-blind, placebo-controlled study

Summary Background Incomplete resorption of fructose results in increased colonic hydrogen production and is a frequent cause of abdominal symptoms. The only treatment available is diet. Aim To study whether orally administered xylose isomerase (XI), an enzyme that catalyses the reversible isomerisation of glucose and fructose, can decrease breath hydrogen excretion in patients with fructose malabsorption. Methods Patients received 25 g fructose in 100 mL water together with either placebo or XI capsules. Primary endpoint was the reduction in breath hydrogen excretion, as assessed by the area under the breath hydrogen curve over 4 h (AUC). A secondary endpoint was the reduction in abdominal pain, bloating and nausea assessed on a visual analogue scale (VAS, range: 0–10). A P value