Sucrose intolerance in adults with common functional gastrointestinal symptoms.

Sucrose intolerance is a form of carbohydrate malabsorption caused by sucrase-isomaltase deficiency that is more common than recognized. Its symptoms include postprandial cramping, bloating, gas, and diarrhea, which are difficult to distinguish from irritable bowel syndrome. The gold standard test for diagnosing sucrase deficiency is a sucrase enzyme assay of duodenal biopsies obtained by endoscopy. Hydrogen-methane or 13 C-sucrose breath tests are noninvasive methods to screen for sucrose malabsorption. This chart review included 258 consecutive adults (47 men and 211 women) with chronic unexplained gastrointestinal symptoms and suspected sucrose intolerance who were screened with a hydrogen-methane or 13 C-sucrose breath test. The incidence of sucrose malabsorption with two different hydrogen-methane breath tests was 34.4% (21/61) (Commonwealth Diagnostics International, Inc., Salem, MA) and 40% (20/50) (Aerodiagnostics, Concord, MA). The incidence of sucrose malabsorption with the 13 C-sucrose breath test was 26.5% (39/147). In a subgroup of patients with positive breath tests and clinical follow-up, counseling regarding diet and/or enzyme replacement led to symptomatic improvement in 26/43 (60%). In conclusion, sucrose malabsorption may present with irritable bowel syndrome symptoms in a proportion of adult patients, and breath tests may be useful in identifying sucrose malabsorption and differentiating it from other gastrointestinal disorders.