Unclear abdominal discomfort: pivotal role of carbohydrate malabsorption.
OBJECTIVE
Carbohydrate malabsorption is frequent in patients with functional gastrointestinal disorders and in healthy volunteers and can cause gastrointestinal symptoms mimicking irritable bowel syndrome (IBS). The aim of this study was to investigate the prevalence of symptomatic lactose and fructose malabsorption in a large population of patients with IBS-like symptoms based on Rome II criteria.


METHODS
Patients with unclear abdominal discomfort (n = 2,390) underwent lactose (50 g) and fructose (50 g) hydrogen (H2) breath tests and depending on the results further testing with 25 g fructose or 50 g glucose, or upper endoscopy with duodenal biopsies. Additionally, this population was investigated regarding the prevalence of small intestinal bacterial overgrowth (SIBO) based on glucose breath test and celiac disease.


RESULTS
Of the 2,390 patients with IBS-like symptoms, 848 (35%) were symptomatic lactose malabsorbers and 1,531 (64%) sympto-matic fructose malabsorbers. A combined symptomatic carbohydrate malabsorption was found in 587 (25%) patients. Severe fructose malabsorbers (pathologic 25 g fructose test) exhaled significantly higher H2 concentrations in the 50 g test than pa-tients with negative 25 g fructose test (P < 0.001). Out of 460/659 patients with early significant H2 increase in the lactose and fructose test who underwent a glucose breath test, 88 patients had positive results indicative of SIBO and they were sig-nificantly older than patients with negative test result (P < 0.01). Celiac disease was found in 1/161 patients by upper endoscopy.


CONCLUSIONS
Carbohydrate malabsorption is a frequent but underestimated condition in patients with IBS-like symptoms although diagnosis can be easily confirmed by H2 breath testing.
Department of Internal Medicine, Institute of Neurogastroenterology and Motility, Martin-Luther Hospital, Academic Teaching Institution of Charité - University Medical Center, Berlin, Germany.
Miriam
M
Goebel-Stengel
Charité Center for Internal Medicine and Dermatology, Division of General Internal and Psychosomatic Medicine; Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.
Andreas
A
Stengel
Department of Internal Medicine, Institute of Neurogastroenterology and Motility, Martin-Luther Hospital, Academic Teaching Institution of Charité - University Medical Center, Berlin, Germany.
Marco
M
Schmidtmann
Department of Internal Medicine, Institute of Neurogastroenterology and Motility, Martin-Luther Hospital, Academic Teaching Institution of Charité - University Medical Center, Berlin, Germany.
Ivo van der
Iv
Voort
Charité Center for Internal Medicine and Dermatology, Division of General Internal and Psychosomatic Medicine; Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.
Peter
P
Kobelt
Department of Internal Medicine, Institute of Neurogastroenterology and Motility, Martin-Luther Hospital, Academic Teaching Institution of Charité - University Medical Center, Berlin, Germany.
Hubert
H
Mönnikes
Breath tests; Fructose; Hydrogen; Irritable bowel syndrome; Lactose