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Gastroenterology Research and Practice
Volume 2012 (2012), Article ID 214102, 6 pages
Research Article

Probiotics, Symptoms, and Gut Microbiota: What Are the Relations? A Randomized Controlled Trial in Subjects with Irritable Bowel Syndrome

1Department of Research, Innlandet Hospital Trust, 2819 Gjøvik, Norway
2Unit for Applied Clinical Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway
3Department of Medicine, Østfold Hospital Trust, 1603 Fredrikstad, Norway
4Department of Medicine, Innlandet Hospital Trust, 2819 Gjøvik, Norway
5Nofima Mat AS, 1431 Ås, Norway

Received 23 March 2012; Revised 17 June 2012; Accepted 18 June 2012

Academic Editor: P. Gionchetti

Copyright © 2012 Per G. Farup et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Introduction. Knowledge of the mechanism of action of probiotics in subjects with irritable bowel syndrome (IBS) is imperfect. Objective. This trial aimed at discriminating between a direct effect on the gut wall and an indirect effect caused by modulation of the fecal microbiota. Design. Randomized, double-blind, crossover trial. Material and Methods. Patients with IBS were given one capsule of 1010 CFU L. plantarum MF 1298 or placebo once daily. Symptoms were registered (score 0–15) and feces collected at the end of each period. The gut microbiota was analyzed with 16S rRNA gene analyses and results reported as proportions of Bacteroides, Faecalibacterium, and Lachnospiraceae and Simpson’s D diversity score. Results. Sixteen participants (11 women) with a mean age of 50 years (SD 11) were available for the analyses. Intake of L. plantarum MF 1298 was associated with a significant aggravation of symptoms, but neither intake of L. plantarum MF 1298 nor symptoms were associated with the composition of the fecal microbiota (P values >0.10). Conclusions. The trial indicates that the symptomatic aggravation related to intake of L. plantarum MF 1298 was a direct effect of the microbe on the gut wall and not caused by changes in the fecal microbiota.