title: Probiotics and irritable bowel syndrome.
abstract: BACKGROUND
  Irritable bowel syndrome (IBS) is a major cause of abdominal discomfort and gut dysfunction worldwide. It is a poorly understood functional gastrointestinal disorder for which no effective medication is available. It is a benign condition, but its social and economic burden is significant. The symptoms consist of abdominal pain, bloating, flatulence, and irregular bowel movements. Alterations in the intestinal microbiota and mucosal inflammation may contribute to the development of IBS and probiotics could thus relieve the symptoms. This review gives an overview on the existing data on the effects of probiotics on the gastrointestinal symptoms of IBS.
  
  
  METHODS
  A PUBMED search was made to review the relevant literature, and additional studies were obtained from the references of the selected articles.
  
  
  RESULTS
  Clinical trials suggest that certain probiotics or combinations of bacteria have beneficial effects on the IBS symptoms. However the heterogeneity of studies, e.g. suboptimal study design, inadequate number of subjects, different doses and vehicles, inadequate length, make it difficult to compare the differences between probiotics and the effect may be strain-specific.
  
  
  CONCLUSIONS
  Though evidence is very promising, no general recommendations on the use of probiotics in IBS can be given yet. Further clinical trials and data on the mechanisms of action are needed. Probiotics are considered safe and if future scientific data is able to substantiate their efficacy in IBS, they certainly could be a treatment option in relieving the symptoms in IBS.
authors.affiliation: Medical Nutrition Physiology, Pharmacology, Institute of Biomedicine, University of Helsinki, Helsinki, Finland.
authors.forename: Riitta
authors.initials: R
authors.lastname: Korpela
authors.forename: Leena
authors.initials: L
authors.lastname: Niittynen
keywords: IBS; bifidobacteria; gastrointestinal symptoms; irritable bowel syndrome; lactobacilli; probiotic