Pooled data from multiple trials provide some support for the use of several individual probiotics or combinations of them to improve IBS symptoms.
Researchers conducted a systematic review and meta-analysis of 82 randomized controlled trials, involving 10,332 adult patients with IBS, that compared probiotics with placebo.
They calculated relative risk of global symptoms, abdominal pain, or abdominal bloating/distention persisting after therapy.
For global symptoms, there was moderate certainty evidence for benefit of Escherichia strains, low certainty evidence for benefit of some Lactobacillus, and very low certainty for combination probiotics, LacClean Gold S, Duolac 7s, and Bacillus strains.
For abdominal pain, there was low certainty evidence for benefit of Saccharomyces cerevisae I-3856 and Bifidobacterium strains and very low certainty for combination probiotics, Lactobacillus, Saccharomyces, and Bacillus strains.
For abdominal bloating/distention, there was very low certainty for benefit of combination probiotics and Bacillus strains.
Probiotics for the subgroup of patients with IBS and constipation is not supported by the evidence due to limited data.
"Some combinations of probiotics or strains may be beneficial in IBS," the authors write. However, "if gastroenterologists are to be able to recommend probiotics in patients with confidence, a better evidence base is needed," they add.
Vivek C. Goodoory, MBChB, and Mais Khasawneh, MBBS, with Leeds Gastroenterology Institute, Leeds, UK, are joint first authors on the study, which was published online August 2 in Gastroenterology. The study had no specific funding.
Few trials had a low risk of bias across all domains, and there was significant heterogeneity between studies, as well as evidence of publication bias in some analyses. Trial duration was short, compared with the likely chronicity of IBS symptoms.
Goodoory and Khasawneh have no relevant disclosures. Some authors report honoraria and consulting fees from probiotic companies.