From the Guidelines
Bifidobacterium and Lactobacillus are two genera with species that have evidence supporting their use in Irritable Bowel Syndrome (IBS), specifically Bifidobacterium longum and Lactobacillus acidophilus. These probiotics can help in two ways:
- Reduce abdominal pain by restoring gut microbiota balance and modulating the gut-brain axis, which influences pain perception and intestinal motility 1
- Improve global IBS symptoms, such as bloating and intestinal inflammation, by strengthening the gut barrier and regulating immune responses 1 However, probiotics will not cure IBS completely, as the condition is multifactorial with genetic, psychological, and environmental components that probiotics alone cannot address 1. When using these probiotics for IBS, a typical regimen involves taking supplements containing at least 1 billion colony-forming units (CFUs) daily for 4-8 weeks to evaluate effectiveness, as seen in studies with L plantarum 299v and the 8-strain combination of L paracasei subspparacasei, L plantarum, L acidophilus, L delbrueckii subspbulgaricus, B longum subsplongum, B breve, B longum subspinfantis, and S salivarius subsp thermophilus 1. Results vary between individuals, and it may take several weeks of consistent use before noticing improvements in symptoms, with the mechanism behind their effectiveness involving competitive inhibition of pathogenic bacteria, production of short-chain fatty acids that nourish intestinal cells, and modulation of gut motility and sensitivity 1.
From the Research
Probiotic Strains for IBS
- Two strains that have evidence in IBS are:
- Genus: Lactobacillus, Species: Lactobacillus acidophilus
- Genus: Bifidobacterium, Species: Bifidobacterium bifidum
Benefits of Probiotics in IBS
- Probiotics may help in IBS by:
Limitations of Probiotics in IBS
- One thing probiotics may not help with in IBS is:
- Completely eliminating symptoms, as the certainty in the evidence for efficacy by GRADE criteria was low to very low across almost all analyses 2