How Do Probiotics Affect Gut Health?

What the research shows

High-quality systematic reviews and randomized controlled trials indicate that probiotics can influence gut health by modulating intestinal permeability and gut barrier integrity. Akkermansia shows promise in reducing intestinal permeability associated with obesity, though clinical trial results are inconsistent. Streptococcus thermophilus ST10 combined with tara gum significantly improved intestinal barrier function in healthy subjects. Lactobacillus delbrueckii subsp. bulgaricus-containing probiotics improved mucosal barrier function in diarrhea-predominant IBS patients. Bifidobacterium is commonly found in formulations that improve gut microbiota and reduce permeability, especially in older adults. However, some studies, such as probiotic use to prevent aspirin-induced permeability increases or in chronic kidney disease, show uncertain or no clear benefits. Evidence quality varies, and strain-specific effects are important. More standardized, larger trials are needed.

Best studied probiotic strains

Who may benefit

Safety

Probiotic supplementation was generally safe with minimal and non-serious adverse events reported, such as mild gastrointestinal symptoms (flatulence, nausea, diarrhea, abdominal pain). No serious safety concerns were identified in the reviewed studies.

Limitations

Evidence is limited by heterogeneity in probiotic strains, dosages, treatment durations, and study populations. Some clinical trials showed inconsistent or uncertain results. Many studies had small sample sizes or were pilot trials. More high-quality, standardized RCTs are needed to confirm strain-specific effects and long-term benefits. Data on some populations, such as solid organ transplant recipients and chronic kidney disease patients, are insufficient to draw conclusions.

PubMed sources