Probiotics for IBS: Do They Really Help? (2023 Study)

meta-analysis PMID: 37541528

Quick Summary: A recent review of many studies suggests that some probiotics might help with Irritable Bowel Syndrome (IBS) symptoms like bloating and stomach pain. However, the research is still not strong enough to say for sure which probiotics work best.

What The Research Found

Researchers looked at 82 different studies involving over 10,000 people with IBS. They found:

Some probiotics may help: Certain strains of Escherichia coli and Lactobacillus plantarum showed some benefit in reducing overall IBS symptoms.

Not all probiotics are equal: Other probiotics, especially combinations of different strains, showed less clear benefits.

Probiotics seem safe: People taking probiotics didn't have more side effects than those taking a placebo (a sugar pill).

Study Details

Who was studied: Adults diagnosed with Irritable Bowel Syndrome (IBS).

How long: The studies varied in length, but the review looked at the results of many different studies.

What they took: Participants took different types of probiotics, including Escherichia coli, Lactobacillus strains, and combinations. The doses and specific strains varied.

What This Means For You

Talk to your doctor: If you have IBS, discuss probiotics with your doctor. They can help you decide if they might be right for you.

Be patient: It might take some trial and error to find a probiotic that works for you, if any.

Look for specific strains: If you decide to try probiotics, consider those containing Escherichia coli or Lactobacillus plantarum, though the evidence is still limited.

Don't expect miracles: Probiotics may help some people, but they're not a guaranteed cure for IBS.

Consider other treatments: Probiotics are just one potential tool. Your doctor may recommend other treatments like dietary changes or medications.

Study Limitations

Not all studies are created equal: Some studies were better designed than others.

Different probiotics, different results: The studies used different types and doses of probiotics, making it hard to compare them.

More research is needed: The researchers said the evidence for probiotics was "low to very low" in many cases, meaning we need more high-quality studies to be sure.

Individual results vary: What works for one person might not work for another.

Key Findings

This meta-analysis of 82 randomized controlled trials (RCTs) involving 10,332 adults with irritable bowel syndrome (IBS) found that certain probiotic strains, particularly Escherichia coli Nissle 1917 and Lactobacillus plantarum 299V, showed moderate-to-low certainty evidence for reducing global IBS symptoms. Other strains, including combination probiotics and Bacillus species, demonstrated very low certainty of efficacy. No significant increase in adverse events was observed with probiotics compared to placebo (RR: 1.03, 95% CI 0.98–1.08). The authors concluded that while some probiotics may improve symptoms, the overall evidence quality was insufficient to make strong clinical recommendations.

Study Design

The study was a systematic review and meta-analysis of RCTs, with literature searches conducted up to March 2023 in MEDLINE, EMBASE, and the Cochrane Register. Trials included adults diagnosed with IBS and compared probiotics (any species/strain) to placebo. Outcomes included global symptoms, abdominal pain, bloating/distension, and adverse events. Data were pooled using relative risk (RR) for dichotomous outcomes and standardized mean difference (SMD) for continuous data. Only 24 of 82 trials were deemed low-risk of bias across all domains.

Dosage & Administration

The study summary did not specify exact dosages or administration protocols for probiotics across the included trials. Variability in strains, doses, and formulations was noted as a limitation, precluding standardized recommendations.

Results & Efficacy

Global Symptoms:
Escherichia strains (RR: 0.79, 95% CI 0.69–0.90; moderate certainty).
Lactobacillus plantarum 299V (RR: 0.85, 95% CI 0.74–0.98; low certainty).
Combination probiotics (RR: 0.90, 95% CI 0.83–0.97; very low certainty).
Abdominal Pain:
Saccharomyces cerevisiae I-3856 (RR: 0.84, 95% CI 0.73–0.97; low certainty).
Bifidobacterium strains (RR: 0.88, 95% CI 0.78–0.99; low certainty).
Bloating/Distension:
Combination probiotics (RR: 0.87, 95% CI 0.77–0.98; very low certainty).
Adverse Events: No significant difference between probiotics and placebo (RR: 1.03, 95% CI 0.98–1.08).

Limitations

Most analyses were graded as low-to-very low certainty by GRADE criteria due to heterogeneity in strains, dosages, and outcome measures. Only 24 trials had low risk of bias, and the remaining studies often lacked methodological rigor. Duration of treatment and follow-up periods were not standardized, and strain-specific effects were underreported. Adverse event data may be incomplete due to inconsistent reporting across trials.

Clinical Relevance

Supplement users with IBS should approach probiotics cautiously, as evidence for efficacy is weak and inconsistent. While E. coli Nissle 1917 and L. plantarum 299V show modest promise for global symptom relief, most products lack robust support. Probiotics appear safe, but individual responses may vary. Clinicians should prioritize strain-specific formulations and consider patient preferences until higher-quality trials clarify optimal dosing and species.