Saccharomyces Boulardii for Diarrhea: Does It Really Work?

Key Findings

The meta-analysis found no significant reduction in diarrhea duration or the risk of diarrhea lasting ≥48 hours when using probiotics, including Saccharomyces boulardii, in studies with low risk of bias. While probiotics were associated with shorter hospitalization durations (MD -18.03 hours, 95% CI -27.28 to -8.78), this result was highly heterogeneous (I²=96%). No differences were observed in hospitalization rates, prolonged diarrhea (≥14 days), or adverse events. Evidence certainty was rated as moderate to very low due to methodological limitations and inconsistency.

Study Design

• Type: Cochrane meta-analysis of randomized controlled trials (RCTs).
• Sample Size: 82 studies (12,127 participants: 11,526 children, 412 adults; 3 studies included mixed-age groups without specifying numbers).
• Duration: Not explicitly stated; studies focused on acute infectious diarrhea (typically <14 days).
• Methodology: Trials compared probiotics (including S. boulardii) to placebo or no probiotic. Data were pooled using random-effects models. Subgroup analyses included Lactobacillus rhamnosus GG and S. boulardii.

Dosage & Administration

The summary does not specify exact doses or administration methods for S. boulardii or other probiotics. Variability in probiotic strains, dosages, and formulations across studies was noted, but details were not provided in the extracted text.

Results & Efficacy

• Primary Outcomes:
• Risk of diarrhea lasting ≥48 hours: No difference (RR 1.00, 95% CI 0.91–1.09; 2 trials, 1,770 participants; moderate-certainty evidence).
• Diarrhea duration: Uncertain effect (MD 8.64 hours shorter, 95% CI -29.4 to +12.1; 6 trials, 3,058 participants; very low-certainty evidence).
• Secondary Outcomes:
• Hospitalization duration (inpatient studies): Shorter by 18.03 hours (I²=96%; 24 trials, 4,056 participants).
• Prolonged diarrhea (≥14 days): No difference (RR 0.49, 95% CI 0.16–1.53; 9 studies, 2,928 participants).
• Hospitalization rates (community studies): No difference (RR 1.26, 95% CI 0.84–1.89; 6 studies, 2,283 participants).
• Subgroup Analyses: Similar effect sizes for L. rhamnosus GG and S. boulardii, with persistent heterogeneity.

Limitations

1. High Risk of Bias: Many studies had unclear or high bias across domains (e.g., blinding, randomization).
2. Statistical Heterogeneity: Marked inconsistency in results (e.g., I²=96% for hospitalization duration), unexplained by participant age, rotavirus status, or antibiotic use.
3. Publication Bias: Funnel plots indicated asymmetry, suggesting possible selective reporting.
4. Lack of Specific Data: No detailed subgroup analysis for S. boulardii alone; dosages and formulations were not standardized.
5. Geographic Variability: Most trials (53/82) were conducted in low-mortality countries, limiting generalizability to high-risk populations.

Clinical Relevance

For supplement users, this analysis suggests that probiotics like S. boulardii may not reliably reduce diarrhea duration or prevent prolonged illness in acute infectious cases, particularly in well-conducted trials. While shorter hospital stays were observed, the high heterogeneity and lack of standardized dosing make this finding uncertain. The absence of serious adverse events supports safety, but clinicians should weigh these results against the study’s limitations. Further research with consistent methodologies, specific probiotic strains, and diverse populations is needed to clarify efficacy. Users in low-mortality regions may see minimal benefit, whereas effects in high-mortality settings remain unclear.

Source: PubMed (Cochrane Database Syst Rev, 2020).