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saccharomyces boulardii

What does the research say about saccharomyces boulardii?

5 health outcomes synthesised

Research on Saccharomyces boulardii has investigated its effects across five health outcomes, with the strongest evidence supporting its use for reducing diarrhea. A synthesis of six studies found a consistent beneficial effect with moderate effect size, primarily in clinical populations such as patients undergoing pelvic radiotherapy or those with Helicobacter pylori infection. Doses in this body of research ranged from 250 mg/day to 2000 mg/day, with 500 mg four times daily and 250 mg/day being the most common regimens.

Strongest evidence: The most robust research supports Saccharomyces boulardii for reducing diarrhea, based on 6 studies with high evidence strength and a moderate effect size. Every study reported a beneficial outcome, though effect sizes varied from small to large across populations (radiotherapy patients, critically ill tube-fed patients, hospitalized patients, and those with H. pylori infection). For reducing diarrhea rate (7 studies, moderate evidence), 5 of 7 studies showed benefit with a moderate effect size, with doses of 250–500 mg twice daily. Three of 4 studies on reducing diarrhea duration showed small-to-moderate benefit in children with acute diarrhea.

Mixed or weaker evidence: For improved H. pylori eradication rates (4 studies, moderate evidence), 3 of 4 studies were beneficial with a small effect size, but one meta-analysis found no significant benefit, and the only neutral RCT reported a numerically higher rate that did not reach significance. All 3 studies on reducing stool frequency in children with acute diarrhea were beneficial, but effect sizes were mixed (small to large), and the evidence base is considered preliminary due to the small number of studies.

Effective dose patterns: Converging dose ranges appear across outcomes. For diarrhea outcomes, doses commonly studied include 250 mg once daily, 250 mg twice daily, and 500 mg four times daily (up to 2000 mg/day). For H. pylori eradication, 250 mg twice daily was used. The most consistently reported effective dose across multiple outcomes is 250–500 mg twice daily (500–1000 mg/day).

Population insights: The strongest evidence comes from clinical populations with diarrhea — patients undergoing pelvic radiotherapy, critically ill tube-fed patients, and those with H. pylori infection. For reducing diarrhea rate and duration, children with acute diarrhea are the most-studied population. Adults with H. pylori infection, including those with previous treatment failure, are the primary population for eradication outcomes.

Notable caveats: Publication bias is a significant concern across all outcomes — null-result studies are less likely to be published or indexed. Study durations were not consistently reported in the diarrhea research, limiting conclusions about time to effect. Several studies had small sample sizes, and effect sizes varied considerably across populations. Dose and form reporting was incomplete in several studies, particularly for diarrhea rate and duration outcomes. The evidence base for stool frequency and H. pylori eradication is small (3–4 studies) and should be considered preliminary.

Frequently asked

  • What is Saccharomyces boulardii good for according to research?
    The strongest and most consistent research supports Saccharomyces boulardii for reducing diarrhea, with 6 of 6 studies showing benefit (high evidence strength) and 5 of 7 studies showing reduced diarrhea rates (moderate evidence). Evidence also suggests small benefits for reducing diarrhea duration in children and improving H. pylori eradication rates, though these are based on fewer studies with smaller effect sizes.
  • What dose of Saccharomyces boulardii is typically used in studies?
    Doses vary by outcome but commonly fall between 250 mg/day and 2000 mg/day. The most frequent regimens are 250 mg once daily, 250 mg twice daily (500 mg/day), and 500 mg four times daily (2000 mg/day). For diarrhea outcomes, 250–500 mg twice daily is the most consistently reported effective range across multiple studies.
  • Who benefits most from Saccharomyces boulardii?
    Clinical populations with diarrhea show the strongest evidence — patients undergoing pelvic radiotherapy, critically ill tube-fed patients, hospitalized patients, and those with Helicobacter pylori infection. Children with acute diarrhea are the most-studied group for reducing diarrhea rate, duration, and stool frequency. Adults with H. pylori infection, including those with previous treatment failure, are the primary population studied for eradication outcomes.
  • Are there caveats or limitations in the research on Saccharomyces boulardii?
    Yes. Publication bias is a concern across all outcomes — null-result studies are less likely to be published. Several studies had small sample sizes, and effect sizes varied from small to large across different populations. Study durations were not consistently reported for diarrhea outcomes. Dose and form reporting was incomplete in some studies, and the evidence bases for H. pylori eradication and stool frequency are small (3–4 studies), making conclusions preliminary.
  • Does Saccharomyces boulardii help with H. pylori eradication?
    Three of 4 studies reported a beneficial effect on H. pylori eradication rates, but the overall effect size is small. One meta-analysis found no significant benefit, and one RCT showed a numerically higher eradication rate that did not reach statistical significance. The evidence is moderate in strength but considered preliminary due to the small number of studies and inconsistent findings.
  • How strong is the evidence for Saccharomyces boulardii reducing diarrhea in children?
    For reducing diarrhea rate, 5 of 7 studies showed benefit in children and other populations, with moderate evidence strength and moderate effect size. For reducing diarrhea duration, 3 of 4 studies showed benefit in children, but effect sizes ranged from small to moderate. For reducing stool frequency, all 3 studies in children showed benefit, but effect sizes were mixed and the evidence base is small. Overall, the pediatric evidence is positive but varies in strength depending on the specific outcome.
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