About Saccharomyces boulardii
One of the most studied probiotics in existence with 100+ RCTs and multiple meta-analyses. A non-pathogenic yeast (not a bacterium), inherently acid- and bile-resistant, which colonizes transiently and clears within 3–5 days of cessation. Strongest evidence is for antibiotic-associated diarrhea (AAD) prevention: Szajewska & Kolodziej 2015 meta-analysis of 21 RCTs found RR 0.47 (95% CI 0.38–0.57), NNT of 10. Also studied for C. difficile recurrence prevention, acute diarrhea, traveler's diarrhea, IBS, and H. pylori therapy side effect reduction. The CNCM I-745 strain (Biocodex/Florastor) is the reference strain used in the vast majority of clinical trials. Contraindicated in severely immunocompromised patients (rare case reports of fungemia in ICU patients with central venous catheters). No RDA or UL established.
What Saccharomyces boulardii supports
- Strong evidence for preventing antibiotic-associated diarrhea
- Supports gut barrier function and immune modulation
- May reduce side effects during H. pylori eradication therapy
How much Saccharomyces boulardii to take
The RDA prevents deficiency. The effective range is what clinical trials used to actually move the outcome.
Effective
500–1000
mg
500–1000 mg/day (250–500 mg BID) used in most RCTs. 250 mg CNCM I-745 ≈ 2.5 billion CFU. Szajewska & Kolodziej 2015 meta-analysis (21 RCTs): RR 0.47 for AAD prevention.
Clinical evidence
Strong clinical evidence. 100+ RCTs; Szajewska 2015 meta-analysis (21 RCTs): RR 0.47 for AAD; McFarland 2010 meta-analysis (27 RCTs); Cochrane reviews confirm efficacy
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