# Saccharomyces boulardii CBS 5926

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/saccharomyces-boulardii-cbs-5926
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-04-03
**Evidence Score:** 2 / 10
**Category:** Fermented/Probiotic
**Also Known As:** S. boulardii CBS 5926, Saccharomyces cerevisiae var. boulardii CBS 5926, CBS 5926 strain, Boulard yeast CBS 5926, S. cerevisiae boulardii CBS 5926

## Overview

Saccharomyces boulardii CBS 5926 is a probiotic yeast strain that produces serine protease and phosphatase enzymes to neutralize bacterial toxins and modulate gut mucosal [immunity](/ingredients/condition/immune-support). Its primary mechanism involves secreting 54 kDa protease that cleaves Clostridioides difficile toxin A receptors and stimulating secretory IgA production to reinforce [intestinal barrier integrity](/ingredients/condition/gut-health).

## Health Benefits

• Supports intestinal epithelial regeneration (referenced in PMID 26316791, though specific study details not provided)
• May help prevent diarrhea (general strain evaluated in over 90 randomized clinical trials per research, though specific CBS 5926 trial details absent)
• Evidence quality: Insufficient specific clinical data provided for CBS 5926 strain
• Individual study designs, sample sizes, and outcomes not detailed in available research
• Comprehensive efficacy data for this specific strain lacking in provided sources

## Mechanism of Action

S. boulardii CBS 5926 secretes a 54 kDa serine protease that proteolytically cleaves toxin A from Clostridioides difficile, reducing enterocyte damage, and a 63 kDa phosphatase that dephosphorylates lipopolysaccharide to blunt TLR4-mediated NF-κB [inflammatory](/ingredients/condition/inflammation) signaling. The strain upregulates intestinal secretory IgA and stimulates release of polyamine spermidine and spermine, which accelerate enterocyte proliferation and tight junction protein expression including claudin-3 and ZO-1. Additionally, it competitively excludes pathogens by adhering to mannose receptors on intestinal epithelial cells via yeast surface mannoproteins.

## Clinical Summary

The broader S. boulardii species has been evaluated in over 90 randomized controlled trials covering indications including antibiotic-associated diarrhea, traveler's diarrhea, and Clostridioides difficile infection, with meta-analyses showing a relative risk reduction of approximately 51% for antibiotic-associated diarrhea at doses of 250–500 mg daily. Specific CBS 5926 strain-level RCT data remain limited, making it difficult to isolate strain-specific efficacy from pooled Saccharomyces boulardii findings. One referenced study (PMID 26316791) supports intestinal epithelial regeneration activity, though sample size and quantified outcomes for this specific strain are not fully disclosed. Overall evidence quality is moderate to low for CBS 5926 specifically, and consumers should distinguish strain-specific claims from class-level [probiotic](/ingredients/condition/gut-health) research.

## Nutritional Profile

Saccharomyces boulardii CBS 5926 is a probiotic yeast strain, not a traditional food ingredient, so its nutritional profile differs from conventional macronutrient sources. Per standard lyophilized dose (250–500 mg, typically delivering ~5×10⁹ CFU): Protein content approximately 40–50% of dry cell mass (yeast cell wall and cytoplasmic proteins, including heat shock proteins and enzymes); Carbohydrates approximately 35–45% of dry mass, predominantly as beta-1,3/1,6-glucans (~30–35% of cell wall polysaccharides) and mannoproteins (~30–40% of cell wall); Fat/lipid content approximately 4–7% of dry mass, including ergosterol (yeast-specific sterol, precursor to vitamin D2, ~0.3–1.0 mg per gram dry weight) and phospholipids. Bioactive compounds include secretory IgA-stimulating mannoproteins, a 54 kDa serine protease capable of cleaving Clostridioides difficile toxins A and B, zinc-carboxypeptidase enzyme activity, and polyamines (spermidine, spermine) which support intestinal epithelial renewal. B-vitamins are present in modest amounts within yeast cell mass, including riboflavin (B2, ~0.04 mg/g dry weight), niacin (B3, ~0.3–0.5 mg/g dry weight), and folate traces. Zinc is present at approximately 0.05–0.15 mg per standard dose. Bioavailability of cellular constituents is limited given the intact cell wall structure; however, secreted enzymes and metabolites are directly bioavailable in the intestinal lumen. CBS 5926 is temperature-sensitive above 37°C and is distinct from Saccharomyces cerevisiae in its thermotolerance profile up to 37°C and resistance to standard antifungal agents used in [gut microbiome](/ingredients/condition/gut-health) studies.

## Dosage & Preparation

No clinically studied dosage ranges, forms, or standardization details (such as CFU counts) are specified in the available research for Saccharomyces boulardii CBS 5926. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

S. boulardii CBS 5926 is generally well tolerated in immunocompetent adults, with the most common adverse effects being mild bloating and flatulence at doses above 500 mg daily. Because it is a live yeast, it is contraindicated in severely immunocompromised individuals, those with central venous catheters, and patients with a history of fungemia, due to rare but documented cases of Saccharomyces fungemia in these populations. It should not be co-administered with antifungal medications such as fluconazole or itraconazole, which will inactivate the [probiotic](/ingredients/condition/gut-health) and negate its therapeutic effect. Pregnancy and lactation safety data are insufficient; use in these populations should occur only under physician supervision.

## Scientific Research

While the research indicates S. boulardii CBS 5926 has been evaluated in over 90 randomized clinical trials, specific study details including designs, sample sizes, and outcomes are absent from the available data. Only one PMID (26316791) is referenced regarding intestinal epithelial regeneration support, but without comprehensive study information.

## Historical & Cultural Context

Saccharomyces boulardii CBS 5926 has no documented historical use in traditional medicine systems. Its discovery in 1923 represents modern [probiotic](/ingredients/condition/gut-health) development rather than ancient therapeutic application.

## Synergistic Combinations

Lactobacillus acidophilus, Bifidobacterium bifidum, [Prebiotic](/ingredients/condition/gut-health)s (FOS/GOS), Zinc, L-glutamine

## Frequently Asked Questions

### What is Saccharomyces boulardii CBS 5926 used for?

Saccharomyces boulardii CBS 5926 is used primarily to support gastrointestinal health, including reducing diarrhea associated with antibiotic use and promoting intestinal epithelial regeneration. It produces serine proteases that neutralize bacterial toxins such as Clostridioides difficile toxin A, making it relevant for gut barrier protection. Strain-specific clinical trial data are limited, so its use is largely informed by broader S. boulardii research.

### What is the recommended dosage for Saccharomyces boulardii CBS 5926?

Based on general S. boulardii clinical research, effective doses typically range from 250 mg to 500 mg (approximately 5–10 billion CFU) taken one to two times daily with meals. Higher doses up to 1,000 mg daily have been used in some trials for active diarrheal conditions without significant additional adverse effects. No CBS 5926-specific dose-finding trials have been published, so these figures are extrapolated from broader Saccharomyces boulardii evidence.

### Can Saccharomyces boulardii CBS 5926 be taken with antibiotics?

Yes, S. boulardii CBS 5926 can be taken alongside antibacterial antibiotics because, as a yeast, it is not susceptible to antibacterial agents and retains viability during antibiotic courses. Meta-analyses of S. boulardii across multiple strains show roughly a 51% reduction in antibiotic-associated diarrhea risk when taken concurrently. However, it must never be combined with antifungal drugs like fluconazole or voriconazole, which will kill the yeast and eliminate its probiotic benefit.

### Is Saccharomyces boulardii CBS 5926 safe for immunocompromised patients?

Saccharomyces boulardii CBS 5926 is contraindicated in severely immunocompromised patients, including those undergoing chemotherapy, organ transplant recipients on high-dose immunosuppressants, and individuals with HIV/AIDS with low CD4 counts. Case reports document Saccharomyces fungemia in these populations, particularly in patients with central venous catheters where yeast translocation from the gut or environmental contamination can cause systemic infection. Immunocompromised individuals should consult a physician before using any live yeast probiotic.

### How does Saccharomyces boulardii CBS 5926 differ from Lactobacillus probiotics?

Unlike Lactobacillus species, which are gram-positive bacteria, S. boulardii CBS 5926 is a eukaryotic yeast with a cell wall composed of beta-glucans and mannoproteins, giving it unique mechanisms such as secreting proteases that directly degrade bacterial toxins—a capability bacteria-based probiotics lack. Its yeast nature also confers antibiotic resistance, allowing co-administration during antibiotic therapy without loss of viability. Additionally, S. boulardii survives gastric transit at a higher rate due to its thermotolerance and acid resistance compared to many Lactobacillus strains.

### What is the difference between Saccharomyces boulardii CBS 5926 and other Saccharomyces boulardii strains?

CBS 5926 is a specific strain designation that identifies a particular isolate of Saccharomyces boulardii registered with the Centraalbureau voor Schimmelcultures (CBS) collection. Different strains of the same species may have varying stability, viability, and clinical performance characteristics, making strain-specific identification important for supplement quality and consistency. The CBS 5926 designation ensures traceability and standardization in clinical and research applications.

### How long does it typically take to see results from Saccharomyces boulardii CBS 5926 supplementation?

Clinical effects from Saccharomyces boulardii typically emerge within the first few days to two weeks of supplementation, particularly for acute diarrhea prevention and intestinal support. However, the timeline may vary depending on individual digestive health, the specific condition being addressed, and consistency of use. For optimal results, consistent daily supplementation is generally recommended rather than occasional use.

### Does Saccharomyces boulardii CBS 5926 remain in the gut long-term or does it need to be taken continuously?

Saccharomyces boulardii, including the CBS 5926 strain, is a transient organism that does not establish permanent colonization in the human gut and is typically eliminated within days to weeks after supplementation stops. This means continuous or regular supplementation is necessary to maintain its benefits, rather than it providing long-term gut restoration like some bacterial probiotics. The transient nature is actually a safety advantage, as it reduces risk of overgrowth or adverse effects from prolonged colonization.

---

*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
*License: CC BY-NC-SA 4.0 — Attribution required. Commercial use: admin@hermeticasuperfoods.com*