Saccharomyces cerevisiae
Also known as: Saccharomyces cerevisiae, Baker’s yeast, Brewer’s yeast, Live yeast
Overview
Saccharomyces cerevisiae is a yeast species widely utilized in baking, brewing, and as a probiotic supplement. It is naturally found on fruits, grains, and in fermentation environments. Primarily, it serves as a probiotic in both human and animal nutrition, enhancing gut health and digestion, and improving performance metrics like growth and milk production in livestock. This live yeast modulates gut microbiota, enhances fermentation, and improves nutrient absorption. Research maturity is moderate to high, with numerous randomized controlled trials (RCTs) and meta-analyses, especially in animal nutrition. Evidence is robust in animal studies for growth and production benefits, while human clinical evidence is more limited, often focusing on the related species Saccharomyces boulardii. It is available in various forms, including live yeast cultures in feed or feed additives.
Benefits
In ruminant animals like goats and cattle, S. cerevisiae supplementation improves growth performance, rumen fermentation, and milk yield. A meta-analysis of 44 studies demonstrated a statistically significant moderate effect size (Hedges’ d = 0.240, 95% CI: 0.142–0.339, p < 0.001) on milk yield and components. Another meta-analysis reported positive effects on dry matter intake and average daily gain in beef cattle. Improvements in haemato-biochemical indices and ruminal fermentation parameters have also been observed in goats. These benefits accrue over weeks to months of supplementation. Human data on S. cerevisiae specifically is limited; more evidence exists for the closely related S. boulardii strain in human gastrointestinal conditions.
How it works
Saccharomyces cerevisiae enhances ruminal microbial fermentation by stabilizing pH and promoting beneficial microbial populations. In ruminants, it improves digestion efficiency and nutrient absorption via modulation of rumen microbiota. Its effects are primarily indirect, influencing microbial enzymatic activity and fermentation pathways rather than direct molecular receptor binding. As a live yeast, it acts locally in the gastrointestinal tract rather than being absorbed systemically. The viability of the yeast is crucial for its efficacy in modulating the gut environment.
Side effects
Saccharomyces cerevisiae is generally recognized as safe (GRAS) in both human and animal use. Common side effects are rare in animals, with no significant adverse effects reported in meta-analyses. Uncommon side effects are not well documented; yeast intolerance or allergy is rare. In immunocompromised humans, there is a rare risk of fungemia with related strains, though this is not common with S. cerevisiae. No significant drug interactions have been reported. Caution is advised in immunocompromised individuals for related yeast probiotics. Most data pertains to animals; human use should consider strain specificity and clinical context.
Dosage
Dosage varies by species and formulation; animal studies typically use doses standardized to colony-forming units (CFU) in feed. Optimal dosage ranges are not standardized, but meta-analyses include a range of doses with positive effects observed across typical commercial supplementation levels. No toxicity has been reported at typical supplementation levels in animals. Continuous supplementation is common during growth or lactation phases in animals. It is typically administered as live yeast cultures in feed or feed additives. As it acts locally in the gut, viability of the yeast is important for efficacy. No specific cofactors are required; it works synergistically with dietary substrates.
FAQs
Is Saccharomyces cerevisiae safe for humans?
Generally safe, but most human probiotic research focuses on S. boulardii, a related strain. S. cerevisiae is widely used in food but less studied as a human probiotic.
How quickly do benefits appear?
In animals, benefits typically appear within weeks of supplementation.
Can it be used alongside antibiotics?
Yeast probiotics like S. boulardii are often used to prevent antibiotic-associated diarrhea; S. cerevisiae’s role is less defined in humans.
Does it survive stomach acid?
Live yeast can survive passage through the stomach to exert effects in the gut.
Research Sources
- https://pubmed.ncbi.nlm.nih.gov/36923902/ – This meta-analysis of dietary S. cerevisiae in goats demonstrated positive effects on growth performance, haemato-biochemical indices, and ruminal fermentation. The study included multiple studies with rigorous methodology, confirming beneficial effects on animal health and productivity.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC2868213/ – This systematic review/meta-analysis focuses on Saccharomyces boulardii and demonstrates strong evidence for its efficacy in preventing antibiotic-associated diarrhea and other gastrointestinal conditions. It highlights the probiotic potential of Saccharomyces species in humans, although it focuses on a different strain.
- https://www.degruyterbrill.com/document/doi/10.1515/opag-2022-0178/html – This research explores the effects of Saccharomyces cerevisiae on milk yield and composition in dairy animals. The meta-analysis included 44 studies and 59 comparisons, showing a statistically significant moderate effect size for milk yield improvement, indicating a consistent benefit.
- https://researcherslinks.com/current-issues/Unlocking-Insights-into-Saccharomyces-cerevisiae/33/1/9731/html – This study investigates the impact of Saccharomyces cerevisiae on rumen fermentation and overall health in livestock. The findings suggest that S. cerevisiae can enhance rumen function, leading to improved nutrient utilization and animal well-being.
- https://ccsenet.org/journal/index.php/jas/article/view/65841 – This article evaluates the effects of live yeast supplementation on dry matter intake and average daily gain in beef cattle. The results confirm positive impacts on growth performance with adequate sample sizes and controls, supporting the use of S. cerevisiae in beef cattle diets.
Supplements Containing Saccharomyces cerevisiae
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