Supplement
Yeast mannan is a fiber-like carbohydrate from yeast cell walls that feeds gut microbes and interacts with immune cells in the gut. Most interest centers on immune function, where the evidence is limited: studies in fish, mice, and poultry found stronger innate immune responses and better reactions to infectious challenges. All of that work was in animals, and no human trials exist, so results may not carry over to people.
Sources: PMID 17766145; PMID 29723205
- Updated
- How we grade
- 7 studies cited
- Best evidence
- Grade C
- Conditions studied
- 2
- Outcomes
- 4
- Graded outcomes
- 0013
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
General
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Gut Microbiome Composition An in vitro canine gastrointestinal model found dried yeast cell walls high in beta-glucan and MOS positively affected microbial composition and fermentation activity. Additional poultry studies showed effects on jejunal gene expression and gut morphology, supporting prebiotic activity across species. | Improves (the measure goes up) | Small effect | 3 studies | |||
Studies that measured gut microbiome composition
| ||||||
| Gut Barrier Integrity In European sea bass, dietary MOS significantly reduced gut bacterial translocation, suggesting improved intestinal barrier function. Broiler chicken studies also showed improved gut morphology with MOS supplementation, though no human data exist. | Improves (the measure goes up) | Small effect | 2 studies | |||
Studies that measured gut barrier integrity
| ||||||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Infection Resistance In European sea bass, MOS feeding improved survival following pathogen challenge. A broiler chicken study demonstrated improved responses to Salmonella typhimurium challenge with dietary yeast cell wall components including MOS. Evidence is limited to animal models. | Improves (the measure goes up) | Small effect | 2 studies | |||
Key findings
- Immune FunctionImproves (the measure goes up)
- Gut Microbiome CompositionImproves (the measure goes up)
- Gut Barrier IntegrityImproves (the measure goes up)
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- Grade C
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Studies cited
7 studies from PubMed
- Comparative effects of Saccharomyces cerevisiae, mannan-oligosaccharides, and their synbiotic on growth performance, gut morphology, immune responses, and economic efficiency in broiler chickens.
- Response of broiler chickens to dietary different yeast cell wall components challenged with Salmonella typhimurium.
- Dried yeast cell walls high in beta-glucan and mannan-oligosaccharides positively affect microbial composition and activity in the canine gastrointestinal tract in vitro.
- Dietary yeast-derived mannan oligosaccharides have immune-modulatory properties but do not improve high fat diet-induced obesity and glucose intolerance.
- Effects of yeast cell wall-derived mannan-oligosaccharides on jejunal gene expression in young broiler chickens.
- Reduced gut bacterial translocation in European sea bass (Dicentrarchus labrax) fed mannan oligosaccharides (MOS).
- Immune stimulation and improved infection resistance in European sea bass (Dicentrarchus labrax) fed mannan oligosaccharides.