Effect of Saccharomyces boulardii on sIgA Levels in Stool
Saccharomyces boulardii significantly increases secretory IgA (sIgA) levels in stool by stimulating intestinal immune responses. 1
Mechanism of Action
S. boulardii stimulates the secretion of secretory IgA (sIgA) and secretory component of immunoglobulins in the small intestine, with studies showing approximately 57% increase in sIgA concentration in the duodenal fluid of treated subjects 1
The probiotic yeast enhances the secretory component (SC) content in crypt cells isolated from the jejunum (48.5% increase) and in duodenal fluid (62.8% increase) compared to controls 1
S. boulardii activates the RAS-GAP-RAF-ERK(1,2) pathway with participation of growth receptor bound 2 protein, which contributes to its trophic effects on intestinal mucosa 2
The probiotic generates mitogen and metabolic signals that are transduced into intestinal mucosal cells, affecting immune function and barrier integrity 2
Clinical Relevance
The increased sIgA production contributes to S. boulardii's protective effects against enteric pathogens and antibiotic-associated diarrhea 3
S. boulardii releases a 54-kDa protease that digests Clostridium difficile toxins A and B and their brush border membrane receptors, providing protection against C. difficile-induced inflammatory diarrhea 4
The American Gastroenterological Association conditionally recommends S. boulardii for prevention of C. difficile infection in patients receiving antibiotics, with evidence showing a 59% reduction in C. difficile-associated diarrhea recurrence compared to placebo 5
S. boulardii has been found to be significantly efficacious and safe in 84% of randomized, placebo-controlled treatment arms across 27 trials involving 5029 patients 3
Dosing and Administration
Effective dosing in clinical studies typically involves 1g or 3×10¹⁰ CFU/day of S. boulardii 5
For maximum benefit, S. boulardii should be started at the beginning of antibiotic therapy and continued throughout the entire course of treatment 5
Important Considerations and Cautions
S. boulardii is contraindicated in immunocompromised patients due to the risk of fungemia 5
The overall quality of evidence supporting S. boulardii's effects on intestinal immune function is rated as low to moderate 5
While S. boulardii shows promise for various gastrointestinal conditions, its specific effect on sIgA levels should be considered as part of its broader immunomodulatory actions 6