Characteristics and health benefits of the probiotic yeast Saccharomyces boulardii

Saccharomyces boulardii is a well-established probiotic yeast with documented clinical benefits for gastrointestinal health. This review highlights the key biotherapeutic mechanisms underlying its protective effects, with particular emphasis on its bioactive metabolites, including specialized enzymes, polyamines, organic acids, and vitamins. These postbiotic factors contribute to epithelial barrier reinforcement, immune modulation, and pathogen exclusion, thereby promoting intestinal homeostasis. In addition, S. boulardii supports microbial equilibrium through colonization resistance and regulation of inflammatory signaling pathways, including nuclear factor kappa-light-chain-enhancer of activated B cells. Clinical evidence demonstrates its efficacy in the prevention and management of antibiotic-associated diarrhea, inflammatory bowel disease, and irritable bowel syndrome. Safety considerations are also addressed, noting its biological distinction from Saccharomyces cerevisiae, particularly its inability to undergo hyphal transformation. Owing to its resilience against gastric acidity, bile salts, and concomitant antibiotic therapy, S. boulardii represents a valuable adjunct in contemporary gastrointestinal therapeutics and a promising platform for functional and translational applications.