Saccharomyces boulardii is a probiotic yeast widely studied for its beneficial effects on gastrointestinal health, particularly in the prevention and treatment of diarrhea and certain inflammatory conditions. The Peyer’s patches are important immune structures in the small intestine that play a crucial role in mucosal immunity by sampling antigens and facilitating the generation of immune responses. Scientific evidence suggests that S. boulardii can modulate immune functions associated with the gut, including activity within Peyer’s patches.

Several animal studies have demonstrated that oral administration of S. boulardii can increase secretory IgA production and modulate cytokine responses, which are processes linked to Peyer’s patch activation and function. For example, research has shown that S. boulardii can stimulate dendritic cells and enhance the expression of anti-inflammatory cytokines in the gut mucosa. These effects are believed to contribute to the yeast’s ability to protect against enteric pathogens and reduce gut inflammation. However, the direct evidence in humans regarding specific effects on Peyer’s patches is limited; most studies assess broader immune markers or clinical endpoints like diarrhea incidence.

In summary, while there is scientific rationale and some preclinical evidence supporting the use of S. boulardii to modulate immune functions linked to Peyer’s patches, direct clinical evidence is moderate, leading to a rating of 3 out of 5 for this specific application.