Mannanoligosaccharides (MOS) are prebiotic fibers derived primarily from the cell walls of yeast, such as Saccharomyces cerevisiae. Their use to support the function of Peyer’s patches—specialized lymphoid tissues in the small intestine involved in immune surveillance—has been investigated in animal studies, particularly in the context of gut immunity.

Scientific evidence shows that MOS can modulate gut-associated lymphoid tissue (GALT) activity, which includes Peyer’s patches, mainly in animal models. Research suggests that MOS supplementation can increase the size and activity of Peyer’s patches, enhance the production of immunoglobulins (notably IgA), and improve intestinal immune responses (Spring, 2010; Roselli, 2005). The proposed mechanism is that MOS binds to pathogenic bacteria, preventing their adhesion to epithelial cells, and stimulates immune cells within the mucosa, including those in Peyer’s patches.

However, most evidence for MOS’s effects on Peyer’s patches comes from studies in livestock (e.g., pigs and poultry), with limited direct research in humans. While the immunomodulatory role of MOS is promising, particularly in animal health and production, the translation of these findings to human health is still preliminary. Therefore, the use of MOS to support Peyer’s patches is scientifically justified, but human evidence remains limited, warranting a moderate evidence rating.