Xylooligosaccharides (XOS) are prebiotic fibers that have been researched for their effects on the gut-associated lymphoid tissue, including Peyer’s patches, which are critical components of the immune system located in the small intestine. Scientific studies, primarily in animal models, have shown that XOS can modulate the gut microbiota, leading to increased production of short-chain fatty acids (SCFAs) and improvements in mucosal immunity. Notably, several studies have demonstrated that dietary XOS supplementation can increase the size and activity of Peyer’s patches, enhance IgA secretion, and stimulate the proliferation of beneficial immune cells such as T and B lymphocytes within these lymphoid structures (e.g., Chen et al., 2016, Journal of Agricultural and Food Chemistry).

The proposed mechanism involves XOS being fermented by gut bacteria, leading to metabolites that interact with immune cells in the gut mucosa, ultimately supporting the function of Peyer’s patches. However, while animal data is promising, direct evidence in humans remains limited, and most clinical studies focus on general gut health and immune modulation rather than specific effects on Peyer’s patches. In summary, there is moderate scientific support—primarily from preclinical research—that XOS can support the immune functions of Peyer’s patches, but more robust human data are needed for a higher evidence rating.