The use of as potential therapeutic intervention is receiving increasing attention. Health benefits attributed to this bacterium include an improvement of metabolic disorders and exerting anti-inflammatory effects. The abundance of is associated with a healthy gut in early mid- and later life. However, the effects of on a decline in intestinal health during the aging process are not investigated yet. We supplemented accelerated aging mice with for 10 weeks and investigated histological, transcriptional and immunological aspects of intestinal health. The thickness of the colonic mucus layer increased about 3-fold after long-term supplementation and was even significantly thicker compared to mice supplemented with WCFS1. Colonic gene expression profiles pointed towards a decreased expression of genes and pathways related to inflammation and immune function, and suggested a decreased presence of B cells in colon. Total B cell frequencies in spleen and mesenteric lymph nodes were not altered after supplementation. Mature and immature B cell frequencies in bone marrow were increased, whereas B cell precursors were unaffected. These findings implicate that B cell migration rather than production was affected by supplementation. Gene expression profiles in ileum pointed toward a decrease in metabolic- and immune-related processes and antimicrobial peptide production after supplementation. Besides, decreased the frequency of activated CD80 CD273 B cells in Peyer's patches. Additionally, the increased numbers of peritoneal resident macrophages and a decrease in Ly6C monocyte frequencies in spleen and mesenteric lymph nodes add evidence for the potentially anti-inflammatory properties of . Altogether, we show that supplementation with prevented the age-related decline in thickness of the colonic mucus layer and attenuated inflammation and immune-related processes at old age. This study implies that supplementation can contribute to a promotion of healthy aging.