Bifidobacterium Lactis for Immune Function

Research suggests that Bifidobacterium lactis may support several aspects of immune function, with evidence drawn from mouse studies, cell-based laboratory models, small randomized controlled trials in healthy adults and elderly populations, and a small number of infant studies. Across these sources, consistent findings include enhanced phagocytic activity of immune cells, increased natural killer cell activity, improved secretory IgA levels in the gut, and shifts in inflammatory signaling proteins such as TNF-alpha and TGF-beta1, with one RCT in older adults also reporting increased interferon-alpha production after six weeks of supplementation. Studies indicate that effects may be particularly relevant in populations with less robust baseline immunity, such as older adults, infants, and those with compromised gut barriers, though a large trial in very preterm infants reported mixed findings and noted its primary outcome data were still pending at the time of publication. Limitations worth noting include the relatively small sample sizes in most human trials, the presence of industry funding in some studies, reliance on animal and cell models that may not translate directly to human outcomes, and the fact that several studies tested B. lactis in combination with other probiotic strains or prebiotics, making it difficult to isolate the effects of B. lactis alone.