Across all 5 studies, all (100%) reported beneficial effects on immune function, with effect sizes ranging from small to moderate. The evidence is entirely from review articles, generally discussing probiotics including Bifidobacterium plantarum, rather than from direct interventional trials. No specific dose, form, or duration data were reported in these studies.
Caveats: Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. Evidence base is small (only 5 studies) — conclusions should be considered preliminary. All studies are reviews, not original clinical trials; no specific dose, duration, or form was reported. Some studies were conducted in animal populations (livestock, poultry) and may not generalize to humans.
and increases immunity
They enhance antioxidant enzymes... promote the maturation and function of immune cells, and increasing secretory IgA production.
In vitro studies indicate that probiotics can activate immune cells like peripheral blood mononuclear cells (PBMCs), NK cells, T cells, and antigen-presenting cells to help fight tumors.
Their interaction with the immune system plays a crucial role in offering protection and therapeutic effects, particularly in enhancing immunity in older adults.
Probiotics, such as Lactobacillus, Bifidobacterium, and Saccharomyces, modulate the gut microbiota, enhance the gut barrier, and regulate the immune system.