Across 5 review studies, all reported beneficial effects on immune function with predominantly moderate effect sizes. However, all studies were narrative reviews without quantitative synthesis, and none reported statistically significant findings. Doses and specific populations varied or were not specified.
Caveats: All 5 studies are narrative reviews without quantitative meta-analysis. None reported statistically significant results. Evidence is based on indirect or in vitro findings. Heterogeneity in populations (animal, human, in vitro) limits applicability.
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.