Probiotics are essential for human physiological health. You will want to supplement with many different types. One key type is Lactobacillus salivarius (L. salivarius).
You will find several different types of Lactobacillus in probiotics. L salivarius has the following helpful effects on human physiology according to the research.
Increases NK cells (natural killer)
Increases plasma levels of IgM, IgA and IgG (essential antibodies)
Improves gut microbiota balance in adults-that is has been shown to be inhibitory to pathogenic bacteria