Immune System Biotix is an exciting new formula from Quest Vitamins; it is a unique combination of nutrients that contribute to the normal function of the immune system. This high potency formula includes beta glucans from yeast, aged garlic, vitamin D, the minerals, selenium, zinc and copper along with probiotic bacteria. Beta Glucans are potent biologically active molecules found in the cell walls of oats, fungi or yeast. Immune System Biotix contains the most active form of beta glucans with both beta (1-3) and (1-6) linkages. Aged garlic extract has been shown to support various immune factors. Vitamin D, selenium, zinc and copper each play a role in the normal functioning of the immune system, each capsule of Immune System Biotix provides 1000iu of vitamin D.