VIP is antimicrobial toward certain bacteria and promotes the proliferation of beneficial gut bacteria. It also regulates both stomach acid secretion as well as water and ion absorption in the large intestine. Lastly, VIP aids proper peristalsis by inhibiting smooth muscle contraction and by triggering mucus secretion by Goblet cells. VIP can help control joint inflammation and can inhibit the destruction of cartilage and bone in arthritis. It functions as a macrophage-deactivating factor. This means it stops the production of pro-inflammatory cytokines (IL-1, IL-6,
IL-12) and tumor necrosis factor-α (TNF-α), while stimulating the production of anti-inflammatory cytokines such as IL-4, IL-10, IL-13.
