Role of vitamins D, E and C in immunity and inflammation.

Inflammatory responses are operationally characterized by pain, redness, heat and swelling at the site of infection and trauma. Mast cells reside near small blood vessels and, when activated, release potent mediators involved in allergy and inflammation. Vitamin D modulates contraction, inflammation and remodeling tissue. Vitamin D deficiency has been linked to multiple diseases and several data have demonstrated a strong relationship between serum vitamin D levels and tissue function. Therapy targeting vitamin D3 signaling may provide new approaches for infectious and inflammatory skin diseases by affecting both innate and adaptive immune functions. Mast cells are activated by oxidized lipoproteins, resulting in increased expression of inflammatory cytokines and suggesting that the reduction of oxidation of low density lipoprotein by vitamin E may also reduce mast cell activation. Vitamin C is also an anti-oxidant well-known as an anti-scurvy agent in humans. Vitamin C inhibits peroxidation of membrane phospholipids and acts as a scavenger of free radicals and is also required for the synthesis of several hormones and neurotransmitters. In humans, vitamin C reduces the duration of common cold symptoms, even if its effect is not clear. Supplementation of vitamin C improves the function of the human immune system, such as antimicrobial and natural killer cell activities, lymphocyte proliferation, chemotaxis and delayed-type hypersensitivity. Vitamin C depletion has been correlated with histaminemia which has been shown to damage endothelial-dependent vasodilation. However, the impact of these vitamins on allergy and inflammation is still not well understood.