Your immune system is a complex network of organs, tissues and cells that works tirelessly to prevent infection by bacteria and viruses. A healthy immune system requires an ideal balance of many factors, including a diet rich in vitamins and nutrients.
Vitamin C or ascorbic acid is one of the most important immune-boosting vitamins you can get it from citrus fruits, berries and dark leafy vegetables.
Vitamin C
Vitamin C, also known as ascorbic acid, is a water-soluble nutrient that is essential for normal human growth and development. It is involved in a number of biological functions, including immune function.
B cells, which produce antibodies that bind to and neutralize invading viruses and bacteria, require vitamin C to differentiate, or change into their mature form. Additionally, phagocytes, a type of white blood cell that surrounds and digests invading pathogens, accumulate vitamin C and enhance chemotaxis, phagocytosis, generation of reactive oxygen species and microbial killing.
Researchers have found that patients with genetic disorders of neutrophil function, such as chronic granulomatous disease (CGD) and Chediak-Higashi syndrome, showed improved leukocyte chemotaxis following IV administration of vitamin C.
Vitamin A
Known collectively as B complex vitamins, the water-soluble B vitamins (thiamine, riboflavin, vitamin B3, vitamin B5, pantothenic acid, biotin and folate) are needed for energy metabolism. They can be found in foods and are also available as dietary supplements.
Vitamin A, a group of similar organic compounds that cannot be synthesized in the body, influences the immune system from foetal life and its deficiency can lead to serious complications. It acts as an antioxidant and its metabolites, retinoic acid and 1,25-dihydroxy vitamin D3, exhibit hormone-like effects.
Vitamin E, a group of eight related tocopherols and tocotrienols, is an anti-inflammatory nutrient. It decreases the production of reactive oxygen species by monocytes, decreases expression of adhesion molecules such as VCAM1 and ICAM1, and blocks the release of pro-inflammatory cytokines and chemokines by monocytes.
Vitamin E
Vitamin E is an antioxidant that protects cells from damage. It helps boost levels of a type of white blood cell called T lymphocytes, or T cells, which help the body fight infection.
Several studies in animal and human subjects have shown that vitamin E supplementation above current dietary recommendations improves immune function. This includes thymic T cell differentiation, lymphocyte proliferation, IL-2 production, and macrophage phagocytic activity.
These effects of vitamin E are mediated both directly via alterations to membrane integrity and signaling, and indirectly through modulation of inflammatory mediators produced by other immune cells. Emerging evidence indicates that non-tocopherol forms of vitamin E also have immunoregulatory functions.
Vitamin B6
Vitamin B6, also known as pyridoxine and pyridoxal 5’-phosphate (PLP), is an essential water-soluble vitamin involved in over 200 chemical reactions in the body. It plays a key role in producing antibodies, supporting red blood cell production, and helping the body absorb folate.
PLP is required for the conversion of tryptophan into niacin and for the metabolism of amino acids. It also helps control levels of homocysteine in the blood, which may be linked to heart disease. PL prevents excessive inflammation by inhibiting the accumulation of S1P and up-regulating the expression of anti-inflammatory genes, including IL-1b, TNF-a, IL-6, and NO. In addition, PL can suppress proliferation of macrophages by promoting autophagy.
Folate
Many of us seek specific foods or vitamins that are rumored to “boost immunity.” The truth is, our immune system depends on an ideal balance of many nutrients.
Folate, or vitamin B9, is needed for red blood cell formation and to build DNA (the genetic blueprint) in our cells. Folate can be found naturally in dark green vegetables, citrus fruits and beans, peas and nuts. It’s also added to some processed foods, such as flour and fortified cereals.
Vitamin E is an important antioxidant that reduces lipid peroxidation and free radical damage. It also enhances the immune response by promoting a Th1 cytokine mediated response and suppressing a Th2 cytokine mediated response.
Zinc
Zinc is necessary for many biological processes including cell growth, immune function, enzyme reactions, DNA synthesis and protein production. It is also essential for a healthy sense of taste and smell and plays a role in childhood growth and development.
Zinc deficiency affects innate myeloid immune cells and reduces phagocytosis and intracellular killing. It can also lead to a shift of the TH1/TH2 balance towards a TH1 response.
Zinc can also reduce the effects of aging on immune function and can help to increase the number of naive T cells. Zinc supplementation can also enhance antibody-mediated immune response against antigens. Zinc can also inhibit the activation of NF-kB in hepatocytes.