The role of the immune system is to prevent or limit infection caused by a pathogen. Immune system defends the body from foreign, invading organisms, promoting protective immunity while maintaining tolerance to self (1).

Immune system is divided into

• innate immunity
• adaptive immunity

The first defence which a pathogen comes across is innate immunity, which is a combination of physical and biochemical barriers with a non-specific, leukocyte-mediated cellular response to defend against pathogens.

If the pathogen escapes innate immunity a more complex, adaptive, antigen-specific response is triggered, mediated by T and B lymphocytes, which produces antibodies to kill the pathogen (2).

There are several factors which influence the immune system and its competence. One of the most important factors is food and nutrition. If the immune system is compromised a person’s natural defence is reduced and leads to infections.

If you are falling sick often it may be because your diet is deficient in certain nutrients which are required for proper functioning of your immune system. Some micronutrients (vitamins and minerals) are essential for the proper functioning of the immune system.

Vitamins needed for immune system

Several vitamins are needed for immune system especially

• vitamin A
• vitamin C
• vitamin D
• vitamin E
• folic acid

Vitamin C

Vitamin C is a water-soluble vitamin which has an effect on a host immune system and is the most potent physiological antioxidant. It protects us against free radicals produced when pathogens are destroyed by immune cells. Vitamin C is involved in the production of leukocytes which are involved in immune system. It has the capacity to increase serum antibodies (2).

Vitamin A

Vitamin A is a fat-soluble vitamin and is also known as retinol. Vitamin A has been shown to have a therapeutic effect in the treatment of various infectious diseases (3). Vitamin A is also known as an anti-inflammation vitamin as it plays a vital role in improving immune function. Vitamin A demonstrates both promoting and regulatory roles in the innate immune system and adaptive immunity. It provides an enhanced protection against multiple infectious diseases.

Vitamin D

Vitamin D is a fat-soluble vitamin and is primarily involved with calcium absorption and utilization in the body. Vitamin D plays an important role in modulation of the innate and adaptive immune responses. Vitamin D deficiency is seen in autoimmune disease and supplementing with vitamin D shows beneficial effects (1).

Vitamin E

Tocopherols are the major group of compounds with vitamin E biological activity. They are fat-soluble and are potent antioxidants. Vitamin E because of its antioxidant property protects the integrity of cell membranes from damage caused by free radicals (2). Supplementation with vitamins having antioxidant activity such as vitamin E has been associated with an enhancement of immune function (4).

Folic acid

Folic acid is a water-soluble B vitamin. Folic acid helps maintain innate immunity (2).

In situations where there is deficiency of these vitamins the immune system will be compromised. Make sure your diet supplies these micronutrients in adequate quantities. Include plenty of fruits, vegetables and whole grains in your diet as part of a balanced diet.

References

1. Aranow, C. (2011). Vitamin D and the immune system. Journal of investigative medicine: the official publication of the American Federation for Clinical Research, Vol.59(6) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/

2. Maggini, S., Pierre, A. and Calder, P. C. (2018). Immune Function and Micronutrient Requirements Change over the Life Course. Nutrients,10(10).https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6212925/

3. Huang, Z., Liu, Y., Qi, G., Brand, D. and Zheng, S. G. (2018). Role of Vitamin A in the Immune System. Journal of clinical medicine, Vol.7(9)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6162863/

   3. Ibrahim, K.S. and El-Sayed, E.M.(2016). Potential role of nutrients on immunity. International Food Research Journal, Vol.23(2) http://www.ifrj.upm.edu.my/23%20(02)%202016/(3).pdf