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Your immune system is complicated. There are many specialized cells that protect your body from infections, disease, pathogens, and also heal the body when tissues are damaged. There are many ways that you can help your immune system work at its highest potential, but we are going to talk about a few vitamins and minerals that are essential.

Vitamin D, Vitamin A, Zinc and Selenium have been shown to play important roles in the immune system.  There is lots of research showing that a deficiency of these puts people at a higher risk for developing disease and have compromised immune systems. There are biochemical pathways that these play an essential role in regulating immune cells, and inflammatory pathways.  I’ve attached references to articles that are free on the internet that give summaries how each function in the immune system at the end of the article. If you have normal levels of nutrition, there is lacking evidence whether or not extra will help, but all of these supplements have high toxicity levels, so it shouldn’t hurt to try.

Try to make sure that you are getting enough variation in your diet to get the right amount of vitamins and minerals. Typically food sources are the preferred choice to get your nutrients. Yet if you have restrictions to your diet, supplementation can help as well. So here is a summary of the four vitamins that make your immune system function its best! 

Vitamin D

• Other names: ergocalciferol (D2), cholecalciferol (D3)
• Food Sources: Fish (tuna, salmon, mackerel), eggs, fortified foods (milk and other dairy product)
• Other sources: Exposure to the sun
• Recommended Daily Amount (if normal blood levels): 600 IU for adults under 70 years old
• Upper limit (possible toxic effects): 4000 IU for 9+ years old
• Immune System: receptors on immune cells help modulate innate and adaptive immune responses

Vitamin A

• Other names: retinol, retinal, and retinyl esters, beta-carotene
• Food Sources: Spinach, sweet potatoes, pumpkin, carrots, fish, eggs
• Recommended Daily Amount: 900 mcg RAE Adult males, 700 mcg RAE Adult females (mcg RAE is a new unit which stands for retinol  activity equivalents, and takes into consideration the source of the vitamin A)
• Upper Limit (possible toxic effects): 3000 mcg 19+ years old
• Immune System: Cell growth and differentiation

Zinc

• Food Sources: Oysters, red meat, poultry, fortified cereals
• Recommended Daily Amount: 11 mg males, 8 mg females 19+ years old
• Upper Limit (possible toxic effects): 40 mg 19+ years old
• Immune System: intracellular communication for innate and adaptive immunity

Selenium

• Other names: selenate, selenite, selenomethionine and selenocysteine
• Food Sources: Brazil nuts, seafood, ham
• Recommended Daily Amount: 50 mcg 19+ years old
• Upper Limit (possible toxic effects): 400 mcg
• Immune System: enhanced immune cell proliferation

Disclaimers: Always consult your doctor if you have clinically low levels of vitamins or minerals. There is no research to suggest that these nutrients will decrease your chances of getting, recovering, or decreasing severity of COVID-19 infections.

There is great information if you look at the National Institute of Health’s  Office of Dietary Supplements https://ods.od.nih.gov/

Scientific References

Vitamin D

Medrano M, Carrillo-Cruz E, Montero I, Perez-Simon JA. Vitamin D: Effect on Haematopoiesis and Immune System and Clinical Applications. Int J Mol Sci. 2018;19(9):2663. Published 2018 Sep 8. doi:10.3390/ijms19092663

Vitamin A

Stephensen CB. Vitamin A, infection, and immune function. Annu Rev Nutr. 2001;21:167–192. doi:10.1146/annurev.nutr.21.1.167

Oliveira LM, Teixeira FME, Sato MN. Impact of Retinoic Acid on Immune Cells and Inflammatory Diseases. Mediators Inflamm. 2018;2018:3067126. Published 2018 Aug 9. doi:10.1155/2018/3067126

Zinc

Wessels I, Maywald M, Rink L. Zinc as a Gatekeeper of Immune Function. Nutrients. 2017;9(12):1286. Published 2017 Nov 25. doi:10.3390/nu9121286

Selenium

Avery JC, Hoffmann PR. Selenium, Selenoproteins, and Immunity. Nutrients. 2018;10(9):1203. Published 2018 Sep 1. doi:10.3390/nu10091203

Prabhu KS, Lei XG. Selenium. Adv Nutr. 2016;7(2):415–417. Published 2016 Mar 15. doi:10.3945/an.115.010785