Written by: Yaisli Lorenzo, MS, RDN 

 

Balanced nutrition is essential, especially to reduce the risk of getting sick from COVID-19. A balanced nutrition supplies crucial building blocks to the immune system called vitamins and minerals.1 There is a vital connection between eating behaviors and the immune system.2 

 

There are two types of immune systems. The first defense line is innate immunity. When the body detects pathogens, the innate system responds first to the threat. It tries to keep pathogens from traveling the body. Pathogens are bacteria, viruses, parasites, or other foreign materials. The second line of defense is the adaptive system. This system develops as we grow and are exposed to things. Adaptive immunity remembers what it previously did to defend the body when fighting the same pathogen.3 

 

Not eating enough vitamins and minerals increases your risk of getting sick.4 White blood cells, like leukocytes, are the body’s fighter cells. Leukocytes require vitamin C to function properly. Therefore, vitamin C can help fight infections.5 Vitamin C sources are peppers, citrus fruits, kiwi, broccoli, strawberries, and brussels sprouts.6 A vitamin C supplement of 1000 mg twice a day is recommended during the pandemic.7 A helpful tip when taking vitamin C is to split the amount throughout the day. Eating high doses in one serving will reduce the amount the body absorbs.6 

 

Macrophages and T cells are other types of leukocytes. Macrophages are part of the innate system, while T cells are from the adaptive system.8 Both require vitamin D to function.9 Vitamin D sources are cod liver oil, fatty fishes (trout and salmon), mushrooms, fortified beverages, and cereals.10 To see if a food has vitamin D, look at the food label. A vitamin D3 supplement of 1000 IU twice a day is recommended during the pandemic.7 Vitamin D is best absorbed with oils so consume supplements with meals.10 

 

Zinc is vital in the function of innate cells, like neutrophils and natural killer cells. Low levels of zinc in the body prevents our immune system from creating strong responses and, therefore, will not fight off infections quickly.11 Zinc sources are shellfish, meats, poultry, legumes (chickpeas and lentils), and seeds (pumpkin seeds and sesame seeds).12 A zinc supplement of 40 mg or less daily is recommended during the pandemic.7 

 

Other nutrients boost immune system function. Vitamin A can help during the recovery from getting sick.13 Vitamin A sources are egg yolks, liver, butter, cod liver oil, salmon, orange vegetables, and leafy greens. Eat vitamin A sources with a meal improves absorption.14 Niacin, also known as vitamin B3, can reduce inflammation and damage to the lungs.15 Niacin sources are poultry, fish, beef, nutritional yeast, peanuts, and lentils.16  

 

 

 

 

Vitamin B9 is also known as folate and folic acid. Folate is found in unprocessed foods, while folic acid is in fortified foods.17 Having adequate vitamin B9 can protect you from respiratory infections.18 Folate sources are leafy greens, broccoli, avocado, citrus fruits, eggs, and liver. Folic acid sources are ready-to-eat cereals, bread, and tortillas.17 Probiotics can balance the levels of good bacteria’s in the gut. A substantial part of your immune system reflects the health of your gut.19 Probiotics sources are fermented drinks and foods. Fermented beverages include yogurts, kefir, and milk drinks. Fermented foods are pickled vegetables, tempeh, miso, kimchi, and sauerkraut.20 

 

References: 

 

  1. Adrian F. Gombart, Adeline Pierre, Silvia Maggini. A Review of Micronutrients and the Immune System–Working in Harmony to Reduce the Risk of Infection. Nutrients. 2020;12(1):236. doi:10.3390/nu12010236 
  2. Butler MJ, Barrientos RM. The impact of nutrition on COVID-19 susceptibility and long-term consequences. Brain Behavior and Immunity. 2020;87:53-54. doi:10.1016/j.bbi.2020.04.040 
  3. InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. The innate and adaptive immune systems. [Updated 2020 Jul 30]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279396/ 
  4. Childs CE, Calder PC, Miles EA. Diet and Immune Function. Nutrients. 2019;11(8). doi:10.3390/nu11081933 
  5. Carr AC, Maggini S. Vitamin C and Immune Function. Nutrients. 2017;9(11):1211. Published 2017 Nov 3. doi:10.3390/nu9111211 
  6. Fact Sheet for Health Professionals: Vitamin C. Office of Dietary Supplements at National Institutes of Health: Strengthening Knowledge and Understanding of Dietary Supplements. Updated February 27, 2020. 
  7. de Faria Coelho-Ravagnani C, Corgosinho FC, Sanches FFZ, Prado CMM, Laviano A, Mota JF. Dietary recommendations during the COVID-19 pandemic [published online ahead of print, 2020 Jul 12]. Nutr Rev. 2020;nuaa067. doi:10.1093/nutrit/nuaa067 
  8. Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Helper T Cells and Lymphocyte Activation. Available from: https://www.ncbi.nlm.nih.gov/books/NBK26827/ 
  9. Di Rosa M, Malaguarnera M, Nicoletti F, Malaguarnera L. Vitamin D3: a helpful immuno-modulator. Immunology. 2011;134(2):123-139. doi:10.1111/j.1365-2567.2011.03482.x 
  10. Fact Sheet for Health Professionals: Vitamin D. Office of Dietary Supplements at National Institutes of Health: Strengthening Knowledge and Understanding of Dietary Supplements. Updated October 9, 2020. 
  11. Maywald M, Wessels I, Rink L. Zinc Signals and Immunity. Int J Mol Sci. 2017;18(10):2222. Published 2017 Oct 24. doi:10.3390/ijms18102222 
  12. Fact Sheet for Health Professionals: Zinc. Office of Dietary Supplements at National Institutes of Health: Strengthening Knowledge and Understanding of Dietary Supplements. Updated July 15, 2020. 
  13. Imdad A, Mayo-Wilson E, Herzer K, Bhutta ZA. Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age. The Cochrane database of systematic reviews. 2017;3:CD008524. doi:10.1002/14651858.CD008524.pub3 
  14. Fact Sheet for Health Professionals: Vitamin A. Office of Dietary Supplements at National Institutes of Health: Strengthening Knowledge and Understanding of Dietary Supplements. Updated February 14, 2020. 
  15. Fact Sheet for Health Professionals: Zinc. Office of Dietary Supplements at National Institutes of Health: Strengthening Knowledge and Understanding of Dietary Supplements. Updated July 15, 2020. 
  16. Fact Sheet for Health Professionals: Niacin. Office of Dietary Supplements at National Institutes of Health: Strengthening Knowledge and Understanding of Dietary Supplements. Updated June 3, 2020. 
  17. Fact Sheet for Health Professionals: Folate. Office of Dietary Supplements at National Institutes of Health: Strengthening Knowledge and Understanding of Dietary Supplements. Updated June 3, 2020. 
  18. Alfonso VH, Bandoli G, von Ehrenstein O, Ritz B. Early Folic Acid Supplement Initiation and Risk of Adverse Early Childhood Respiratory Health: A Population-based Study. Maternal and Child Health Journal. 2018;(1):111. doi:10.1007/s10995-017-2360-6 
  19. Desh D. Singh, Sarika Amdeka, Vinod Singh. Probiotics: defenders of gastrointestinal habitats. Gastroenterology Insights. 2012;4(2):e22. doi:10.4081/gi.2012.e22 
  20. Fact Sheet for Health Professionals: Probiotics. Office of Dietary Supplements at National Institutes of Health: Strengthening Knowledge and Understanding of Dietary Supplements. Updated June 3, 2020.