Flu season is upon us, so we need to strengthen our immune system.   The best way to keep your immune system healthy is to eat the correct foods!  We must understand that we get the best vitamins and minerals for our body  from the food we eat. When we increase immune building foods we improve our body’s chance of fighting off  viruses and other pathogens that make us sick.

Here is a list of vitamins, minerals and foods that especially help our immune system:

Vitamin D is a fat-soluble vitamin that is essential for the body’s absorption of calcium and phosphorus and promotes bone health. It also plays a role in immune and muscle function. Vitamin D deficiency is associated with increased susceptibility to infection. The risk of infection is highest in the winter months as sunlight is the most abundant source of vitamin D, and we get less in the winter. Exposure to sunlight has shown to reduce the risk of death from many causes, however, we must remember to use UV A and B sun protection. Rates of vitamin D deficiency in both men and women are increasing, mostly in elderly individuals and people with chronic health conditions. 

Foods to include on your shopping list to help boost your vitamin D levels:

International Units (IU) Source Serving size
447 Salmon (sockeye, cooked) 3 oz
154 Tuna (canned in water, drained) 3 oz
~120 Milk (fortified) 1 cup
80 Yogurt (fortified) 6 oz
46 Sardines (canned in oil) 2
42 Beef liver (cooked) 3 oz
41 Egg yolk 1, large
6 Swiss cheese 1 oz

Recommended daily amount (RDA) for most adults is 600-800 IU

Zinc deficiency is one of the most prevalent nutrient deficiencies globally. Sufficient levels of zinc are crucial for normal development and the function of immune cells, DNA synthesis, and wound healing.  Zinc deficiency increases the incidence and duration of infections,  mental disturbances and can interfere with normal growth and development during pregnancy and childhood.

Food products that supply the body with zinc are below:

Milligrams (mg) Source Serving size
74 Oysters 3 oz
6.5 Crab (Alaska King) 3 oz
3.4 Lobster (cooked) 3 oz
2.9 Baked beans ½ cup
2.2 Pumpkin seeds (dried) 1 oz
1.6 Cashews 1 oz
1.3 Chickpeas (cooked) ½ cup
0.9 Cheese (cheddar or mozzarella) 1 oz

RDA for adults is 8 mg for women and 11 mg for men

Vitamin C is a water-soluble vitamin that humans are unable to produce on their own, making it essential to receive in our diet. Vitamin C is a key player in our immune defense mechanisms. It supports membrane function of our skin and mucous membranes, enhances wound healing, and is a potent antioxidant.

Dietary sources for Vitamin C include:

Milligrams (mg) Source Serving size
95 Sweet red pepper (raw) ½ cup
70 Orange 1
60 Sweet green pepper (raw) ½ cup
49 Strawberries (fresh) ½ cup
48 Brussel sprouts (cooked) ½ cup
29 Cantaloupe ½ cup
17 Potato (baked) 1, medium
8 Green peas ½ cup

RDA for adults is 75 mg for women and 90 mg for men

Vitamin A is known as the “anti-inflammation vitamin”. It helps to promote and regulate both our innate and adaptive immune system and has an essential role in the formation of our epithelial membranes which is our first line of immune defense. It also has a role in maintenance of healthy vision and growth. The following are some grocery items to help you achieve adequate levels of this essential nutrient:

Micrograms (mcg) Source Serving size
1,403 Sweet potato (baked in skin) 1
459 Carrots (raw) ½ cup
135 Cantaloupe ½ cup
117 Sweet red pepper (raw) ½ cup
75 Egg (hard boiled) 1 large
59 Salmon (sockeye, cooked) 3 oz
32 Yogurt (plain, low fat) 1 cup
10 Summer squash (boiled) ½ cup

RDA for adults is 700 mcg for women and 900 mcg for men

Selenium is known as an ultra-trace element with many biological functions. It plays a major role in immunoregulation, helping the immune system to mount proper responses and preventing it from over-responding.  We can only receive selenium by obtaining it through dietary sources.

It is essential to include some of the following foods in our diet:

Micrograms (mcg) Source Serving size
544 Brazil nuts 1 oz
45 Sardines (canned in oil) 3 oz
42 Ham (roasted) 3 oz
20 Cottage cheese (1% milk fat) 1 cup
19 Brown rice (long grain) 1 cup
15 Egg (hard boiled) 1 large
4 Marinara sauce 1 cup
3 Cashews 1 oz

RDA for most adults is 55 mcg

Spotlight foods provide us with multiple of our essential nutrients.  Bes sure to include these in your diet:

  • Sardines – Vitamin D and Selenium
  • Salmon – Vitamin D and Vitamin A
  • Cashews – Zinc and Selenium
  • Cantaloupe – Vitamins C and A
  • Sweet red pepper – Vitamins C and A
  • Hard boiled egg – Vitamin C and Selenium

References

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  2. Grant, WB et al. Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths. Nutrients. 2020; 12(4): 988. doi.org/10.3390/nu12040988 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7231123/
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  9. “The Nutrition Source – Zinc.” Harvard School of Public Health. Retrieved from https://www.hsph.harvard.edu/nutritionsource/zinc/
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  12. “Vitamin C Fact Sheet for Health Professionals.” National Institute of Health. (27 Feb. 2020). Retrieved from https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/
  13. Huang Z, Liu Y, Qi G, Brand D, Zheng SG. Role of Vitamin A in the Immune System. J Clin Med. 2018;7(9):258. Published 2018 Sep 6. doi:10.3390/jcm7090258 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6162863/
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  16. “Selenium Fact Sheet for Health Professionals.” National Institute of Health. (11 Mar. 2020). Retrieved from https://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/

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