As COVID-19 continues to spread, you may wonder what you can do besides the well-known behavior changes (frequent handwashing, social distancing, etc.) to protect yourself from illness. An additional important strategy to remain healthy is to support your immune system with the right nutrients.

Significant research shows that certain vitamins, minerals, and essential fatty acids play important roles in immunity. These nutrients support the specialized defenses that keep viruses and bacteria out of our bodies, destroy invaders that enter, and assist with recovery from illness and infection.

Nutrients for the Immune System

Many nutrients form the foundation of a healthy immune system. If you fall short of any of these nutrients highlighted here, you have more risk for serious illness and infection.

Do your usual food choices meet our recommendations on this list? Contact a registered dietitian nutritionist (RDN) to see how your daily diet measures up.

If you think you are falling short, be sure to check the “Where can I get more?” section of the table. We list a few food examples to help you get started, but the LPI has nutrition information for many additional foods at its Micronutrient Information Center.

If you already know that your body is low in a specific nutrient, such as iron in the case of anemia, focus on that nutrient first. 

If you have anemia...

Anemia weakens the immune system. Low folate, vitamin B6, vitamin B12, or iron can all be possible causes. If you have anemia, work with your doctor to determine which nutrients might help you resolve it as soon as possible.

Nutrient

The LPI
Recommendation

Where can I get more?

DHA
(an omega-3 fatty acid)

Men & Women: Eat two servings of oily fish every week

1 large egg 30 mg
3 oz salmon 500-1,200 mg
fish or algae oil supplements

Vitamin A
(including beta-carotene)

Men: 900 µg/day
Women: 700 µg/day

1 large egg 80 µg
½ cup raw carrot 500 µg
½ cup baked sweet potato 900 µg

Vitamin C

Men & Women: 400 mg/day

1 cup bell pepper 120-190 mg
1 kiwifruit 70-90 mg
1 cup strawberries 80-100 mg

Vitamin D

Men & Women: 2,000 IU/day

3 oz salmon 300-500 IU
fortified milk 80-120 IU
fortified cereal varies
sunshine

Vitamin E

Men & Women: 15 mg/day

½ cup almonds 10-12 mg
¼ cup sunflower oil 25 mg
1 cup avocado 3 mg

Folate or Folic Acid

Men & Women: 400 µg/day

1 cup cooked lentils 180 µg
1 cup cooked spinach 130 µg
1 slide enriched bread  20-50 µg

Vitamin B12

Men & Women: 2.4 µg/day

3 oz beef 3-6 µg
1 cup milk  1 µg
fortified cereals  varies

Vitamin B6

Men & Women: 1.3 mg/day

3 oz chicken 0.5 mg
1 cup canned chickpeas 1.1 mg
1 banana 0.4 mg

Zinc

Men: 11 mg/day
Women: 8 mg/day

3 oz beef 4-9 mg
1 oz cashews 1.6 mg
1 cup yogurt 1.7 mg

Iron

Men: 8 mg/day
Women: 18 mg/day

Before menopause women need 18 mg of iron per day. After menopause, this requirement goes down to 8 mg/day

3 oz beef 1.5-2.5 mg
1 oz pumpkin seeds  0.9 mg
1 cup cooked lentils 6.6 mg

Copper

Men & Women: 900 µg/day

1 oz dark chocolate 500 µg
1 oz cashews 625 µg
½ shitake mushrooms 650 µg

Selenium

Men & Women: 55 µg/day

3 oz tuna 90 µg
1 cup cottage cheese 20 µg
1 slice whole-wheat bread 13 µg

These recommendations are for all adults under 50 who are not pregnant or breastfeeding.

Adults over 50 may need additional vitamin B6 and vitamin B12 from supplements, and no supplemental iron. See our recommendations for older adults for more information.

Amounts of nutrients listed are approximate and can depend on source and preparation.

All of the LPI recommendations meet or exceed the recommendations of the National Academy of Medicine.

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Can Supplements Help?

While it is best to get most of your nutrients from foods, it is not always possible. The best strategy is to know where you fall short and add supplements to fill the gaps. The experts at the Linus Pauling Institute have identified four “immune essential” supplements that all adults should consider taking.

Vitamin C, vitamin D, DHA (an omega-3 fatty acid), and zinc all can help our bodies fight off infection. Following our guidelines, you can add one or more of these supplements to help support your immune system.

Multivitamins are also important to reach your goals. These supplements can help you reach all of the LPI recommendations, especially for minerals.

Most general multivitamins will provide what you need. An expensive brand is not necessarily better.

Important: be sure to select the right type for you, such as those for women or older adults.

Multivitamin tips:
  • Your multivitamin should contain 100% of the Daily Value (or close to it) for all of the vitamins and minerals listed in the table above.
  • Look for quality testing on your supplements, like the USP or NSF seal.
  • Check if your multivitamin has zinc. Make sure not to exceed 40 mg of zinc per day from food and supplements combined.
What about Older Adults?

As we get older, our immune system does not function as well as it used to. This is related to not absorbing nutrients from foods as well as younger adults and also needing more nutrients as we age. For these reasons, it is important for older adults to take certain supplements.

Therefore, the LPI has set specific supplement recommendations for older adults. All of the guidelines listed here will help people over the age of 50 support their immune system.

Caution: Older adults should not get too much iron (8 mg/day from food is enough) or zinc (no more than 40 mg/day).

LPI Recommendations
for Adults Over 50

In addition to the above, look for the following in your multivitamin supplement:

  • 2 mg vitamin B6
  • At least 100 µg of vitamin B12
  • 10-15 mg of zinc
  • No iron

Also, make sure you are getting:

  • 2,000 IU/day or more from vitamin D from supplements
  • 400 mg/day or more of vitamin C from all sources
Conclusions

Optimal nutrition promotes optimal immune function. To fight viruses and support a strong immune system, it is very important to get the nutrients you need to stay healthy.

In times of health crisis, we would all do well to follow these general guidelines: eat a balanced diet and take a daily multivitamin. For extra support, consider taking “immune essential” supplements, especially older adults.

Authors: Alexander Michels, PhD; Victoria Drake, PhD; Sandra Uesugi, RN, BSN, MS; Carmen Wong, PhD; Emily Ho, PhD; and Adrian Gombart, PhD, all from the Linus Pauling Institute at Oregon State University. Contact information here.