Coronavirus Nutrition Wellness

Can Vitamins Fight COVID-19? Expert Advice on Supplement Use

August 20, 2020

Can Vitamins Fight COVID-19? Expert Advice on Supplement Use

We all want to protect ourselves, and our families, from the Coronavirus. Could adding vitamins to your morning routine give you an edge?

Studies are ongoing but there is no clear information regarding how vitamins and minerals impact COVID-19. We simply can’t – as of yet – say with any certainty whether they offer any benefit.

We do know that supplements can interfere with other medicines you are prescribed. Taking zinc, for example, can decrease the effectiveness of an antibiotic. Taking too much of any vitamin can result in toxicity. That’s why it’s important to talk to your care provider before adding supplements to your regimen.

What can you do? It’s never bad advice to eat healthy and get regular moderate exercise. Here’s what we can say about some common vitamins:

Vitamin D

Vitamin D is important for strong bones, and it also plays a role in our natural immune system, so it’s best to not be vitamin D deficient. Unfortunately, many people don’t get enough vitamin D. Nearly 42% of participants were found to be vitamin D deficient in data collected by the National Health and Nutrition Examination survey (NHANE).1

You typically get vitamin D from sunshine, fatty fish and seafood, mushrooms, egg yolks and vitamin D-fortified foods (milk, orange juice, cereal, yogurt, tofu). How much you need depends on your age and other factors. The only way to know whether you need more is to get your vitamin D level tested by your care provider.

You can take too much vitamin D – and excess amounts can even damage the kidneys. Signs of toxicity include nausea, vomiting, poor appetite, constipation, weakness and weight loss.2


Zinc has various benefits, including some known anti-viral effects. It plays a part in how the immune system fights bacteria and viruses, helps the body heal wounds and even has a role in your senses of taste and smell.

Most people get enough zinc from the foods they eat, such as red meat and poultry. Oysters contain the most zinc per serving. Other sources include whole grains, beans, nuts, fortified cereals, dairy products and crab and lobster.

Zinc deficiency is rare, but you can get too much zinc – and too much for a long time can even cause lower immunity. Signs of toxicity include nausea, vomiting, appetite loss, stomach cramps, diarrhea and headaches.3

Vitamin C

Vitamin C has been touted as beneficial for infection prevention and fighting acute infections. Large randomized trials of vitamin C in sepsis have had somewhat contradictory results. There are studies ongoing with vitamin C and COVID-19 but results are not yet in.

We do know that vitamin C helps protect the body’s cells from damage, plays a role the body’s production of collagen, a protein needed for wound healing, improves the absorption of iron from plant-based foods and assists the immune system.

We get vitamin C from fruits and vegetables, including citrus fruits, red and green peppers, broccoli, strawberries, baked potatoes and tomatoes. Vitamin C deficiency is rare in the U.S., and too much can cause diarrhea, nausea, stomach cramps and body tissue damage for people with a condition called hemochromatosis.4

When it comes to supplements, buyer beware is the best advice – especially when supplement makers tout impressive results. When in doubt, talk to your care provider. We will always put your health and safety first.






  1. Lovely

    Thanks for this information it helps a lot.

  2. CHI Health

    This vitamin can be pretty hard to overdose on, because it is water-soluble. So excess vitamin C is removed via the urine. There are some centers that actually give patients mega-doses of vitamin C through the vein. However, this is not how most people get their supplements (most take a pill). I will often recommend vitamin C supplementation to patients with recurrent urinary tract infections as a preventative, not for any immune-related reasons, but just because it is excreted in the urine and changes the acidity of the urine. For these patients, "the more the merrier" is generally what I tell them; to increase dose until they have stomach upset (nausea and cramping), and then go to the dose lower than this. Most people can tolerate 500mg three times a day (total of 1500mg/day) in vitamin C supplements without stomach issues. But really, excessive amounts of vitamin C just tends to give you a lot of vitamin C in your urine, not necessarily any health benefits. -Dr. Quimby

  3. CHI Health

    For general health purposes, you want to make sure you have at least 11-15mg of elemental zinc every day. Supplements have much more than this, but the total mg in the supplement is NOT the amount of zinc in it. For example, if the supplement is Zinc Sulfate, only 23% of the total dose is elemental zinc, so a 220mg supplement dose has 50mg of elemental zinc. Other formulations (zinc gluconate, for example) are different percentages. As long as you're not going above averaging 150mg of elemental zinc/day, shouldn't have much in the way of health effects. Over 150mg of elemental zinc per day may end up making you deficient in copper, alter iron metabolism, cause immune issues, etc. Too much zinc can also cause stomach upset, but it should be pretty obvious if you have that.

  4. Penny

    I take all three of these also , they don't tell you how much we should have or how much is too much. I have been splitting my zinc.

  5. Tomas

    That's very comfy to have only 3 very common and not expensive supplements to save you and your family health in such a hard time. Thanks!

  6. Rick Fiscus

    Thank you for this info. I have been taking zinc everyday, should I take every other day?

  7. David Bell

    The article states that “taking too much of any vitamin can cause toxicity.” I appreciate that guidance but would appreciate a bit more detail. For example, what constitutes too much vitamin C? Specifically, is it possible to take so much vitamin C that it would result is some sort of clinical toxicity?

  8. Elizabeth

    I take vitamin C and vitamin D and zinc every day. These are my preventative methods. Extra vitamin D in the winter because we don’t have as much sunshine

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