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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.






David Quimby, MD
David Quimby, MD

David Quimby, MD is an infectious diseases physician at CHI Health.

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