A nutritious diet is a cornerstone of healthy living and disease prevention. And this is equally important during this pandemic. Food gives us essential nutrients for the building blocks of our body, including our immune system. This connection has led to questions about the role supplements might have. But do supplements prevent COVID-19?

Supplements consist of vitamins and minerals sold, usually in pill form, for the purposes of improving health. It’s a multi-billion dollar industry and growing each year. The industry is largely based on the premise that if a nutrient is good for you, then more is better.

grocery shopping for supplements

More People Buying Supplements

Recent months have seen a surge in people buying supplements in hopes to ward off COVID-19. And it’s not just the wellness industry jumping on the pandemic bandwagon. Athletes and celebrities such as Tom Brady are taking advantage of the pandemic to promote their products.

It’s understandable why we might turn to supplements in the face of a health crisis with no cure. This is a period of uncertainty and anxiety, and using supplements may be one way to exert control over the situation. However, there is limited evidence of the effects of supplementation on the immune system and the prevention of infections.

While some say there is no harm in taking supplements to prevent COVID-19, this may not be the case. The potential harms include not taking other measures seriously such as hand washing and physical distancing. And one can also overdose on supplements.

Some of the nutrients that have gained attention recently include vitamins C and D, along with zinc. All three of these are involved in the immune system in some way. And all have some limited scientific evidence behind them with regards to other viruses and infections. However, what may work against one particular virus, does not mean it will prevent COVID-19.


Vitamin C

Vitamin C is water-soluble antioxidant that helps remove damaged cells. In lab studies, vitamin C increases the production and function of some immune cells. It gained popularity when Linus Pauling started ingesting mega-doses as a ‘cure’ for the common cold. However, this cure has never been realized. At most, regular vitamin C may shorten the duration of a cold, but only by about 8%, or about 10 hours over a five-day cold.

Since your body does not produce, or store vitamin C, it’s important to include in your diet. The recommended intake is between 75 mg to 90 mg per day. This is the amount in a large orange, one cup of broccoli or a small red pepper. While excess amounts are generally excreted in the urine, mega-doses may result in intestinal discomfort.

There has been some interest about vitamin C as studies have suggested a benefit in people suffering from sepsis. Sepsis is the body’s extreme reaction to an infection that can lead to organ damage and death if untreated. In these studies, vitamin C is delivered intravenously in doses around fifty times that of dietary recommendations. But not all studies are in agreement. With respect to COVID-19, research is currently underway in patients with severe and critical cases.


Vitamin D

Vitamin D is a building block for bones and many steroids in the body. There’s been excitement regarding the role vitamin D may have in preventing and treating COVID-19. Earlier studies have indicated vitamin D may protect against respiratory infections. And the effect tends to be greatest in those with vitamin D deficiency.

Low levels of vitamin D are more common in people with darker skin and higher amounts of body fat. And early data suggest that hospitalizations and deaths from COVID-19 are greater in these two populations. This connection has led to scientists to study mega-doses of vitamin D in people with moderate and severe symptoms.

The main source of vitamin D is from the sun. However, with concerns of skin cancer taking priority over vitamin D deficiency, food has become a main source. One cup of fortified milk provides approximately 20% of the daily recommended 600 IU intake. Having too much vitamin D is unlikely through natural sources. But taking mega-doses through supplements can result in toxic effects to the body.

Supplementation is commonly recommended during the winter months and in people with darker skin living away from the equator. Recently, Public Health England has recommended adults take 10 micrograms daily as a result of staying indoors during lockdown.



Zinc is a nutrient required for a number of the body’s functions. For the immune system, zinc helps fight off infections and keeps the immune response from getting out of control (possibly preventing sepsis). Zinc may also reduce severity and duration of the common cold. People who took zinc lozenges (twice daily recommended amount) reduced the duration of their colds by 40%.

It’s not clear how zinc works with respect to the common cold. It may prevent the virus from replicating in the body. However, it’s unknown whether zinc has any effect on the COVID-19 virus. That being said, a number of studies are currently underway.

The daily recommended zinc intake is between 8 to 11 mg. This is easily obtained through food. Oysters are rich in zinc but most people get sufficient amounts from meat, dairy products, beans and peas.

will supplements prevent covid-19

When should you take supplements?

In societies where healthy food is readily available, nutrient deficiencies are rare. However, in older adults and medical conditions which result in diminished appetite, a supplement may be warranted. Before you start, talk to your doctor first as some supplements interfere with prescribed medications.

While some supplements have shown benefit in reducing duration of viruses such as the common cold, how this applies to preventing COVD-19 is unknown. The current studies underway should shed light on the role of supplements in treating COVID-19 but it may take time for these results to be known. In the meantime, a balanced diet, regular activity, frequent hand washing and physical distancing remain the best strategies for reducing your chances of getting COVID-19.

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