CORONAVIRUS

Can a Supplement Protect Me Against the New Coronavirus?

Doctors say there’s limited evidence on how any supplements may or may not affect coronavirus spread and the resulting disease. Here’s what we know right now.

Last Updated: March 18, 2020

We don't know if taking vitamins or supplements will help your immune system fight off the new coronavirus or affect the severity of your symptoms if you contract it. But experts say some supplements may affect symptom severity when it comes to other viral infections.iStock(2)

Doctors and scientists still have many unanswered questions about the new coronavirus and how it affects our bodies once we are exposed. Washing hands frequently and social distancing are recommended to stop the spread of the virus. But many are asking, is there anything we can do to bolster our immune system’s defense to fight off the virus if we come in contact? Are there supplements that might help?

Again, when it comes to the new coronavirus, there’s no data right now to answer definitely how one supplement might help the immune system fight off the virus or not. But what microbiologists who do study the immune system know about our body’s defense is that ramping up our immune system to be on “high alert” or globally boosting it to fight off every and any germ that might be out there is actually a flawed concept, explains Michael N. Starnbach, PhD, a professor of microbiology at Harvard Medical School in Boston.

Our immune system is designed to recognize things that are foreign in our body and clear those foreign things out of our body, but those cells and responses are finely tuned, says Dr. Starnbach. “If the immune system were too active, it would attack our own tissues, which can happen in some autoimmune diseases, such as rheumatoid arthritis and Crohn’s disease,” he says.

There’s really only evidence that supplements improve immune function in populations that are truly malnourished, which is rarely the case in the United States, according to Starnbach. “People can be more susceptible to diseases when they are severely malnourished, but it doesn’t mean that replenishing higher-than-necessary amounts of vitamins and nutrients in someone is going to make their immune system work that much better," he says.

Evidence suggests some vitamins and supplements may reduce the likelihood of a respiratory virus or reduce the amount of time a person is sick with a virus, especially if a person is deficient in some way, according to Tod Cooperman, MD, the president and founder of Consumer.Lab.com, a provider of independent test results and information designed to help consumers and healthcare professionals identify the best-quality health and nutrition products. Again, we don’t know  whether the vitamins and supplements we have evidence for would yield the same effects against the novel coronavirus.

“Right now, if you’re concerned about catching the coronavirus or any other virus, taking a basic multivitamin every day is a safe way to ensure you’re not deficient in any area,” says Dr. Cooperman. “Eating well, getting good sleep, and exercising will also help keep you as healthy as possible and keep your immune system strong,” he says.

Based on research on the effects of zinc against other viruses, there’s some suggestion it may help lessen severity of symptoms, so if you start to experience symptoms of a virus, including the new coronavirus, Cooperman suggests sucking on zinc lozenges to coat your throat. But right now, there’s no evidence to back that up.

Here’s more about what is known about specific vitamins and supplements that may affect viral infections.

So, What Do We Know About Supplements?

Again the available evidence suggests certain supplements may help when it comes to reducing infection or the duration of illness, says Yufang Lin, MD, an integrative medicine doctor at Cleveland Clinic in Ohio. But little evidence suggests supplements actually help protect you against catching a pathogen in the first place. And there's no evidence that any supplement is a silver bullet that’s going to globally boost your immune response to any and all threats.

And remember, the novel coronavirus is an entirely new threat. There isn’t any specific data yet on how particular vitamins or supplements may or may not thwart it, says Dr. Lin. (All the studies referenced below investigate how supplements work against other types of viruses.) “We really don’t know if they would provide support in fighting off COVID-19 [the disease spread by the novel coronavirus],” she says.

Here’s what we do know.

Elderberry There’s data that suggests elderberry (taken in teas, lozenges, gummies, or pills with the herb) can reduce flu virus production and help people recover from flu faster, Lin says. A study published in March 2019 in the Journal of Functional Foods found that compounds from elderberries can inhibit the virus’s entry and replication in human cells and help strengthen a person’s immune response to the virus. There is no really good data for the common cold and elderberry, Lin adds.

RELATED: Cold and Flu: Everything You Need to Know

Zinc does have some data suggesting it can provide support for your immune system and may help you fight off infection in common colds faster, Lin says. A meta-analysis published in the journal JRSM Open in May 2017 found evidence that zinc lozenges can shorten the common cold's duration by over 30 percent. The findings recommended that the lozenges not contain citric acid or salt citrate. “[It’s an approach] that you can think about taking within the first few days of infection,” she adds.

Remember, zinc has not been tested specifically with the new coronavirus, but it has been tested with other viruses, he says. When it comes to other viruses, zinc lozenges work by inhibiting the viruses' activity in the throat, when the infection is just starting to spread, lessening those symptoms. So taking those lozenges soon after you begin experiencing symptoms may help, Cooperman explains. “It’s fairly safe for a week or two. You want to suck on the lozenges, but not chew, so your throat is continually coated with zinc,” he says.

Make sure you follow the instructions on the package and that you’re not taking more than the recommended dose, Cooperman adds. 

Vitamin C is associated with some benefits for colds, Lin notes. (The common cold is a type of coronavirus.) A meta-analysis of 29 trials including 11,306 people looked at how taking at least 200 milligrams (mg) per day of vitamin C affected risk and management of colds. The study, published in Cochrane Database of Systematic Reviews, found that vitamin C didn’t reduce the incidence of colds in adults, but it did shorten the duration of colds, by 8 percent. A subgroup of studies in the Cochrane analysis looked at marathon runners, skiers and Army troops doing heavy exercise in very cold conditions and found that supplements of at least 200 mg of vitamin C every day appeared to cut the risk of getting a cold by 50 percent.

Lin recommends aiming to get the vitamin C you do need daily and focus on getting it from food sources, rather than supplements. “I would encourage eating vitamin C–rich vegetables to boost your levels of vitamin C,” she says. The recommended daily amount of vitamin C for adults is 75 to 90 milligrams (mg) a day, according to the National Institutes of Health. One orange contains about 75 mg, a green pepper contains about 60 mg, and a half cup of Brussels sprouts has almost 50 mg.

Taking very large doses of vitamin C isn’t recommended; once doses go above 400 mg, vitamin C is just excreted in the urine, according to the Harvard Health Letter. 

Vitamin D is important for maintaining a strong immune system, according to Cooperman. And low levels of vitamin D are associated with frequent colds and influenza, according to the National Institutes of Health. Because we get a lot of the vitamin D we need from sunshine, many people see their levels drop off during the winter months, says Cooperman. It’s not necessary to have your levels checked to safely take vitamin D; Cooperman recommends 600 to 800 IU or 15 to 20 micrograms if you decide to take supplements.

A meta-analysis of prospective trials published in the journal BMJ in 2017 found that vitamin D reduced the odds of developing a respiratory infection by 42 percent in people who were vitamin D deficient. Note: Dosage matters. Taking a daily dose of D3 between 300 IU and 4,000 IU was more effective than taking a large monthly dose, according to the BMJ report.

In a randomized, double-blind placebo trial of 5,110 older adults who were vitamin D deficient (published in August 2019 in the journal Clinical Infectious Diseases), the data again showed that large doses may not be beneficial in preventing respiratory infection. Participants were given 200,000 IU at the start of the study followed by 100,000 IU monthly, with a mean follow-up of 1.6 years. Investigators found no reduction in the number of acute respiratory infections compared with placebo.

If you’re not deficient, vitamin D won’t really provide a lot of additional benefit, but if you are deficient, taking the supplement can strengthen immunity, says Cooperman.

Apple cider vinegar Though apple cider vinegar (ACV) does boast some other health benefits, there isn’t evidence to show that ACV affects immune function or that taking it regularly improves your chances of fighting off viruses, Lin says.

Turmeric While there is some evidence turmeric may yield some health benefits, including helping manage high cholesterol, glucose control, and digestive issues, there isn’t specific evidence that it can help fight off a virus, says Lin. There is, however, evidence suggesting one of the active compounds in turmeric (curcumin) does act on immune function in some way, though how those effects may or may not benefit health is still unclear, according to a review published in the Journal of Clinical Immunology.

As always, let your doctor know about all supplements you are taking or plan to take, as they can pose unintended health risks for certain groups or interact with other medications you're taking.