Reading: 8 Ways to Boost Your Immunity in the age of COVID-19

Back in early March, when I actually left the house and went to stores, I found myself scouring the shelves of local pharmacies and supermarkets for zinc lozenges. I had set out on this quest after reading an email by pathologist and coronavirus expert James Robb, MD, suggesting that these lozenges were effective in blocking coronavirus from multiplying in your throat and nasopharynx. The email, meant for Dr. Robb’s family and friends, went viral on social media. Clearly, many others had read the same post: The shelves were empty.

According to The New York Times, sales of so-called immune-boosting supplements skyrocketed in March: Vitamin C was up 146 percent, zinc 255 percent, and elderberry extract a whopping 415 percent. While some of the panic-buying may have been spurred by Dr. Oz’s suggestion on the Today show that such supplements could help boost one’s defenses against COVID-19, some companies have preyed on the public’s fear, causing the Food and Drug Administration (FDA) and the Federal Trade Commission (FTC) to send warning letters to several businesses for selling unapproved products intended to prevent or treat the disease. 

Still, many of us are left wondering if there are supplements we should take — or lifestyle changes we should make — that can help shore up our defenses against COVID-19? 

“It is always important to maintain your immune response,” says Yale University immunologist Akiko Iwasaki, PhD. “Things you can do include getting enough sleep, exercising, eating healthy and making time for self-care to reduce stress.” When it comes to diet, she says, rather than looking for the one “magic food” that can boost your immunity, focus on eating a healthy and balanced diet. 

That said, there have been a number of studies examining the impact of certain nutrients on immune function. Here, CoveyClub takes a closer look at the latest research on diet and immunity, and talks to experts about steps you can take — beyond hand washing and social distancing — to reduce your risk of infection and keep your body’s defenses strong during this pandemic. 

Eat a Balanced Diet
“We have known for a long time that deficiency of certain nutrients is associated with higher risk for suppressed immunity,” says Wafaie Fawzi, DrPH, professor of nutrition, epidemiology, and global health at the Harvard T.H. Chan School of Public Health. “And there is also quite a bit of evidence on how good nutrition is associated with reduced risk of infection.” According to Dr. Fawzi, a healthy diet is not only associated with lower odds of acquiring infection, but also plays a role in one’s ability to fight disease once infected. 

Dr. Fawzi stresses the importance of consuming a diet rich in fruit and vegetables, whole grains, and healthy fats to ensure that you get all the vitamins and minerals needed to support immune function. Choose brightly colored produce like berries, apples, carrots, spinach, and tomatoes, which are high in flavonoids (naturally occurring antioxidant phytochemicals that help fight inflammation and tissue damage in the body) as well as vitamins A and C, both of which play vital roles in immune system health.  

Protein is also critical to immune function, so vegetarians should be mindful, especially now, that they are consuming adequate protein from plant sources like legumes, nuts, and seeds. Some experts suggest adding garlic and onions (which have antimicrobial properties) to your meals, as well as turmeric (which is anti-inflammatory) and probiotic foods like kimchi, yogurt, and tempeh, which keep your microbiome healthy and thus also support immunity.  

Consider Taking a Vitamin D Supplement
Several studies — including research on both the seasonal flu and the pandemic flu caused by H1N1 virus back in 2009 — have shown that vitamin D supplementation not only reduces the likelihood of developing respiratory tract infections, but is linked to fewer symptoms and quicker recovery in those who get infected. New research suggests that maintaining adequate levels of vitamin D may also reduce the severity of COVID-19 infections. Not only does vitamin D help the body develop antibodies to the novel coronavirus, and prevent it from spreading through the body, researchers say, but it can also reduce the likelihood of a “cytokine storm,” an overactive immune response that has led to many COVID-19 deaths.

Many adults are deficient in vitamin D, and staying indoors makes low blood levels of this vitamin even more likely, since the vitamin is produced by exposure to sunlight. (Deficiency is especially prevalent during the winter and early spring months.) One way to increase your vitamin D levels is to spend some time outside (though remember to avoid excessive sun exposure, which can lead to skin cancer). Some health experts suggest that taking a supplement containing 1000-2000 IU per day may be prudent at this time. (Note that this is well above the US Recommended Daily Allowance of 400 IU. That’s because the RDA is  based on the amount needed for bone health, according to Michael Puglisi, PhD, assistant extension professor in nutritional sciences at University of Connecticut. “That might not be optimal to modulate immune response.”) Vitamin D can also be found in fortified dairy products and cereals, fatty fish like tuna and salmon, and egg yolks. 

Consume Adequate Vitamin C and Zinc
Both vitamin C and zinc have been shown in studies to reduce the risk of respiratory infection, and to shorten the duration of illness and improve outcomes in those infected. Vitamin C plays a role in antibody production as well as in the growth and function of other immune cells. Zinc may prevent coronaviruses from entering cells, and appears to reduce coronavirus virulence. Clinical trials are even underway to test the benefits of intravenous vitamin C or intravenous zinc in the treatment of COVID-19 patients. 

Vitamin C can be found in citrus fruits, cruciferous vegetables like kale and broccoli, and bell peppers; sources of zinc include nuts, shellfish, red meat, and legumes. “Optimum diet is a priority, but with so much evidence that these nutrients are important in fighting off infections, it would be quite reasonable to take a multivitamin a day as added insurance,” says Dr. Fawzi. “Many of us, according to surveys, are not consuming adequate amounts of vitamins and minerals in our diets.” 

Get Plenty of Sleep
Sufficient sleep is key to keeping immune function strong. Not only does shorter sleep duration increase the risk of infectious illness, but getting adequate sleep also ensures the secretion of melatonin, which may play a role in reducing coronavirus virulence, according to experts at the Andrew Weil Center for Integrative Medicine. 

Exercise Regularly
“Regular exercise builds up your body’s anti-inflammatory responses over time, and plays a role in immune system regulation,” notes Dr. Puglisi. Experts recommend aiming for 30-45 minutes of moderate activity daily. There is some evidence that very intense training can actually suppress immunity, so don’t overexert yourself, especially if you are run-down. If you want to add intensity, Dr. Puglisi says, be sure to do so gradually, and with adequate rest. 

Stop Smoking
COVID-19 primarily attacks the lungs; smoking impairs lung function. The World Health Organization (WHO) just released a warning that smokers are more likely to develop severe disease with COVID-19. If that’s not enough to convince you, consider that the act of smoking itself — in which fingers come into contact with lips — makes smokers more vulnerable to infection, as they are more likely to transmit the virus from hand to mouth. 

WHO recommends that smokers take immediate steps to quit, and suggests trying nicotine replacement therapies, or reaching out to toll-free quit lines or mobile text-messaging smoking cessation programs. The good news: lung function increases within 2-12 weeks of quitting, while elevated heart rate and blood pressure drop within 20 minutes. Public health experts have warned that vaping and e-cigarettes also make people more vulnerable to severe complications of COVID-19, and may even be responsible for the higher number of young people diagnosed with the disease in this country. 

Manage your Stress
Psychological stress can also lower your defenses — but don’t let that add to your anxiety! Instead, try meditation, virtual yoga classes, or walks in nature, all of which can help you reach a calmer state. Limiting social media and news-watching might also be helpful, Dr. Puglisi adds. And lest you are tempted to turn to cannabis for stress-relief, note that smoking or vaping marijuana causes inflammation in the airways just as smoking or vaping tobacco does.  

Cut Back on Sugar and Alcohol
Though moderate drinking — say, one drink a day — is probably not problematic, says Dr. Fawzi, excessive alcohol is associated with higher risk of respiratory infections like pneumonia and tuberculosis. Should you get sick, however, it’s best to abstain, he says, since alcohol does have a dampening effect on the immune system. 

Refined sugars, too, have been shown to suppress the immune system — even hours after ingestion. So resist the urge to stress-eat and binge on sugary foods. Reducing your sugar intake will also reduce your risk of developing diabetes, which puts you at higher risk for complications of COVID-19. 

A Word of Caution
Remember that products that seem too good to be true probably are: Avoid supplements promoting wild health claims. Also keep in mind that you can have too much of a good thing. Megadoses of any nutrient are not recommended, public health experts say, and can even be harmful. Though nutritional supplements can fill in the gaps, they are not a substitute for a balanced diet based on nutrient-dense whole foods. “There is evidence for the importance of different nutrients,” says Dr. Fawzi, “but a healthy, varied diet that provides all the nutrients at a time is a much healthier approach.”