In these sobering times, we must use every weapon in our arsenal against invasive viruses, including often-overlooked natural remedies with antiviral properties. As is also the case with pharmaceutical agents, natural approaches have not been shown to stop an aggressive virus in its tracks, but they may ameliorate symptoms. “Nutrition and supplementation are unlikely to prevent an infection, but they may help prevent the infection from becoming symptomatic or severe,” explains Leo Galland, M.D., a global leader in functional medicine and author of Power Healing: Use the New Integrated Medicine to Heal Yourself.

Eating healthy foods, sleeping seven to nine hours a night and exercising at least 150 minutes a week are also key in fortifying our natural defenses against viruses. Steps still necessary for COVID-19 protection include hand-washing, mask-wearing, social distancing and sterilizing objects and surfaces.

Baseline Protectors

Scientists report that some vitamin and mineral deficiencies appear to be linked to poor COVID-19 outcomes, while adequate levels help combat other viruses. Consumer Lab, which provides comprehensive research overviews and information on nutritional products, lists these natural supplements as potential aids against COVID-19, although at this early stage, none have been proven to work:

Vitamin D: According to Galland, vitamin D “stimulates your immune system to produce factors called defensins and cathelicidins that kill viruses.” People with levels below 30 nanograms per milliliter (ng/mL) were 45 percent more likely to test positive for the coronavirus and 95 percent more likely to be hospitalized, Israeli researchers found. Getting three 30-minute sessions of sun exposure a week and eating D-fortified foods raise levels, and supplementing with up to 2,000 international units daily is generally considered safe. 

Zinc: “Zinc throws a wrench in the viral replication machine and helps fight infections by boosting the production of antibodies,” says Nicole DeMasi, an integrative dietitian nutritionist in Los Angeles. Zinc lozenges may ward off the coronavirus in the upper respiratory tract. The recommended dosage is 15 to 30 milligrams (mg) a day for up to two weeks. 

Vitamin C: A cup of orange juice, tomato juice or a kiwi supplies most of the minimum recommended intake of vitamin C, a vital supplement for white blood cells that fight viral infections. Supplementing with 1,000 mg daily is also safe. Intravenous megadoses are being studied for critically ill COVID-19 patients, but no evidence exists so far that higher levels prevent infections, reports Consumer Lab.

Potassium: A critical antiviral mineral and electrolyte, low levels of potassium were found in 61 percent of 175 Chinese patients hospitalized with COVID-19, making them more prone to heart damage, reports the Journal of the American Medical Association. Foods that boost levels include potatoes, squash, lentils, spinach, avocados, bananas and raisins.

When choosing supplements proven to be effective, “Much of what we know and can apply is based on our previous research on viruses of the past,” says Monisha Bhanote, M.D., an integrative physician in Jacksonville Beach, Florida. Here are some good choices.

Melatonin: Known best as the hormone that regulates sleep, melatonin also supports antiviral immunity and helps control inflammation in viral infections. A study of 11,672 people tested for COVID-19 found that those taking supplemental melatonin were less likely to test positive, and a clinical study is underway to see if 2 mg a day helps protect healthcare workers. Typical dosages range from 0.3 to 3 mg. 

Licorice Root Extract: This herb contains a substance called glycyrrhizin that makes it hard for a virus to attach to and invade a cell and hinders its ability to replicate, slowing the spread from one cell to another. Chinese doctors used it with other traditional herbs to combat COVID-19, and studies have shown it effective against an earlier coronavirus, as well as against HIV, herpes, viral hepatitis and respiratory infections. For dosage, follow package directions. People with high blood pressure, congestive heart failure, kidney disease or low potassium levels are advised against its use.

Astragalus: Known as huang qi, astragalus “is one of the most powerful herbs used in Chinese medicine for people with weakened immune systems,” says Tsao-Lin Moy, a New York City acupuncturist and herbalist. It’s best taken as a hot or cold tea using tea bags or the root itself.

Andrographis: This herb has long been used for colds and throat infections in China and India, and may prevent flu viruses from binding to cells. In a Swedish study, flu patients that took an andrographis extract along with Siberian ginseng recovered more quickly with fewer complications than those given a U.S. Food and Drug Administration-approved flu medication. Because of its potency, it’s best to consult a health practitioner to avoid interactions. The recommended dosage is 400 mg twice a day.

To lower the inflammation linked to poor viral outcomes, Bhanote recommends a predominantly whole foods diet with at least five to seven servings of vegetables and two to three servings of fruit a day. 

 

Quercetin-rich foods, such as apples, onions, broccoli, raspberries, parsley and celery are especially important, she says, because the bioflavonoid enhances zinc’s antiviral actions: “It functions as a zinc ionophore, chelating zinc and transporting it into the cell cytoplasm.” Quercetin can also be taken as a supplement in doses ranging between 500 and 1,000 mg daily.

Garlic has potent antiviral and antibacterial properties, and can be cooked into food, eaten raw in salads and dressings or obtained from capsules of allicin, the active component.

Green tea has epigallocatechin gallate, a compound with “a wide range of antiviral activity, especially in the early stages of infection, by preventing viral attachment and entry into the cell,” says Bhanote. Aim for three to five cups a day.