Pharmaceutical companies are working around the clock to develop vaccines and drugs for the prevention and treatment of COVID-19, the respiratory illness caused by the SARS-CoV-2 virus.
All of these things, unfortunately, take time. That’s why it is more important than ever to stay calm, do your best to avoid exposure, and support your immune system and your overall health so you’ll have the best chance of fighting off infection. In addition to getting plenty of rest, eating an anti-inflammatory diet, and managing stress, this support includes adopting a nutritional program that specifically addresses viral infections.
Recently, I joined forces with several of my colleagues on the Personalized Nutrition & COVID-19 Task Force of the American Nutrition Association to develop a paper with information and guidance for health professionals. It includes foods, nutrients, and supplements that have been shown in scientific studies to optimize the immune response and/or inhibit viruses—and is an invaluable resource.
Here are some important points from that paper that I want to share with you.
Treatment: Inhibiting Viral Replication
When you get sick from any viral infection—whether it’s a cold, flu, or the coronavirus—the virus invades your body by making copies of itself. This is called “viral replication.”
Researchers are trying to come up with drugs that treat the coronavirus by attacking “proteases,” which are enzymes required for viral replication. These drugs, called protease inhibitors, are currently used to treat HIV and other viral infections, and similar drugs are being tested on the SARS-CoV-2 virus.
Several natural compounds have been shown to have protease-inhibiting activity. They include vitamin C, riboflavin (vitamin B2), and glutathione, the body’s premier antioxidant produced in cells throughout the body.
A number of botanicals also inhibit proteases involved in virus replication: curcumin (turmeric), lutein, skullcap, andrographis, viola, bitter orange, hesperidin, kaempferol (spinach, cabbage, dill), naringenin (citrus), oleuropein and luteolin (olives), and catechin/ECGC (green tea).
I am not suggesting these compounds will stop the coronavirus, but they may well play a supporting role in treatment and prevention.
Optimizing the Body’s Immune Response
The majority of deaths linked with the coronavirus are not caused by the virus itself but by an overreaching, hyperinflammatory immune reaction—meaning your immune system goes into overdrive.
Whenever you’re sick, your immune system releases proteins called cytokines that help coordinate the immune response and trigger inflammation. In some cases of COVID-19, however, it overreacts, unleashing a barrage of cytokines. This “cytokine storm” causes excessive inflammation that damages not only the infected cells (which is what you want) but also healthy tissues in the respiratory tract, which makes breathing difficult.
Many of the drugs being used and tested to treat severe coronavirus disease target this cytokine storm. There are also several natural ingredients that hold promise as supportive therapies for curbing cytokines and the associated inflammatory response, including curcumin, bergamot, and flavonoids like resveratrol and luteolin.
Protective Nutrients and Supplements
The following food compounds, vitamins, minerals, and other supplements—which have demonstrated immune-enhancing properties and, in some cases, antiviral activity—provide an excellent foundation for protecting against infection and supporting overall health and wellbeing.
Vitamins That Are Vital for Immune Health
Vitamin A: This vitamin is renowned for its role in immune function. In addition to supporting the mucosal tissues throughout your body that keep germs at bay, it also helps to regulate the immune system directly.
Good food sources of vitamin A include liver, cod liver oil, black-eyed peas, sweet potatoes, spinach, and broccoli. Supplements include vitamin A (retinol) and “pro-vitamin A” (beta-carotene), which is converted in the body to make vitamin A as needed.
Vitamin C: Nobel Laureate Linus Pauling popularized vitamin C’s benefits for warding off the common cold (a viral infection) and enhancing immunity. Research bears this out. This vitamin is an essential nutrient for optimal white blood cells and overall immune function.
In fact, intravenous (IV) vitamin C—which can be administered in doses much higher than tolerated orally—is showing promise in the treatment of coronavirus disease, as it protects against the hyperinflammatory cytokine storm that may occur as the immune system fights off severe infection.
Good sources of vitamin C include citrus fruits, kiwi, bell peppers, spinach, tomatoes, and other fruits and vegetables are abundant in vitamin C. Although megadosing has not been shown to reduce the risk of the coronavirus, a daily dose of 400–1,000 mg is a good idea. Look for a supplement that also contains citrus bioflavonoids.
Vitamin D: Clinical trials involving more than 11,000 study subjects of all ages have demonstrated that supplemental vitamin D protects against acute respiratory tract infections. Most Americans have suboptimal vitamin D status. Bringing your blood level into the optimal range of 40–80 ng/dL is a prudent step for reducing your risk of all respiratory infections.
Sun exposure is vital for maintaining adequate stores of vitamin D levels. Nevertheless, deficiencies are common, especially in the winter. I recommend taking 1,000 IU of vitamin D3 daily. Better yet, have your blood level tests and take enough to keep it in the optimal range.
Vitamin E: Although vitamin E has no proven antiviral effect, it is one of the body’s most important fat-soluble antioxidants and provides essential protection against free radical damage and inflammation in the lungs and other tissues. The majority of people in this country fail to get an adequate dietary intake of vitamin E, and this can impair the immune response and increase viral load.
Although vitamin E is found in nuts, seeds, oils, and other foods, it is nearly impossible to get adequate amounts from food. Supplementation is imperative. Look for natural vitamin E (d-alpha tocopheryl), preferably with additional forms of vitamin E such as tocopherols and tocotrienols. The recommended dose is 100-300 IU of mixed vitamin E compounds.
Zinc: This mineral has a well-earned reputation as an immune booster. Even modest zinc deficiency can depress the activity of natural killer cells, macrophages, and other immune cells—and very low zinc status is linked with an increased risk of pneumonia and other infections in older people.
Zinc-rich foods include oysters, crab, and lobster as well as some nuts and beans. A daily dose of 15 mg, found in many multivitamins, is recommended. Some studies suggest that zinc lozenges or syrup inhibits the binding and replication of the rhinovirus, which causes the common cold, and can reduce duration and severity.
Selenium: Not only a powerful antioxidant in and of itself, selenium is also needed for the production of glutathione, the body’s most abundant antioxidant. This trace mineral has been shown to slow the replication of some viruses, although its effects on the coronavirus are unknown.
Just one Brazil nut contains more than the RDA of selenium. Other sources include tuna, shellfish, eggs, and sunflower seeds. I also recommend supplemental selenium, 100 mcg per day.
Potassium: Although supplemental potassium has no definitive role in coronavirus prevention, it has benefited patients who are hypokalemic (low blood level of potassium) due to severe coronavirus illness.
Supplements aren’t recommended because potassium is abundant in fruits and vegetables. Adequate intake of plant foods will ensure that you’re getting enough of this important mineral.
Botanicals & Phytonutrients
Oil of Oregano: Best known as a culinary spice, oregano contains carvacrol and other compounds that have proven effective against respiratory viruses, including influenza viruses.
You cannot get therapeutic amounts of these compounds in food—even in all the Italian dishes my family cooks that often include oregano. However, oil of oregano is available in tinctures and capsules. Use as directed.
Quercetin: Lab and animal studies suggest that this flavonoid has protease-inhibiting activity. Quercetin also helps restore protective antioxidants in the lungs that are reduced by viral infections.
Red onions, leafy greens, chili peppers, apples, grapes, tea, and red wine are the richest food sources of quercetin. When using in supplement form, take it with bromelain or vitamin C for enhanced absorption. The suggested daily dose is 500 mg.
Coconut oil: Lauric acid in coconut oil, as well as monolaurin which is derived from lauric acid, have antiviral effects. Research suggests these compounds discourage the adherence of viruses from binding to cell membranes and have been proposed as a supportive therapy for the coronavirus.
To get significant amounts of lauric acid, you have to use unrefined virgin coconut oil, as opposed to refined, filtered oil or MCT. Monolaurin is available as a supplement; 500 mg is a reasonable dose.
Other Supportive Supplements
Melatonin: Best known as the “sleep hormone,” melatonin is also a potent antioxidant with proven benefits for immune function. Early research suggests it may be beneficial in the treatment of viral infections.
When taken for sleep, the usual dose is 3–6 mg 30 minutes before bedtime. Large doses have been used in studies involving immune function.
Protein: Optimal immune function requires an adequate protein intake. Animal foods, as opposed to plant proteins, are rich in amino acids such as taurine, carnosine, and creatine that appear to be particularly protective. Elderly people, the group most likely to be protein deficient, are also the most likely to be immunocompromised.
Supplementing with a high-quality protein supplement is recommended for anyone with inadequate protein intake. Undenatured whey protein, abundant in dairy, is a good one, as it contains lactoferrin, which has been shown to inhibit some viruses.
The intent of the American Nutrition Association’s Personalized Nutrition & COVID-19 Task Force in writing this comprehensive review was to provide health care professionals with an overview of the current science to assist them in devising strategies for their patients.
However, I firmly believe that the better informed you are—and the more proactive you are about optimizing your immune function—the more likely you are to stay healthy, weather the coronavirus crisis, and come out strong on the other side.