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By Wendy Pecoraro, MSN, APRN, DipACLM

The novel coronavirus (COVID-19) has prompted several questions from my patients about what they can do to protect themselves and support their immunity. With the understanding that there is no treatment or cure currently, I provide the standard recommendations, but there are those who want to take a more proactive approach to stay healthy during these challenging times.

Immunity is supported by exercising, getting quality sleep, eating whole foods, practicing mindfulness, and spending time outdoors. It is also important, during this time of social distancing and stay-at-home mandates, to avoid those foods that we might turn to for comfort or to overcome boredom. Alcohol reduces the number and function of three important kinds of cells in your immune system–macrophages, T and C cells and sugar suppresses the immune function of phagocytes for up to five hours post-ingestion.

For the purposes of this article, I’m going to focus on immune support through nutrients. As we all know, the best way to get high quality nutrients is through a well-balanced plant-based diet. Depending on how long stay-at-home directives are in place that call for one grocery store visit per week, a variety of fresh foods may not be as available as they are under normal circumstances. Consequently, patients may have to rely on supplementation, at least for the time being.

Immune Response

I want to start with a review of the immune system response to infection. This will help patients understand the reason behind the supplement recommendations.

The initial function of acute inflammation is to recruit leukocytes from circulation, primarily neutrophils. These are followed by monocytes that differentiate into macrophages or dendritic cells. The inflammatory response proceeds with the degranulation and activation of local mast cells and macrophages, and the release of a variety of pro-inflammatory mediators, including bioactive amines (histamine and serotonin), cytokines (IL-1 and TNF-α), and chemokines.

This causes vasodilation and increased vascular permeability that allow the deposition of leukocytes and plasma at the site of injury or infection. Neutrophils then move along a chemotactic gradient created by cytokines and components of the complement pathways. Ideally, the enlisted neutrophils will attempt to destroy the inflammatory agent and eventually elicit resolution and healing.

However, if the infection is overwhelming, far too many immune cells are caught in an endless loop of calling even more cytokines, resulting in a deadly cytokine storm. The cytokine storm ends up inflaming the tissue of the lungs and crowding air passages, causing the Severe Acute Respiratory Syndrome (SARS) that we’ve seen in severe cases of COVID-19 infection.

Specific Nutrients and Immunity

The following nutrients support many vital functions throughout the body, listed below are the ways they specifically support the immune system:

Vitamin B Complex

Recommended dosage: 1 tablet daily

B6

Food Sources: Beef liver, chickpeas, tuna, salmon, rice, cereals and onions.

The body needs B6 in order to absorb vitamin B₁₂ and to make red blood cells and cells of the immune system. Vitamin B₆ helps the body to make several neurotransmitters like serotonin, chemicals that carry signals from one nerve cell to another. Serotonin is only synthesized by tryptophan and this conversion of tryptophan to serotonin occurs in the presence of pyridoxal phosphate which is a vitamin B₆ derivative.

B9

Food Sources: Lettuce, avocado, spinach, kidney beans, shellfish, salmon, egg, rice, and peanuts.

Vitamin B₉ or Folic acid (folate) also plays a role in immunity enhancement. It is commonly a key role player in the biosynthesis of nucleic acids, proteins, blood cells, and nervous tissues.

B12

Food Sources: Milk, yogurt, cheese, egg, trout, cereals

It aids in the metabolism of every cell of the human body, especially affecting DNA synthesis, fatty acid, and amino acid metabolism. It is also involved in B-cell synthesis and T-cell multiplication. In animal models, a deficiency of B₁₂ caused immune response reduction during viral and bacterial infections. 

Vitamin C

Recommended dosage: 60 milligrams per day.

Food sources: Tomato, cabbage, oranges, cantaloupes, green and red pepper, spinach and green peas.

Anecdotal evidence supports up to 2,000 milligrams per day. Vitamin C has been studied and is thought, in critical patients, to decrease the amount of time they require artificial ventilation. It is currently being studied in intensive care units with septic patients and COVID-19 patients. While getting sufficient Vitamin C can help maintain a healthy immune system, there is no evidence to support that getting more than the daily requirement can prevent infection.

Too much vitamin C may be linked to kidney stones. Do not take vitamin C with iron supplements. Use care when taking vitamin C and acetaminophen. Data on the common cold and other viruses is mixed. Recommendation is less than two grams per day to avoid side effect of diarrhea.

Vitamin D3

Recommended dosage: 5,000 international units daily 

Food sources: Milk, yogurt, egg, cheese, cod liver oil, orange juice, salmon, and tuna.

The beneficial effects of vitamin D on protective immunity are due in part to its effects on the innate immune system. It inhibits B cell proliferation and blocks B cell differentiation and immunoglobulin secretion. Vitamin D additionally suppresses T cell proliferation.

Vitamin E

Recommended dosage: 15 milligrams per day

Food sources: Sunflower, safflower, wheat germ, peanuts, tomato, spinach, and broccoli.

Proper vitamin E at supplemental levels have been shown to enhance cell-mediated and humoral immune responses in various species of animals. Increased lymphocyte proliferation, immunoglobulin levels, antibody responses, natural killer (NK) cell activity, and interleukin (IL)-2 production have been reported with vitamin E supplementation

Elderberry

Recommended dosage: 15 milliliters of syrup four times a day for four to five days

Food sources: Elderberry syrup

Sambucol is a standardized black elderberry extract with antiviral properties, especially against different strains of influenza virus. Sambucol was shown to be effective in vitro against 10 strains of influenza virus. In a double-blind, placebo-controlled, randomized study, Sambucol reduced the duration of flu symptoms to three to four days. Convalescent phase serum showed a higher antibody level to influenza virus in the Sambucol group, than in the control group.  

Magnesium

Recommended dosage: 400 milligrams twice a day

Food sources: Almonds, spinach, potatoes, and kidney beans.

Several groups leading in nutrition and immunology have shown evidence that magnesium plays a key role in the immune response. It functions as a co-factor for immunoglobulin synthesis, C′3 convertase, immune cell adherence, antibody-dependent cytolysis, IgM lymphocyte binding, macrophage response to lymphokines, and T helper–B cell adherence.

In some people, magnesium might cause stomach upset, nausea, vomiting, diarrhea, and other side effects. Large doses might cause too much magnesium to build up in the body, causing serious side effects including an irregular heartbeat, low blood pressure, confusion, slowed breathing, coma, and death.

Quercetin

Recommended dosage: 1,000 milligrams per day.

Food sources: Apples, berries, Brussels sprouts, cabbage, cauliflower, collard greens, kale, turnips, capers, grapes, onions, shallots, tea, and tomatoes, as well as many nuts and seeds.

Several studies in vitro using different cell lines have shown that quercetin inhibits lipopolysaccharide (LPS)-induced tumor necrosis factor α (TNF-α) production in macrophages and LPS-induced IL-8 production in lung cells. Quercetin inhibits production of inflammation-producing enzymes over a two- to three- week period.

The literature is supportive of the anti-pathogenic capacities of quercetin when it is cultured with target cells and a broad spectrum of pathogens including URTI-related rhinoviruses, adenoviruses, and coronaviruses. The future challenge is to investigate optimal benefits of quercetin, especially to the recommendation for the protracted intake.

When taken by mouth, quercetin can cause headache and tingling of the arms and legs. Very high doses might cause kidney damage and prolonged bleeding time.

Zinc

Recommended dosage: 15 milligrams per day

Food Sources: Whole grains, milk, oysters, red meat, and poultry, chickpeas, and nuts such as cashews and almonds.

Zinc is crucial for normal development and function of cells mediating nonspecific immunity such as neutrophils and natural killer cells. Zinc deficiency also affects development of acquired immunity by preventing both the outgrowth and certain functions of T lymphocytes. Zinc functions as an antioxidant and can stabilize cell membranes.

In high doses, zinc may cause side effects that range from nausea and vomiting to reduced immune function or reduced iron function. Zinc nasal gel may result in loss of smell.

While all these supplements support immune function in different ways, because of their potential side effects, broad supplementation is not recommended. An approach tailored to the specific needs of each patient is the safest approach. Aside from the guidance of frequent handwashing, social distancing, and wearing masks when out in public, an integrative approach is ideal. A tailored supplement prescription, exercise, quality sleep, whole food, mindfulness and the great outdoors are the best way to support your patients through the COVID-19 pandemic.

References

Chirumbolo, S., Bjørklund, G., Sboarina, A., and Vella, A. (2017). The Role of Vitamin D in the Immune System as a Pro-survival Molecule. Clinical Therapeutics. Retrieved from: https://www.clinicaltherapeutics.com/article/S0149-2918(17)30235-7/fulltext

Tiralongo, E., Wee, S. and Lea, R. (2016). Elderberry Supplementation Reduces Cold Duration and Symptoms in Air-Travellers: A Randomized, Double-Blind Placebo-Controlled Clinical Trial. Nutrients. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4848651/

Yang, J., Chaudhry, M, Wang, S., Hongan, L., and Yin, Y. (2016). Nutrients Review Quercetin, Inflammation and Immunity. Nutrients. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4808895/

Editor’s note: Supplementation and nutrient support are for general health promotion and practitioners cannot claim any supplement can treat or cure COVID-19. Click here for more information and ongoing COVID-19 updates for integrative healthcare professionals.