For decades, over-the-counter zinc, preferably chelated or protein-bound for better absorption, has relieved viral symptoms caused by colds and flu. Zinc’s well-established antiviral mechanisms reduce viral entry into cells, inhibit RNA polymerase that viruses like Covid-19 require to multiply inside human cells, and improve the body’s immune responses. Zinc appears to reduce the number of ACE-2 enzyme receptors on cell walls. It alters the configuration of ACE-2 to reduce viral binding. Because zinc deficiency is strongly associated with increased severity of viral symptoms, including Covid-19, a zinc supplement may help prevent and treat Covid‐19. Zinc may also minimize the loss of taste and smell sensations that often accompanies Covid-19 infections.
Quercetin is a natural compound found in red grapes, citrus fruits, and onions. It binds zinc ions and transports them across cell membranes to where it is most needed, inside the cells. Once inside, zinc lowers RNA polymerase enzyme activity that would otherwise increase the multiplication of RNA viruses like Covid. Quercetin has antioxidant and anti-inflammatory properties of its own. It reduces the levels of inflammasomes and interleukin-1 (IL-1). Cytokine IL-1 levels are directly tied to mortality from Covid-19. A retrospective analysis of IL-1 inhibitor anakinra (Kineret) use among 62 patients given 5 mg/kg twice a day showed a 50% reduction in hospital deaths from Covid-19 than 55 patients given IL-6 inhibitors. Anakinra is likely more potent than quercetin but may have direct benefits. Like zinc, quercetin is widely available at pharmacies and health food stores.
In Spain, researchers retrospectively reviewed plasma zinc levels of 249 patients admitted to a hospital with Covid-19 in the spring of 2020. On arrival, the average plasma zinc level was 61 mcg/dL. The initial zinc level for the 21 patients (8%) who died from Covid averaged just 43 mcg/dL, compared to 63 mcg/dL for those who survived. People with plasma zinc below 50 mcg/dL at admission were 2.3 times more likely to die in the hospital (p = 0.034) than those whose plasma zinc level was 50 mcg/dL higher. Each mcg/dL increase in plasma zinc at admission was associated with a 7% lower risk of dying in the hospital. (p = 0·0049).
Fortunately, zinc levels can be raised in cells to healthier levels when given for two weeks at 25 mg chelated or bisglycinate zinc plus 500 mg of quercetin per day. With a suspected or proven infection, doses of 25 or 50 mg chelated (protein-bound) zinc taken with 500 mg quercetin twice a day improves zinc transport into cells. Take zinc with food for less GI irritation and stop once symptoms resolve.