Zinc is an essential element for all living organisms. It is necessary and indispensable for human, animal and plant life. Aside from iron, zinc is the most common mineral found in your body; necessary for the function of every one of your cells. The body needs zinc to carry out normal metabolism and ensure the proper function of the reproductive, cardiovascular, and nervous systems.
Zinc insufficiency may be considered as a risk factor for infectious diseases. Deficiency in zinc is a significant risk factor for the development of pneumonia, which can be a consequence of COVID-19.
Antiviral Properties of Zinc
Coronavirus Disease 2019 (COVID-19) represents the largest current health challenge for the society. It is well known that zinc possesses a variety of direct and indirect antiviral properties, which are realized through different mechanisms.
Zinc possesses several antiviral effects which are realized through the generating both innate and acquired immune responses, facilitation of the normal functioning of innate immune system, stabilization of cell membrane inhibiting the entry of the virus, and inhibition of viral replication and viral attachment.
Zinc may also act in a synergistic manner when co-administered with the standard antiviral therapy, as was demonstrated in patients with hepatitis C, HIV, and SARS-CoV-1.
For decades, scientists have known that zinc can block the replication of rhinoviruses responsible for respiratory infections in people, including the common cold. Some common colds are caused by coronaviruses. No studies have looked specifically at whether zinc helps fight colds caused by coronaviruses. There is some evidence that taking zinc lozenges or syrup starting on the first day of a cold can help you get over a cold faster.
Zinc may inhibit viral replication by alteration of the proteolytic processing of replicase polyproteins and RNA-dependent RNA polymerase in rhinoviruses, HCV, and influenza virus, and diminish the RNA-synthesizing activity of nidoviruses, for which COVID-19 belongs. Therefore, it may be hypothesized that zinc supplementation may be of potential benefit for prophylaxis and treatment of COVID-19.
Higher levels of zinc in cells help block the reproduction of rhinoviruses and stimulate interferon alfa production. This signaling molecule prompts nearby cells to initiate their anti-viral defenses.
Zinc , once inside the cell is thought to neutralize the virus. Chloroquine softens the cell membrane and acts as a zinc ionophore (increasing the ion permeability of the cell membrane), binding to zinc ions and carrying them into the cell where it then stops viral replication.
Zinc ionophores transport extracelluar Zn2+ ions across a cell membrane, and have been studied for their anti-viral and anti-cancer activities. Zinc ionophores include Chloroquine derivatives and Quercetin .Zinc ionophores have been shown to inhibit replication of various viruses in vitro as HCV,HIV, MERS coronavirus , Rhinovirus , SARS coronavirus , and Zika virus .
Quercetin is a natural antioxidant pigment present in many fruits and vegetables. Quercetin is contained in abundance in apples, honey, raspberries, onions, red grapes, cherries, citrus fruits, and green leafy vegetables. Among vegetables and fruits, quercetin content is highest in onions
Zinc and the Immune System
There are more than 300 different enzymes that require zinc to function normally. Researchers believe that 3,000 proteins (out of approximately 100,000) have this vital mineral. Zinc may directly regulate DNA synthesis. Zinc acts as a co-factor for important enzymes involved in the proper functioning of the antioxidant defense system. Chronic zinc deprivation generally results in increased sensitivity to oxidative stress.
Zinc is important for cellular growth, cellular differentiation and metabolism. Zinc also influences hormonal regulation of cell pision. Zinc also plays a role in hormone release .Zinc is crucial to thyroid hormone metabolism, and reduced thyroid function is strongly related to low serum zinc levels.
It also plays a major role in properly managing thyroid hormone receptors in the hypothalamus. Without this mechanism, the body may incorrectly gauge that it has sufficient levels of thyroid hormone and in turn decrease their production, leading to hypothyroidism.
Zinc supports the production and maturation of white blood cells, which are the major players in the immune system. There are multiple types of white blood cells, some of which make antibodies, capture and destroy pathogens, and return the immune system to normal after an infection.
Zinc helps to regulate inflammation. While an inflammatory response is necessary to fight infection, the overproduction of pro-inflammatory cytokines early in the infection is responsible for some of the worst symptoms of COVID-19. Zinc may have an anti-inflammatory effect in pneumonia, limiting the damage to lung tissue.
Zinc Deficiency
Zinc deficiency is ranked as the 5th main risk factor in causing diseases worldwide. According to the World Health Organization (WHO) around 31% of the world population is deficient in zinc. Zinc deficiency reduces growth and weight gain in infants and young children. The risk of zinc deficiency is observed in more than 1.5 billion people in the world. In past studies, the WHO reported that zinc deficiency may be responsible for 13% of all lower respiratory tract infections, most often pneumonia and flu, in children younger than 5 years. Zinc deficiency is common in the elderly, who are most likely to be severely affected by coronavirus.
The causes of acquired zinc deficiency inadequate dietary intake, decreased zinc levels in maternal breast milk, receiving total parenteral nutrition without any supplementation of zinc, alcohol use, gastrointestinal affections, malabsorption syndromes and chronic debilitating conditions .
Zinc deficiency results in dysfunction of immunity and increases the susceptibility to infection. Zinc deficiency is associated with increased susceptibility to infectious diseases caused by bacterial, viral, and fungal pathogens, and may be caused by some diseases (e.g., liver cirrhosis or inflammatory bowel disease), aging, and lifestyle-associated factors (e.g., vegan/vegetarian diet) . In such cases, appropriate administration of zinc supplement in sufficient therapeutic doses has a potential either to restore depleted immune cell function or to improve normal immune cell function.
Increasing concentrations of atmospheric carbon dioxide lower the content of zinc and other nutrients in important food crops. Populations who are at highest risk for zinc deficiency receive most of their dietary zinc from crops.
Sources of Zinc
The foods high in zinc are meat, oysters, sesame seeds, flax seeds, pumpkin seeds, whole grains, cocoa powder, mushrooms, poultry and egg yolk. Legumes contain high amounts of zinc. However, they also contain phytates, which reduce its absorption
High zinc fruits include avocados, blackberries, pomegranates , raspberries, guavas, cantaloupes, apricots, peaches, kiwifruit, and blueberries.
Zinc supplementation may be of benefit for prophylaxis and treatment of COVID-19. Zinc supplements are most effective if they are taken at least 1 hour before or 2 hours after meals.
Too much zinc can make you sick. Too much zinc can actually lower your immune response. Zinc can also interact with other supplements, particularly copper, and medicines. It is also worth noting that consuming excess zinc can have adverse effects, including nausea, loss of appetite, and stomach cramps. Over the long-term, too much zinc has associations with low immunity.
By: Dr Magdy Badran
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