Zinc lowers the COVID-19 mortality rate
The immune system is of vital importance to our ability to react to a COVID-19 infection. Most people don’t get any symptoms or only have mild ones, whereas the infection can become complicated and potentially life-threatening for certain exposed groups of people. Numerous studies have shown that our immune defense depends on different vitamins and minerals to function optimally. Now, a meta-analysis has shown that zinc supplementation can lower the mortality rate among COVID-19 patients. Many older people, chronically ill patients, and other vulnerable groups tend to lack zinc. This is a problem because the nutrient is not only essential for a well-functioning immune defense but also protects cells and tissues against damage caused by oxidative stress.
The new meta-analysis, which is published in Cureus, compared symptoms and mortality among COVID-19 patients that were given supplements of zinc or placebo. The researchers trawled databases such as PubMed/Medline, Cochrane, Web of Science, and CINAHL in search of published articles by using search words such as “zinc”, “COVID”, “sars-cov-2”, “COVID-19”, or “coronavirus”. They found a total of 1,215 articles and ended up using five of them to assess the different symptoms. They used the common guidelines (PRISMA) for use of meta-analyses.
Their meta-analysis revealed that COVID-19 patients who were given zinc had lower mortality compared to non-supplemented patients. As for the symptoms, there did not appear to be any difference between the two groups. Nonetheless, the new data show that zinc supplementation is linked to lower COVID-19 mortality. According to the scientist, these results are very promising, as zinc is an inexpensive and convenient therapy form for improving survival.
When do COVID-19 infections become complicated?
A well-functioning immune defense normally fights a COVID-19 infection and leaves some form of immunity without causing any symptoms. It is also quite normal to have mild or moderate symptoms such as a fever, tiredness, sore throat, a cough, or loss of one’s sense of taste and smell. If, however, the immune defense overreacts it may result in cytokine storm and hyperinflammation, which causes oxidative stress. This is potentially dangerous because free radicals attack cells and tissues. Blood-coagulating factors may also be activated. It is not the virus itself that is the threat but the unhinged immune reaction, and this may eventually lead to acute respiratory distress syndrome (ARDS), organ failure, and death. Moreover, comorbidities such as hypertension, diabetes, COPD (chronic obstructive pulmonary disease), overweight, and cardiovascular diseases increase the risk of a COVID-19 infection becoming life-threatening. These conditions are characterized by a derailed immune defense and chronic low-grade inflammation.
How does zinc protect against COVID-19?
Zinc is one of the most important trace elements and is involved in a host of metabolic processes that play a key role in the immune defense. Zinc is particularly important for the innate immune defense and for our macrophages that fight most microbes before they start replicating. Zinc is also important for our adaptive immunity and its T and B cells that are more specialized and are responsible for making antibodies. Zinc is also involved in the immune system’s communication and regulation of the inflammatory processes. Zinc deficiency is proven to increase the release of pro-inflammatory cytokines such as IL-1β, IL-6, and TNF- α (tumor necrosis factor α).
Zinc also protects against other types of viruses such as the common cold, and it is able to lower the risk of getting infected and reduce the number of sick days. It is proven that intracellular zinc concentrations prevent COVID-19 from replicating and spreading in the body. Zinc is also believed to dial down the activity of the cells’ COVID-19 receptors (ACE), thereby making it more difficult for the virus to enter the cells and start dividing.
Another important function of zinc is its supportive role in the powerful SOD (Superoxide Dismutase) antioxidant that protects cells and tissues against oxidative stress.
Finally, zinc is important for our sense of smell and taste, and these senses can be affected by virus infections.
In addition, zinc appears to improve the effect of drugs such as chloroquine and hydroxychloroquine that are used to treat complicated COVID-19 infections.
Zinc also works closely together with vitamin D that supports the immune defense in different ways. Vitamin D improves the uptake of zinc in our digestive tract, and it supports different zinc-dependent functions in our cells.
Zinc requirements and supplementation
The recommended daily intake level for zinc in Denmark is 10 mg. In the case of an infection, however, the need increases because of all the different zinc-dependent functions that need more of the nutrient. EFSA (the European Food Safety Authority) has set 25 mg as the safe upper intake level for daily zinc intake. It is perfectly safe to take even more for brief periods. Prolonged intake of high doses may result in an iron or copper deficiency, however, as these two minerals are zinc antagonists.
- Zinc is found in shellfish (especially oysters), liver, meat, eggs, dairy products, wholegrains, kernels, walnuts, legumes, and vegetables.
- Zinc from animal food sources has better absorption than zinc from plant sources.
- The body’s zinc absorption may be impaired by a vitamin D deficiency, low stomach acid, ageing, various gastrointestinal diseases, excessive alcohol intake, birth control pills, diuretics, and antacids.
- An estimated one billion people worldwide lack zinc.
Spencer Z Rheingold et al. Zinc Supplementation Associated With a Decrease in Mortality in COVID-19 Patients: A Meta-Analysis. Cureus. 2023
Ashton Amos, Mahammed S. Razzaque. Zinc and its role in vitamin D function. Current Research in Physiology. 2022
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