Zinc is a critical microelement required for various vital biological activities due to its role as a transition metal, cofactor, structural component, and signaling molecule . Zinc has a significant role in respiratory tract antiviral defense and immunological modulation . This essential trace element aids in the synthesis and maintenance of immunological enzymes, including superoxide dismutase 1 and 3, which play a crucial role in the development and function of T cells . Several meta-analyses and systematic reviews indicated that zinc might help lower the prevalence and incidence of pneumonia in children, the mortality rate in adults with severe pneumonia, and the duration of the common cold in adults . Proper dietary intake of this trace element may help prevent and treat respiratory infections more effectively . A zinc deficiency has been shown to result in both humoral and cell-mediated immunity dysfunction, making individuals with low zinc levels more susceptible to respiratory viruses [2,3].
Zinc plays a vital role in the immune system’s defense against viruses that infect the respiratory tract. It functions in three primary ways: catalytic, structural, and regulatory . It helps maintain the integrity of the respiratory epithelial barrier, which is constantly exposed to pathogens in the air . A deficiency of zinc in airway epithelial cells can affect structural proteins and increase the permeability of the respiratory barrier . Zinc also regulates inflammation in the respiratory system and promotes the development of CD8+ cytotoxic T lymphocytes, which are crucial for the immune response to respiratory viruses . Insufficient zinc intake can negatively impact the immune function, particularly of Th1 cells, and the production of specific cytokines .
A deficiency of zinc has been linked to 16% of all deep respiratory infections globally, suggesting a correlation between zinc deficiency and the risk of infection and severe disease with COVID-19 and other viruses, as well as the potential benefits of zinc supplementation . Recent research has demonstrated how combining nitazoxanide, ribavirin, ivermectin, and zinc supplementation can effectively eliminate SARS-COV-2 . Studies have also found that zinc can decrease lower respiratory tract infection symptoms in COVID-19 patients, possibly inhibiting viral uncoating, binding, and replication . However, there is still a limited number of studies focusing on the role of zinc-dependent proteins in the fight against SARS-COV-2 infection.
As an essential trace element, zinc plays a crucial role in the antiviral immune response and regulation of the immune system in the respiratory tract. Zinc modulates the inflammatory response by inhibiting the activation of pro-inflammatory cytokines and the replication of various viruses, including COVID-19. Clinical studies have presented compelling evidence highlighting the importance of adequate zinc levels in preventing infection by respiratory viruses. Research has also shown that zinc reduces inflammation while providing antioxidant protection, protecting the lungs from harm, and reducing the risk of viral infections . A zinc deficiency may contribute to an increased susceptibility to infection and worsen the outcome of COVID-19 . However, more research is needed to establish the best dosage and duration of zinc supplementation for respiratory viruses. Given the crucial role of zinc in preventing viral infections and regulating the immune system in the respiratory tract, more awareness of this essential trace element should be raised.
- Adrean, S. D., Schmitt, K., Ng, C., Pirouz, A., Ramkumar, H. L., & Grant, S. (2022). Does Prophylactic Oral Zinc Reduce the Risk of Contracting COVID-19?. Cureus, 14(10), e30881. https://doi.org/10.7759/cureus.30881
- Alexander, J., Tinkov, A., Strand, T. A., Alehagen, U., Skalny, A., & Aaseth, J. (2020). Early Nutritional Interventions with Zinc, Selenium and Vitamin D for Raising Anti-Viral Resistance Against Progressive COVID-19. Nutrients. 12(8), 2358. https://doi.org/10.3390/nu12082358. PMID: 32784601; PMCID: PMC7468884.
- Sadeghsoltani, F., Mohammadzadeh, I., Safari, M. M., Hassanpour, P., Izadpanah, M., Qujeq, D., Moein, S., & Vaghari-Tabari, M. (2022). Zinc and Respiratory Viral Infections: Important Trace Element in Anti-viral Response and Immune Regulation. Biol Trace Elem Res. 200(6), 2556-2571. https://doi.org/10.1007/s12011-021-02859-z. PMID: 34368933; PMCID: PMC8349606.
- Shakoor, H., Feehan, J., Al Dhaheri, A. S., Ali, H. I., Platat, C., Ismail, L. C., Apostolopoulos, V., & Stojanovska, L. (2021). Immune-boosting role of vitamins D, C, E, zinc, selenium and omega-3 fatty acids: Could they help against COVID-19?. Maturitas, 143, 1–9. https://doi.org/10.1016/j.maturitas.2020.08.003
- Wessels, I., Rolles, B., & Rink, L. (2020). The Potential Impact of Zinc Supplementation on COVID-19 Pathogenesis. Frontiers in immunology, 11, 1712. https://doi.org/10.3389/fimmu.2020.01712
- Elalfy, H., Besheer, T., El-Mesery, A., El-Gilany, A. H., Soliman, M. A., Alhawarey, A., Alegezy, M., Elhadidy, T., Hewidy, A. A., Zaghloul, H., Neamatallah, M. A. M., Raafat, D., El-Emshaty, W. M., Abo El Kheir, N. Y., & El-Bendary, M. (2021). Effect of a combination of nitazoxanide, ribavirin, and ivermectin plus zinc supplement (MANS.NRIZ study) on the clearance of mild COVID-19. Journal of medical virology, 93(5), 3176–3183. https://doi.org/10.1002/jmv.26880