Role of Vitamin D in Risk Reduction of COVID-19: A Narrative Review

• Main Authors: Pinki Mishra, Rizwana Parveen, Nidhi Bharal Agarwal
• Format: Article
• Language: English
• Published: Thieme Medical and Scientific Publishers Pvt. Ltd. 2021-01-01
• Series: Annals of the National Academy of Medical Sciences (India)
• Subjects: covid-19; acute respiratory tract infection; vitamin d; 25-hydroxyvitamin d; sars cov-2
• Online Access: http://www.thieme-connect.de/DOI/DOI?10.1055/s-0041-1724460

The world is in the midst of the COVID-19 pandemic. In addition to quarantine, public health interventions which can reduce the risk of infection and death are urgently required. This article discusses the roles of vitamin D in reducing the risk of COVID-19, and how vitamin D supplementation may be a useful risk reduction measure. Vitamin D can reduce the risk of infections through a variety of mechanisms: induction of cathelicidins and defensins that can lower the rate of viral replication and decrease the concentrations of pro-inflammatory cytokines, which are responsible for induction of inflammation, injuring lining of lungs and contributing to developing pneumonia. Evidence supporting the role of vitamin D in reducing the incidence of COVID-19 includes a) winter outbreak; b) a timeframe when concentrations of 25-hydroxyvitamin D (25(OH)D) are lowest; c) a small number of cases in the southern hemisphere toward the end of summer; d) a vitamin D deficiency found to lead to acute respiratory distress syndrome (ARDS); e) and a rise in case-fatality rates with increasing age and comorbid chronic diseases, both of which are associated with lower concentrations of 25(OH)D. It is recommended that people at risk of COVID-19 consider taking 10,000 IU/d of vitamin D3 for a few weeks to rapidly increase 25(OH)D concentrations, followed by 5,000 IU/d to reduce the risk of infection. Higher doses of vitamin D3 may be useful for treating people who are infected with COVID-19. To test these guidelines, randomized controlled trials and comprehensive population studies should be performed.