Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths.

Nutrients. 2020;12(4)
Full text from:

Plain language summary

This narrative review article looks at the role of Vitamin D in reducing the risk of respiratory tract infections, in relation to the incidence and prevalence of influenza and COVID-19. It also discusses how Vitamin D testing and optimisation with supplementation might be a simple measure to reduce risk. The authors site evidence supporting the possible role of Vitamin D: the fact that the outbreak occurred in winter when Vitamin D concentrations are lowest; vitamin D deficiency has been shown to contribute to acute respiratory distress; and case fatality rates increasing with age and incidence of underlying conditions, both of which are associated with lower Vitamin D concentrations. The authors goal is to raise Vitamin D concentrations to 100-150 nmol/l. Nutrition Practitioners wanting to support overall health and resilience to seasonal viral infections may want to consider testing and supplementing Vitamin D.

Abstract

The world is in the grip of the COVID-19 pandemic. Public health measures that can reduce the risk of infection and death in addition to quarantines are desperately needed. This article reviews the roles of vitamin D in reducing the risk of respiratory tract infections, knowledge about the epidemiology of influenza and COVID-19, and how vitamin D supplementation might be a useful measure to reduce risk. Through several mechanisms, vitamin D can reduce risk of infections. Those mechanisms include inducing cathelicidins and defensins that can lower viral replication rates and reducing concentrations of pro-inflammatory cytokines that produce the inflammation that injures the lining of the lungs, leading to pneumonia, as well as increasing concentrations of anti-inflammatory cytokines. Several observational studies and clinical trials reported that vitamin D supplementation reduced the risk of influenza, whereas others did not. Evidence supporting the role of vitamin D in reducing risk of COVID-19 includes that the outbreak occurred in winter, a time when 25-hydroxyvitamin D (25(OH)D) concentrations are lowest; that the number of cases in the Southern Hemisphere near the end of summer are low; that vitamin D deficiency has been found to contribute to acute respiratory distress syndrome; and that case-fatality rates increase with age and with chronic disease comorbidity, both of which are associated with lower 25(OH)D concentration. To reduce the risk of infection, it is recommended that people at risk of influenza and/or COVID-19 consider taking 10,000 IU/d of vitamin D3 for a few weeks to rapidly raise 25(OH)D concentrations, followed by 5000 IU/d. The goal should be to raise 25(OH)D concentrations above 40-60 ng/mL (100-150 nmol/L). For treatment of people who become infected with COVID-19, higher vitamin D3 doses might be useful. Randomized controlled trials and large population studies should be conducted to evaluate these recommendations.

Lifestyle medicine

Fundamental Clinical Imbalances : Hormonal ; Immune and inflammation
Patient Centred Factors : Mediators/Vitamin D/viral infections
Environmental Inputs : Nutrients
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Not applicable
Bioactive Substances : Vitamin D

Methodological quality

Allocation concealment : Not applicable
Publication Type : Journal Article ; Review

Metadata