Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths
Grant et al.,
Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths,
Nutrients, 12:4, 988, doi:10.3390/nu12040988 (Review)
Review of the evidence that vitamin D supplementation could reduce COVID-19 risk.
Grant et al., 2 Apr 2020, peer-reviewed, 7 authors.
Abstract: nutrients
Review
Evidence that Vitamin D Supplementation Could
Reduce Risk of Influenza and COVID-19 Infections
and Deaths
William B. Grant 1, * , Henry Lahore 2 , Sharon L. McDonnell 3 , Carole A. Baggerly 3 ,
Christine B. French 3 , Jennifer L. Aliano 3 and Harjit P. Bhattoa 4
1
2
3
4
*
Sunlight, Nutrition, and Health Research Center, P.O. Box 641603, San Francisco, CA 94164-1603, USA
2289 Highland Loop, Port Townsend, WA 98368, USA; hlahore@vitamindwiki.com.
GrassrootsHealth, Encinitas, CA 92024, USA; Sharon@grassrootshealth.org (S.L.M.);
carole@grassrootshealth.org (C.A.B.); Christine@grassrootshealth.org (C.B.F.);
jen@grassrootshealth.org (J.L.A.)
Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Nagyerdei Blvd 98,
H-4032 Debrecen, Hungary; harjit@med.unideb.hu
Correspondence: wbgrant@infionline.net; Tel.: +1-415-409-1980
Received: 12 March 2020; Accepted: 31 March 2020; Published: 2 April 2020
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.
Keywords: acute respiratory distress syndrome (ARDS); ascorbic acid; cathelicidin; coronavirus;
COVID-19; cytokine storm; influenza; observational; pneumonia; prevention; respiratory tract
infection; solar radiation; treatment; UVB; vitamin C; vitamin D
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