Vitamin D as a Preventive or Therapeutic Nutrient in COVID-19 Infection

Abstract

SARS-CoV-2 has caused a global pandemic with limited treatment options available. Some studies have proposed that vitamin D may be associated with Covid-19 infection outcomes. The aim of this literature review is to analyze the evidence currently available from Randomized Controlled Trials (RCTs) and quasi-experimental studies regarding the impact of vitamin D used as a preventative or adjunctive therapeutic agent on the disease severity and mortality rate of Covid-19 patients. A literature search was performed using PubMed, Science Direct, and ProQuest. Sources listed in the citations of systematic reviews and meta-analyses were also evaluated. Articles meeting the inclusion criteria were selected after title, abstract, and article content were reviewed. Five studies, including two RCTs, met inclusion criteria. One RCT did not find significant benefit with vitamin D3 supplementation. The remaining studies, including mostly elderly participants using various vitamin D supplementation forms and doses, reported a reduced need for ICU treatment, faster recovery, decreased severity, and an improved survival rate for Covid-19 patients. An initial loading dose (21,280 IU Calcifediol) and regular supplementation of vitamin D (10,000-60,000 IU/day when ill to monthly doses of 50,000 IU or 80,000-100,000 IU/2-3 months) resulted in the greatest effectiveness. The results of this review suggest that regular vitamin D supplementation may be associated with reduced Covid-19 infection severity and mortality rate. However, more RCTs are needed to provide further robust evidence for more participants of different demographics and give insight into the most appropriate doses, forms, and timeline of vitamin D supplementation for patients with SARS-CoV-2. Keywords: Vitamin D3; Calcifediol; Randomized controlled trials; Recovery rate; Survival rate