Dietary Supplements for COVID-19

This is a double blind, placebo controlled, phase III randomized controlled trial evaluating the effects of the dietary supplements vitamin C, vitamin D, vitamin K, and zinc versus placebo on the overall health, symptom severity, and symptom duration of outpatients diagnosed with SARS-CoV-2.

This study proposed is a double-blind, placebo-controlled, phase III randomized controlled trial powered to detect meaningful differences in the overall health and symptom severity of people with COVID-19 between the treatment and control arms. Eligible participants will be randomly assigned, using a web randomization system, in a ratio of 1:1 to one of the following groups: (1) nutrient therapy with vitamin D, vitamin C, vitamin K2, and zinc or (2) placebo. Total trial duration will be 12 weeks. Nutrients or placebo will be given for a period of 21 days following enrolment and randomization. Total trial duration will be 12 weeks. Adverse events will be collected during the treatment phase plus one additional week (maximum 4 weeks). With respect to the primary outcome of participant-reported overall health, power calculations were conducted based on between-group differences at a single time point (21 days) and Cohen's guideline for a small effect size of 0.3. A sample size of 176 (88 per arm) provides 80% power to detect a difference at an α of 0.05. To account for an approximate 10-15% lost to follow-up we will enrol 200 participants (100 per arm).