Micronutrients & recovery
Vitamin D3 supplementation at high doses (10,000 IU/day loading, then 5,000 IU/day maintenance) raises serum 25(OH)D to 40-60 ng/mL, which is associated with a reduced risk of respiratory tract infections including influenza and COVID-19.
If you are at risk for respiratory infections, consider taking 10,000 IU of Vitamin D3 daily for about a month to boost your levels, then switch to 5,000 IU daily. Aim for a blood test showing 40-60 ng/mL of 25(OH)D. Ensure you are also getting enough magnesium, and do not take high-dose calcium supplements simultaneously to avoid toxicity.
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).
Why this rating
The paper is a narrative review citing observational studies and ecological data; it explicitly calls for RCTs to confirm causality.
Source
Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths
William B. Grant et al. · Nutrients · 2020
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