Vitamin D supplementation is very popular lately. Observational studies suggest an inverse correlation between vitamin D levels and upper respiratory tract infections.Here is a recently published randomized controlled trial testing the association between vitamin D status and upper respiratory tract infection (URTI).
Seven hundred fifty nine participants were randomized to vitamin D3 (1000 IU/day), calcium (1200 mg/day), both, or placebo. Supplementation did not significantly reduce winter episodes of URTI (rate ratio [RR], 0.93; 95% confidence interval [CI], .79-1.09) including colds (RR, 0.93; 95% CI, .78-1.10) or influenza like illness (ILI) (RR, 0.95; 95% CI, .62-1.46), nor did it reduce winter days of illness (RR, 1.13; 95% CI, .90-1.43). There was no significant benefit according to adherence, influenza vaccination, body mass index, or baseline vitamin D status. Semiannual surveys of all participants (N = 2228) identified no benefit of supplementation on ILI (odds ratio [OR], 1.14; 95% CI, .84-1.54) or colds (OR, 1.03; 95% CI, .87-1.23).
Vitamin D supplementation in adults without preexisting vitamin D deficiency may be a cure looking for an (infectious) disease.
