Influence of Vitamin D Supplementation by Simulated Sunlight or Oral D3 on Respiratory Infection During Military Training

Sophie E. Harrison; Samuel J. Oliver; Daniel S. Kashi; Alexander T. Carswell; Jason P. Edwards; Laurel M. Wentz; Ross Roberts; Jonathan C. Y. Tang; Rachel M. Izard; Sarah Jackson; Donald Allan; Lesley E. Rhodes; William D. Fraser; Julie P. Greeves; Neil P. Walsh


Med Sci Sports Exerc. 2021;53(7):1505-1516. 

In This Article


Vitamin D sufficiency reduced URTI burden in military recruits during arduous training. In study 1, vitamin D–sufficient recruits were less likely to have a URTI compared with those with serum 25(OH)D <50 nmol·L−1. In study 2, winter vitamin D supplementation, which achieved vitamin D sufficiency in almost all (≥95%), reduced peak URTI severity and total days with URTI compared with placebo. To reduce the burden of URTI, maintaining vitamin D sufficiency is recommended for military personnel and other active populations, such as athletes who participate in arduous training.