A study published in the American Journal of Clinical Nutrition, September 2007, found a significant relationship between lower levels of Vitamin D and respiratory infections.
The study population was 800 young Finnish men (military conscripts), who were followed over a six-month period. Those with lower blood levels of Vitamin D had about twice as many days out due to respiratory tract infections as their counterparts with higher levels of the vitamin.
NYBC commentary: Still another demonstration of the health benefits associated with Vitamin D. Of course, this was not a study of Vitamin D supplementation, so scientifically speaking, it cannot properly yield a recommendation to take Vitamin D in order to reduce your risk of respiratory infection. But given the strength of this finding, it’s very probable that further investigations on this topic will follow, with the aim of defining any benefit that may come from taking Vitamin D supplements to ward off respiratory tract infections.