New research shows that people with the lowest vitamin D blood levels are about one-third more likely to catch an upper respiratory tract infection (cold) than those with the highest levels (the “high” vitamin D group, however was nowhere near optimal levels). This study is no surprise, considering the research that I posted earlier on this blog regarding colds and flu. There is something that makes this research different, however. Among asthmatics, the risk of catching cold was 5.7 times higher in the people with the lowest levels of vitamin D.
One of my previous posts already discussed the profound correlation of low vitamin D levels to asthma. With all of the suffering asthmatics must go through, an upper respiratory tract infection is not something that needs to be added to it. The evidence indicates that the risk of both asthma and colds can be reduced substantially by maintaining high levels of vitamin D. Act accordingly!
 Ginde, A. et al. Association Between Serum 25-Hydroxyvitamin D Level and Upper Respiratory Tract Infection in the Third National Health and Nutrition Examination Survey ARCH INTERN MED;169:4:384-90.