Upper respiratory tract infection vitamin

Vitamin C status is supposed to play a role in immune function and to influence the progression of some chronic degenerative diseases like atherosclerosis, cancer, cataracts, and osteoporosis. The role of vitamin C in immune function, especially during common cold and upper respiratory tract infection, is the subject of lively debate. The exact mechanisms of action have not yet been fully elucidated, but the results of several trials point to a reduced duration and intensity of infections in subjects consuming high amounts of vitamin C (200-1000 mg/d). However, the incidence of common cold was not influenced significantly (24). 

Peters, E. M., Goetzsche, J. M., Grobbelaar, B., and Noakes, T. D., 1993, Vitamin C supplementation reduces the incidence of postrace symptoms of upper-respiratory-tract infection in ultramarathon mnners, Am. J. Clin. Nutr. 57 170-174. 

Another randomized controlled trial of vitamin D supplementation was undertaken in 162 adult subjects with a biweekly questionnaire to record symptoms of upper respiratory tract infections. While dosing with 2000 lU vitamin D daily in the treated group increased circulating 25(OH)D values, no differences in respiratory tract symptoms or their severity were noted relative to controls (Li-Ng et al. 2009). 

Li-Ng, M., Aloia, J. R, Pollack, S. et al. 2009. A randomized controlled trial of vitamin D3 supplementation for the prevention of symptomatic upper respiratory tract infections. Epidemiol Infect 137 1396-404. 

Placebo-controlled studies The efficacy and safety of high-dose vitamin C (4 g/day) in the treatment of type 1 Charcot-Marie-Tooth disease has been evaluated in a randomised, double-blind, placebo-controlled study including 110 participants aged between 13 and 17years. The most frequently observed adverse events included heartburn, vomiting, reflux and upper respiratory tract infections. There were 18 serious adverse events, but none was related to the study drug [32 j. 

Among children in Africa, the Middle East, and Asia, vitamin D status appears to influence the risk of developing both upper and lower respiratory tract infections. A thirteen-fold higher risk of pneumonia was found in vitamin D-deficient Ethiopian children less than five years of age compared to vitamin D-sufficient age-matched... 

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