Due to the small number of included studies and very low quality of the existing evidence , we are uncertain of the effect of vitamin C supplementation for the prevention and treatment of pneumonia .
BACKGROUND According to the Global Burden of Disease Study 2015 , lower respiratory tract infection is the leading cause of infectious disease death , and the fifth most common cause of death overall .
Vitamin C has a role in modulating resistance to infectious agents , therefore vitamin C supplementation may be important in preventing and treating pneumonia .
OBJECTIVES To assess the impact of vitamin C supplementation to prevent and treat pneumonia in children and adults .
Vitamin C prophylaxis in marine recruits.
A prospect i ve , r and omized , double-blind study was carried out to determine whether vitamin C prophylaxis , 2.0 g/day , vs placebo prophylaxis would reduce the incidence or morbidity of the common cold  and other respiratory illnesses in 674 marine recruits during an eight-week period . Whole-blood ascorbic acid levels measured six weeks after initiation of the study were significantly higher in the vitamin C group . There was no difference between the two groups in the incidence or duration of colds . The vitamin C group rated their colds as being less severe , but this was not reflected in different symptom complexes or in fewer sick-call visits or training days lost . This study and the literature do not support the prophylactic use of vitamin C to prevent the common cold
Due to the small number of included studies and very low quality of the existing evidence , we are uncertain of the effect of vitamin C supplementation for the prevention and treatment of pneumonia .
BACKGROUND According to the Global Burden of Disease Study 2015 , lower respiratory tract infection is the leading cause of infectious disease death , and the fifth most common cause of death overall .
Vitamin C has a role in modulating resistance to infectious agents , therefore vitamin C supplementation may be important in preventing and treating pneumonia .
OBJECTIVES To assess the impact of vitamin C supplementation to prevent and treat pneumonia in children and adults .