Vitamin C supplementation may have preventive effects in populations with a high incidence of pneumonia, and may have therapeutic effects in populations with low plasma vitamin C levels

Clinical question: 
Does vitamin C have a prophylactic or therapeutic effect in patients with/ at risk of pneumonia?
Bottom line: 
There is no evidence to support widespread prophylactic use of vitamin C to prevent pneumonia in the general population. However, therapeutic vitamin C supplementation may be reasonable for pneumonia patients who have low plasma vitamin C levels because its costs and risks are low.
Caveat: 
Several of the studies reviewed date from many years ago and were conducted in such extraordinary conditions e.g extreme cold that the results may not apply to the general population. There were 37 cases of pneumonia out of 2335 participants.
Context: 
Pneumonia is relatively common, particularly in young children and the aged. It is the most common cause of admission to hospital for adults in some developed countries
Review CD#: 
CD005532
PEARLS No: 
25
Date: 
March, 2007
Authored by: 
Brian R McAvoy