RT Journal
A1 Ginde AA, Mansbach JM, Camargo CA, Jr
T1 VItamin d level, respiratory tract infections, and controlled trials—reply
JF Archives of Internal Medicine
JO Archives of Internal Medicine
YR 2009
FD August 10
VO 169
IS 15
SP 1443
OP 1444
DO 10.1001/archinternmed.2009.247
UL http://dx.doi.org/10.1001/archinternmed.2009.247
AB 
We thank Dr Hemilä for this correspondence. The Cochrane review by Douglas et al1 supported our statement that vitamin C has a limited role in prevention and treatment of colds and concluded that the prophylactic or therapeutic use of vitamin C does not reduce the incidence or severity of colds. There was a modest reduction (approximately 12 hours) in duration of colds with prophylactic but not therapeutic use of vitamin C, but as those authors conclude, “there seems no justification for routine mega-dose vitamin C supplementation in the normal population” and “therapeutic supplementation has not been shown to be beneficial.”1