Vitamin C in doses as high as one gram daily for several winter months , had no consistent beneficial effect on incidence of the common cold .
For both preventive and therapeutic trials , there was a consistently beneficial but generally modest therapeutic effect on duration of cold symptoms .
There was no clear indication of the relative benefits of different regimes or vitamin C doses .
However in trials that tested vitamin C after cold symptoms occurred , there was some evidence that a large dose produced greater benefits than lower doses .
REVIEW ER 'S CONCLUSIONS Long term daily supplementation with vitamin C in large doses daily does not appear to prevent colds .
BACKGROUND The role of oral ascorbic acid ( vitamin C ) in the prevention and treatment of colds remains controversial despite many controlled trials .
There have also been a number of efforts to synthesize and /or overview the results of these trials , and controversy over what these overviews tell us .
OBJECTIVES The objective of this review was to answer the following two questions : ( 1 ) Does regular high dosage supplementation with vitamin C reduce the incidence of colds ? (
2 ) Does taking vitamin C in high doses at the onset of a cold have a therapeutic effect ?
L-Ascorbic acid and D-isoascorbic acid in a common cold survey.
In a survey of double-bind design , 3 groups of approximately 70 student volunteers took 1 g L-ascorbic acid , 1 g D-isoascorbic acid , or placebo tablets every day for 15 weeks and the incidence and duration of colds were recorded . The group taking D-isoascrobic acid suffered 34 % fewer colds than the other two groups ; the results were also analyzed in relation to the sex and smoking habits of the volunteers . The rationale for investigating D-isoascorbic acid , an isomer of L-ascorbic acid which has limited antiscorbutic activity , is discussed
Vitamin C in doses as high as one gram daily for several winter months , had no consistent beneficial effect on incidence of the common cold .
For both preventive and therapeutic trials , there was a consistently beneficial but generally modest therapeutic effect on duration of cold symptoms .
There was no clear indication of the relative benefits of different regimes or vitamin C doses .
However in trials that tested vitamin C after cold symptoms occurred , there was some evidence that a large dose produced greater benefits than lower doses .
REVIEW ER 'S CONCLUSIONS Long term daily supplementation with vitamin C in large doses daily does not appear to prevent colds .
BACKGROUND The role of oral ascorbic acid ( vitamin C ) in the prevention and treatment of colds remains controversial despite many controlled trials .
There have also been a number of efforts to synthesize and /or overview the results of these trials , and controversy over what these overviews tell us .
OBJECTIVES The objective of this review was to answer the following two questions : ( 1 ) Does regular high dosage supplementation with vitamin C reduce the incidence of colds ? (
2 ) Does taking vitamin C in high doses at the onset of a cold have a therapeutic effect ?