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 ?
Common cold symptomatology and Vitamin C
Summary The occurrence and severity of nine symptoms of the common cold were recorded daily for 35 weeks by girls and boys in four Dublin boarding schools . Half the children in each school received placebo or 200 mg tablets , or 200 mg or 500 mg tablets , of Vitamin C daily on a double blind basis . Diets or environmental conditions did not differ between the schools . A score for the severity of each symptom was obtained daily for all the subjects throughout the trial in the different treatment groups . The degree of association between pairs of symptoms was calculated . The symptoms of the common cold syndrome ( the W-complex ) tended to exist in two groups defined as Toxic and Catarrhal complexes ( T- and C-complexes ) . The intensity and quality of W-complex symptoms were assessed in terms of the correlation value above which the constituent T- and C-complexes became manifest , the average correlation values of the constituent complexes , and the linkage of the symptoms in these complexes . The values for , and quality of , the complexes were dependent on the sex of the sample s and the dose of Vitamin C administered . Boys tended to have more complicated W-complexes which broke down into T- and C-complexes with the lower dose of Vitamin C. These became more complicated when increasing doses of Vitamin C were administered . Girls had less complicated W-complexes , but more complicated T- and C-complexes , than boys . Increasing doses of Vitamin C made the girls ' T- and C-complexes less complicated . Administration of Vitamin C appeared to benefit the common cold syndrome more in girls than in boys
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 ?