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 ?
A co-twin control study of the effects of vitamin C.
In recent years , a number of benefits of prophylactic pharmacologic doses of vitamin C have been suggested . In addition to cl aims by Linus Pauling [ 1971 ] and others of a reduction in the morbidity due to the common cold and upper respiratory infections , other authors have subsequently suggested that serum cholesterol levels may be lowered [ Spittle , 1971 ] . Some investigations have suggested that this effect may be observed only in hypercholesterolemic individuals and not those with normal cholesterol levels [ Sokoloff et al , 1966 ; Ginter et al , 1970 ] . It has also been suggested that exogenous vitamin C might improve mental alertness as measured by IQ test performance [ Kubala and Katz , 1960 ] . The present study was design ed to test these hypotheses by means of a double-blind co-twin control study
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 ?