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 randomized controlled trial of the therapeutic effect of vitamin C in the common cold.
METHOD A large number of women living in two towns in South Wales , and their husb and s , were asked to cooperate in the trial . These women had been identified several years previously in a study of child growth and nutrition and had already cooperated in a prophylactic trial of vitamin C ( Elwood et al. , 1975 ) . The subjects were visited in September and October and those who agreed were given ten effervescent tablets of either vitamin C ( 1 G ) or an inert ; placebo . Allocation of households to vitamin C or placebo was r and om , but each husb and received the same tablets as his wife . This was done to avoid confusion if tablets were shared . The smoking habit of each subject was recorded . Instructions were given that , when symptoms suggestive of a cold commenced , the tablets were to be started , three tablets per day until the 10 tablets had been taken . Symptoms were to be recorded each day for the duration of the cold . Sufficient detail was requested to enable colds to be classed as ‘ simple ’ , that is nasal symptoms with or without general symptoms such as fever or malaise but without any symptom referable to the chest such as cough . ‘ Chest ’ colds were recorded as any symptom-complex which included cough , wheezing , or other chest symptoms . A stamped addressed envelope was given to each subject for the return of the record card . An arbitrary date was chosen approximately six months after the trial commenced , and any subject who had not returned a
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 ?