Vitamin C for preventing and treating the common cold

Hemila H, Chalker E

Published in Cochrane Database of Systematic Reviews

Methodology

Cochrane review of randomized trials of regular vitamin C supplementation for prevention and treatment of the common cold.

Key Findings

Regular vitamin C did not reduce cold incidence in the general population but shortened duration modestly and halved incidence in people under extreme physical stress.

Conclusions

Vitamin C offers limited pathogen resistance benefit outside high-stress groups.

Limitations

Cold incidence unaffected in ordinary adults; heterogeneous dosing.

Supplements Studied

Vitamin C

Vitamin

Regular vitamin C did not reduce cold incidence in the general population but shortened duration modestly

Outcomes Measured

Pathogen Resistance

Regular vitamin C did not reduce cold incidence in the general population but shortened duration modestly

Immune Function

Regular vitamin C supplementation reduced common cold duration in the general population.

Bacterial Infection Prevention

Regular vitamin C supplementation did not reduce common cold incidence in the general population.

Cold Prevention

Primary

The failure of vitamin C supplementation to reduce the incidence of colds in the general population indicates that routine vitamin C supplementation is not justified, yet vitamin C may be useful for people exposed to brief periods of severe physical exercise.