VITAMIN-C AND THE COMMON COLD - A RETROSPECTIVE ANALYSIS OF CHALMERS REVIEW

In 1975 Thomas Chalmers analyzed the possible effect of vitamin C on t he common cold by calculating the average difference in the duration o f cold episodes in vitamin C and control groups in seven placebo-contr olled studies. He found that episodes were O.11 +/- 0.24 (SE) days sho rter in the vitamin C groups and concluded that there was no valid evi dence to indicate that vitamin C is beneficial in the treatment of the common cold. Chalmers' review has been extensively cited in scientifi c articles and monographs. However, other reviewers have concluded tha t vitamin C significantly alleviates the symptoms of the common cold. A careful analysis of Chalmers' review reveals serious shortcomings. F or example, Chalmers did not consider the amount of vitamin C used in the studies and included in his meta-analysis was a study in which onl y 0.025-0.05 g/day of vitamin C was administered to the test subjects. For some studies Chalmers used values that are inconsistent with the original published results. Using data from the same studies, we calcu lated that vitamin C (1-6 g/day) decreased the duration of the cold ep isodes by 0.93 +/- 0.22 (SE) days; the relative decrease in the episod e duration was 21%. The current notion that vitamin C has no effect on the common cold seems to be based in large part on a faulty review wr itten two decades ago.