Hemilä H, Herman Z S
Department of Public Health, University of Helsinki, Finland.
J Am Coll Nutr. 1995 Apr;14(2):116-23. doi: 10.1080/07315724.1995.10718483.
In 1975 Thomas Chalmers analyzed the possible effect of vitamin C on the common cold by calculating the average difference in the duration of cold episodes in vitamin C and control groups in seven placebo-controlled studies. He found that episodes were 0.11 +/- 0.24 (SE) days shorter in the vitamin C groups and concluded that there was no valid evidence to indicate that vitamin C is beneficial in the treatment of the common cold. Chalmers' review has been extensively cited in scientific articles and monographs. However, other reviewers have concluded that vitamin C significantly alleviates the symptoms of the common cold. A careful analysis of Chalmers' review reveals serious shortcomings. For 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 only 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 calculated that vitamin C (1-6 g/day) decreased the duration of the cold episodes by 0.93 +/- 0.22 (SE) days; the relative decrease in the episode 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 written two decades ago.
1975年，托马斯·查尔默斯通过计算7项安慰剂对照研究中维生素C组和对照组感冒发作持续时间的平均差异，分析了维生素C对普通感冒可能产生的影响。他发现维生素C组的发作时间缩短了0.11±0.24（标准误）天，并得出结论，没有有效证据表明维生素C对治疗普通感冒有益。查尔默斯的综述在科学文章和专著中被广泛引用。然而，其他综述作者得出结论，维生素C能显著减轻普通感冒的症状。对查尔默斯综述的仔细分析揭示了严重的缺陷。例如，查尔默斯没有考虑研究中使用的维生素C的量，并且他的荟萃分析中纳入了一项仅给试验对象服用0.025 - 0.05克/天维生素C的研究。对于一些研究，查尔默斯使用的值与最初发表的结果不一致。利用相同研究的数据，我们计算得出维生素C（1 - 6克/天）可使感冒发作持续时间缩短0.93±0.22（标准误）天；发作持续时间的相对缩短为21%。目前认为维生素C对普通感冒没有影响的观点似乎在很大程度上是基于20年前一篇有缺陷的综述。
