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The common cold is a leading cause of doctor visits and results in school or work absenteeism. The economic losses associated with it are comparable to hypertension and stroke. Previous randomized studies have indicated that vitamin C may reduce the duration and severity of colds. However, there is a persistent widespread belief that this supplement provides no benefits. According to researchers, this belief is based on several flawed reviews and the analysis of one particularly influential study.
About the Study
In a review conducted by researchers from the University of Helsinki and the Australian National University, the impact of vitamin C on both severe and mild cold symptoms is systematically compared. The meta-analysis included 15 comparisons between vitamin C and a placebo from 10 randomized trials. Most of these trials lasted from two to five months, except for two conducted over one week.
All included studies were placebo-controlled. Individuals with good health at the onset of a cold took at least 1 gram of vitamin C orally per day, with a maximum dose not exceeding 4 grams per day.
How Does Vitamin C Affect the Course of a Cold?
The results of the meta-analysis indicate that vitamin C supplements reduce the number of days absent from work and school as well as the duration of staying at home by 15%. The groups receiving the supplement also demonstrated a 13% reduction in the severity of the cold.
The analysis also revealed a 26% reduction in the duration of severe symptoms compared to the absence of a significant impact of the vitamin on mild symptoms. There were some indications that the influence may be stronger for men than for women.
Scientific Conclusions
The authors believe that their findings strengthen and expand existing evidence of the effectiveness of vitamin C in reducing symptoms of the common cold.
Future research may focus on the role of therapeutic consumption of the vitamin after the onset of initial symptoms. However, according to the researchers, even now, vitamin C supplements can be a safe, accessible, and effective means of protection against the common cold.
It is worth noting that a recent study found that excessive physical exertion increases the risk of catching a cold.
