Throughout the world, there are countless ways used to combat the common cold. Vitamins, herbal treatment, teas and soups are all methods that come to mind. As winter arrives, we took a look at literature reviews to see what the scientific support was for 3 of the most common remedies. The selected literature reviews were produced by Cochrane Reviews, which are internationally recognized as a standard in evidence-based health care resources.
Among the 29 trials and 11,306 participants examined, this review found that routine vitamin C supplementation does not reduce the incidence of colds in the general population. For athletes undergoing intense physical training (e.g. marathon runners, skiers), however, those supplemented with vitamin C were only 48% as likely to get a cold as athletes not supplemented with vitamin C. You can read about the link between intense physical activity and immunity in our blog Why Don’t Athletes Shake Hands in the Olympic Village.
There is some evidence that vitamin C can reduce the duration of colds, but these results weren’t able to be replicated in therapeutic trials.
This review, which examined 18 trials, found that zinc supplementation led to shorter cold duration by approximately one day. Participants taking zinc were 45% as likely to be symptomatic after 7 days than those not taking zinc. However, the variety in design of studies examined means these average estimates should be viewed with caution, according to the authors. It was also common for those taking zinc to report adverse affects, such as nausea or bad taste. The authors recommend supplementation of zinc at ≥75 mg/day for the duration of colds.
Echinacea plant is widely used in several countries as a treatment for common colds. However, this review found that there was no evidence to show Echinacea provides benefits for treating colds and participants taking Echinacea during trials often reported adverse events.