Think immune supplement, think vitamin C – especially for the common cold.
There have been some questions raised about the efficacy of the vitamin to reduce the incidence of the common cold, with a review of 30 studies published in The Cochrane Library concluding that daily doses of at least 200 milligrams did little to reduce the length or severity of a cold.
However, the review also found that daily supplements of vitamin C may reduce the risk of developing common cold for marathon runners by 50% at a dose of 0.2 grams per day.
Select analysis further revealed that vitamin C supplements did reduce the duration of common colds in adult and children by 8% and 14%, respectively.
In addition, a dose of 1 to 2 grams per day reduced the duration by 18% for children.
Source: Hemila et al. The Cochrane Library. 2013.“Vitamin C for preventing and treating the common cold”