Feb. 13, 2013 According to an updated Cochrane Review on vitamin
C and the common cold, vitamin C seems to be particularly
beneficial for people under heavy physical stress. In five
randomized trials of participants with heavy short-term physical
stress, vitamin C halved the incidence of the common cold. Three
of the trials studied marathon runners, one studied Swiss school
children in a skiing camp and one studied Canadian soldiers
during a winter exercise. Furthermore, in a recent randomized
trial carried out with adolescent competitive swimmers, vitamin
C halved the duration of colds in males, although the vitamin
had no effect on females. Regular doses of vitamin C of one gram
per day or higher have reduced the average duration of colds in
adults by 8% and in children by 18%. Although these findings
unambiguously show that vitamin C has a biological effect on
colds, taking vitamin C every day to shorten infrequent colds
does not seem reasonable. On average, adults have only a few
common cold episodes per