Vitamin C
I have just the thing for that cold … Vitamin C
Claiming vitamin C is useless for colds is enough to get one beaten up in some circles. If Aaron did not have ninja skills, we would never get out of auditoriums alive when we dispel this myth. Vitamin C is on every health food and pharmacy shelf, and people take it both to prevent colds and to treat them. Just because many people use something faithfully and swear by it does not mean that it works.
Tests of whether vitamin C prevents colds have been done on thousands of people. The research investigating vitamin C is impressive. When scientists combine the results of twenty-three studies investigating whether vitamin C prevents colds in normal people, there is no significant improvement. Vitamin C does not prevent you from getting a cold. In studies involving over 11,000 people taking 200 mg or more of vitamin C a day, the vitamin C did not prevent colds. In a subset of people studied, vitamin C came a little closer to looking like it would work (although the results were still statistically insignificant). In people who engaged in extreme exercise in extreme conditions—marathon runners, soldiers training in the Arctic, and skiers—vitamin C almost looked like it worked to prevent colds. But it still made no significant difference. If you plan on engaging in seriously strenuous exercise in very cold conditions, you might consider taking a vitamin C supplement in the hope that it just might work, but otherwise there is no evidence to justify taking regular doses.
Sadly, vitamin C does not kill the viruses that cause colds, nor does it seem to make your cold symptoms better. In seven studies looking at the treatment of the common cold, scientists found no improvement in symptoms if you took vitamin C. It was no better than a placebo; neither one improved the cold symptoms. Based on the results of eleven studies of more than 6,000 people, taking vitamin C does not make the duration of your cold any shorter or your cold any less severe. In these trials, people took doses up to 4 grams (4,000 mg) and did not see a benefit in cold symptoms. Vitamin C doesn’t work!