Medicine: Downgrading Vitamin C

Ever since Linus Pauling proposed in 1970 that large doses of vitamin C (ascorbic acid) would prevent or cure the common cold, sales of the vitamin have soared, despite the widely expressed doubts of other researchers. Three reports now cast a further shadow on Pauling’s theory. In one of two studies published in the A.M.A. Journal, 311 volunteers at the National Institutes of Health took part in an experiment in which about half were given one gram of vitamin C three times daily for a nine-month period; the remainder took a placebo under the same circumstances. If a volunteer showed signs of coming down with a cold, the dosage of pills —whether vitamin C or placebo—was increased by three grams per day. N.I.H. researchers report that the effects of the vitamin on the number of colds “seem to be nil” and the effects on severity of the colds are clinically insignificant. In the second Journal report, researchers at the University of Chicago say that after a review of various studies of vitamin C conducted from 1939 to 1973, there is little convincing evidence of the vitamin’s effectiveness in preventing or curing colds. Moreover, they find evidence that large daily doses may even be medically harmful, producing diarrhea or kidney stones.