Common cold, ascorbic acid effects

The long-standing interest in the properties of L-ascorbic acid is manifested by the fact that 1146 references related to vitamin C are listed for year 2000 in the PUB MED index in the Internet. The most popular use of L-ascorbic acid is for prevention and treatment of the common cold, but this role remains controversial. In a recent review, the authors conclude that the long-term daily supplementation with large doses of vitamin C does not appear to prevent colds, but there is a modest therapeutic effect on the duration of cold symptoms.369... 

Chalmers TC (1975) Effects of ascorbic acid on the common cold. An evaluation of the evidence. American Journal of Medicine 58, 532-6. 

In spite of the lack of nneqnivocal evidence of a beneficial effect of large doses of ascorbic acid for preventing or treating the common cold, the nse of ascorbic acid for this indication is still widespread. 

Vitamin C (ascorbic acid), besides its other purposes — for example, in preventing scurvy — is a suspected antiviral agent, though the point is controversial and not settled. In other words, the effectiveness of vitamin C as a cure or preventive for the common cold is still argued (see the woik of Linus Pauling), though recognition has come about that vitamin C at least alleviates its symptoms (Chaney, in Devlin, 1986, p. 1227). To which may be added, that the common cold is caused by a virus, and if vitamin C is not always effective, neither is the immune system, or we would never get sick in the first place. 

Linus Pauling often suffered from bad colds, so he was quite receptive to the advice of one of his biochemist friends, who proposed consuming several grams of ascorbic acid to prevent the common cold. Pauling found the method effective and... 

The level of confidence at which the null hypothesis that ascorbic acid has no more effect than a placebo is rejected by the observations of Cowan, Diehl, and Baker in their carefully controlled study is given by P (one-tailed) less than 0.01 that is, on the basis of this study ascorbic acid is shown to be effective in decreasing the integrated morbidity of the common cold at the 99% confidence level. 

Several other carefully controlled studies of ascorbic acid and the common cold have been carried out under similar circumstances, and have yielded results with statistical significance. The amount of protective effect that has been reported is approximately the same as that found in the two studies discussed above. 

The side effects of high doses of ascorbic acid have been reviewed in connection with the use of vitamin C in patients with the common cold (26 ) the principal problems in this connection were dealt with in SED Vlll. Investigations in pastoral Aibes in Kenya with a high cholesterol intake revealed a positive correlation between levels of serum cholesterol and both plasma and leukocyte ascorbate (27 ). 

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