Will vitamin C cure the common cold?

Dear Cecil: I haven’t heard much about Linus Pauling’s theories on vitamin C as a cure for the common cold lately, although I know several people who continue to down their C capsules religiously. Has any evidence been found to prove or disprove Pauling’s claims? The whole business is beginning to look like a fad that has peaked. You have a fine skeptical mind, Cecil, so I know I can trust you to provide an unbiased opinion. Kathy M., Los Angeles

Cecil replies:

I don’t claim to be unbiased, Kathy. However, my prejudices are amazingly well-informed. Far from being a fad, what’s commonly known as megavitamin therapy has become a mighty industry. Working on the theory that if a little is good for you, a lot is better, health food stores and the like now hawk all manner of vitamins and dietary supplements, some more dubious than others. For example, vitamins A and D, when taken in the massive doses prescribed by megavitamin therapy, are stored in your body fat and can easily build to poisonous levels. OD on the A and you can get “hypervitaminosis A,” with symptoms that strongly resemble a brain tumor. That won’t happen with vitamin C, which dissolves in the body’s water and passes out through the usual routes. On the other hand, it’s not clear you’ll be doing yourself any good.

Despite a good deal of research since Linus Pauling made his original claims in 1971, there’s still no conclusive evidence that vitamin C can prevent, cure, or alleviate colds. Some studies have shown a benefit, but most researchers attribute that to the placebo effect — if you think a pill will help you, it will, even though the therapeutic activity is occurring strictly between your ears. Much of the recent research on colds has centered on their psychosomatic side: emotional problems, such as nerves, stress, and depression, appear to play as large a part in bringing on colds as do the elusive germs. By helping you get a grip, C may help you feel better, even though strictly speaking it has no medical value.

But vitamin C fans aren’t ready to give up yet. A scientist from Finland, H. Hemila, has published a flurry of articles in the medical journals in recent years claiming that the anti-C crowd has misrepresented the data and that vitamin C really does work. Even Hemila doesn’t claim it does miracles. In a 1997 review of six major studies in the British Journal of Nutrition, Dr. H. concedes there is “no evidence that high-dose vitamin C supplementation decreases common cold incidence in ordinary people.” But it may help folks who don’t get enough C in their ordinary diet — British male schoolchildren and students, for example. If you’re the type who doesn’t eat your vegetables, I suppose you might want to give megadoses of C a try. But I bet you could do yourself just as much good eating right.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.