Linus Pauling: Nobel Prize Scientist

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PLOWBOY: Is it your contention that no studies have been done which disprove the idea that vitamin C helps prevent colds? Do no such studies exist?

PAULING: I discussed all of the controlled trials I could find in the literature in my last book, Vitamin C, the Common Cold, and the Flu. There were 14 controlled trials altogether. All involved two groups of subjects — a " vitamin C " group and a "placebo" group — and none of the subjects of either group knew whether he or she was receiving ascorbic acid tablets, or tablets of a harmless but indistinguishable placebo, such as citric acid. And every one of these 14 studies showed some protective effect by vitamin C greater than the placebo. That's not to say that they all got the same result: For one thing, the various investigators used different amounts of vitamin C, so you wouldn't expect all the studies to show the same amount of protective effect. Even those that used the same amount of ascorbic acid got different results ... because they were studying different populations under different conditions. But the main thing is, every study showed some protective effect of vitamin C against colds ... even those in which the investigators said they didn't get a protective effect.

PLOWBOY: Wait a minute ... you mean some investigators drew the wrong conclusion from their own results?

PAULING: That's right.

PLOWBOY: Can you give me an example?

PAULING: Well for instance in 1942, Cowan, Diehl, and Baker of the University of Minnesota published a report in the Journal of the American Medical Association. In it, they described the results of a controlled, double-blind study in which they found that persons who received 200 milligrams of vitamin C per day experienced 31% less illness than the persons in a control group who got a placebo. But in the summary of their paper — which is the only part that would be read by most of the people who read the Journal of the American Medical Association anyway — Cowan, Diehl, and Baker say: "This controlled study yields no indication that large doses of vitamin C have any important effect on the number or severity of infections of the upper respiratory tract." They didn't say that they had observed this 31% decrease in the amount of illness in one group ... they apparently didn't consider this effect to be important, even though the numbers do have statistical significance. They couldn't say "showed no effect", of course, because that would have been false. Instead, they said "no important effect".

This statement in the summary of the paper by Cowan, Diehl, and Baker has become the basis for a lot of misinformation. Because if you look in one of the standard medical texts, it says "Cowan, Diehl, and Baker found in 1942 that massive doses of vitamin C have no effect on the incidence of colds." The authors of the book, in other words, have left out the word "important" . . . and of course by doing this, they've misrepresented the work of Cowan, Diehl, and Baker, who — as I have said — have misrepresented their own work to a certain extent.

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