But careful examination of the second Mayo clinic study shows that Pauling's hypothesis was never tested. Pauling said that terminal cancer patients fed vitamin C until death would live substantially longer. In the Mayo study, as soon as the cancer progressed, patients were taken off vitamin C. The researchers claimed that it was unethical to keep them on the therapy because it wasn't working. In fact, there was no way to know whether the vitamin C was "working" unless patients were kept on it until they died. Keep in mind that these were terminal patients to begin with. Pauling and Cameron had never said that the vitamin was curative (though a couple of their patients actually lived for many years); rather, they claimed only that terminal patients taking C until they died lived longer on average.

There was another irony in the stance taken by the Mayo Clinic team While it was "inhumane" to keep patients on vitamin C an inexpensive and harmless supplement, many of these patients were subsequently given fluorouracil, the very form of chemotherapy that had been proven repeatedly to be ineffectual and toxic in the treatment of colon cancer. Recall that the uselessness of chemo was the initial ethical justification for putting terminal colon cancer patients on a regimen that did not include chemo. Although the transparency of the clinic researchers' bias has been discussed in relatively obscure alternative sources,56 it has not been picked journals.

A separate criticism of the second Mayo Clinic trial also has some merit: The control group may also have been taking vitamin C. All of the colon cancer patients were told that vitamin C was being tested to see if it would help them. They were also told that they might not be getting the real vitamin C; their pill might be just a placebo. Under these circumstances, who would be so compliant as to not sneak a little vitamin C on the side? Such a surreptitious change would obviously invalidate the outcome. A very limited investigation was made to rule out this possibility (only six placebo-taking patients were checked, and they were checked at only one point in time). Vitamin C excreted in urine reflects oral intake; patients were considered not to be taking clandestine vitamin C if their urine contained 550 milligrams of vitamin C per day or less--vastly more than the average person will excrete under normal circumstances. It seems inconceivable that the Mayo researchers didn't know that fact. Even at the 550 milligram level, one of the six patients exceeded the limit, strongly suggesting that he or she was "cheating," as most thinking people would do under the circumstances. To restate the implications, patients in the placebo group could have been taking vitamin C; and the test the researchers used to rule that out was faulty.

The Mayo Clinic's bias is revealed in other ways as well. In their New England Journal report, the researchers state, "It is very clear that this study fails to show a benefit for high-dose vitamin C therapy of advanced cancer."57 The study doesn't deal with "advanced cancer" as stated--only with colon cancer. This might seem to be a minor detail, but it's the very kind of technicality that researchers are extremely careful of in order to protect themselves from future criticism. It's uncommon for researchers to overstate their case in the New England Journal of Medicine; it seems plausible that this exaggeration was included to affect the press more than to inform scientists and doctors.