Linus Pauling Stands By His Claim : Second Study Fails to Show Vitamin C Fights Cancer
For the second time in five years, a scientifically conducted study by Mayo Clinic researchers has failed to confirm claims by Nobel Prize winner Linus C. Pauling that large daily doses of Vitamin C increase the length of survival of patients with advanced terminal cancer.
Although the report probably will not end the decade-long debate over Vitamin C’s potential as an anti-cancer agent, physicians are expected to take the results into consideration when advising patients with advanced cancer who ask about the vitamin’s benefits.
Pauling, who won the Nobel Prize in chemistry in 1954 and the Nobel Peace Prize in 1962, challenged the results of the first Mayo study, contending that it failed to find any benefit from Vitamin C because the patients in the study group had received toxic anti-cancer drugs. He claimed that those drugs interfered with the ability of Vitamin C to stimulate the patients’ natural defense mechanisms.
The latest study, reported in today’s issue of the New England Journal of Medicine, was conducted to learn whether anti-cancer drugs had anything to do with the failure of the first study to find Vitamin C effective in extending lives of cancer patients.
After studying 100 patients--half of whom received 10 grams of Vitamin C daily and half of whom were given sugar pills--Mayo researchers concluded that the vitamin dosage, which has been recommended by Pauling, had no effect on increasing the survival of patients, even those who had never received chemotherapy.
‘Unprofessional Manner’ Nevertheless, in an interview with the Associated Press, Pauling stood by his recommendation concerning Vitamin C. He said that the vitamin does no harm to cancer patients and that he believes it might do some good.
Pauling said he could not comment on the specifics of the latest study because he had not read it.
“I think that (the Mayo researchers) have behaved in an unprofessional manner in failing to send me a copy of the paper to me before publication,” Pauling added.
The debate over the value of Vitamin C dates to 1974, when Dr. Ewan Cameron, a Scot surgeon, published a report saying that a high daily dose of the vitamin could cause tumors to regress in some cancer patients.
In 1976, Pauling and Cameron collaborated on a report in which they compared the length of survival of 100 advanced cancer patients who had received Vitamin C with the survival times of 1,000 control patients who had died over a period of years without having received Vitamin C.
That report attracted considerable public attention and resulted in widespread use of the vitamin by cancer patients.
Three years later, Dr. Charles G. Moertel, director of the Mayo Clinic cancer center, said he and his colleagues had repeated the study conducted by Cameron and Pauling and found no difference in the survival of patients who had taken Vitamin C and another group given sugar pills.
Publication of the first Mayo report touched off another round of heated debate between Pauling supporters and most cancer experts.
Because Pauling’s chief criticism centered around the issue of chemotherapy, Moertel then launched a second study in which none of the 100 patients who took part had previously received anti-cancer drugs.
The latest trial involved only patients with cancer of the large bowel because, Moertel said, this was the most frequent tumor type in Cameron’s and Pauling’s study and one for which they claimed a striking improvement in survival with Vitamin C. Half of the patients received the vitamin and the other half were given placebo medication.
“No patient had measurable tumor shrinkage, the malignant disease in patients taking Vitamin C progressed just as rapidly as in those taking placebo and patients lived just as long on sugar pills as on high-dose Vitamin C,” the Mayo team said.
Opposite Result “Surprisingly, and perhaps by chance, there were more long-term survivors receiving placebo than Vitamin C.”
Unlike Cameron’s and Pauling’s study, Moertel’s was double blinded, meaning that the researchers did not know which patients in the study were receiving Vitamin C and which ones received sugar pills.
In attempting to determine why Cameron’s and Pauling’s 100 cancer patients lived many times longer than patients the control group to which they were compared, the Mayo team said, “We are left with the inevitable conclusion that the apparent positive results of Cameron and Pauling were the product of case-selection bias rather than treatment effectiveness.
“Whether one is dealing with the treatment of the common cold or of cancer,” they continued, “and whether one is dealing with a benign vitamin or a highly toxic chemotherapy program, it would seem to serve the interest of the patient best for public advocacy of a proposed treatment to be withheld until that treatment had been proved effective by definitive studies of sound scientific design.”
Pauling, however, questioned that statement.
“I hear from patients who say their doctor said, ‘If you want to take Vitamin C, go ahead and do it. It won’t harm you, and it may do you some good.’ More and more physicians are getting convinced about the value of large doses of Vitamin C,” he told the Associated Press.
