Why Vitamin C? Cancer Fighting Properties

Ewan Cameron, Ava Helen and Linus Pauling. Glasgow, Scotland, October 1976.

[An analysis of Ewan Cameron and Linus Pauling’s book, Cancer and Vitamin C. This is part 2 of 9.]

In their 1979 book, Cancer and Vitamin C, Ewan Cameron and Linus Pauling argued that vitamin C could be used to effectively treat cancer. With such a bold claim having been issued, vitamin C now needed to do a lot of heavy lifting. More specifically, Pauling and Cameron needed to prove that vitamin C could a) effectively treat cancer and also b) do so better than other substances being used to treat and cure cancer. As such, the authors devoted nearly half of their book to exploring vitamin C’s unique properties, with particular attention naturally paid to its cancer-fighting abilities.

In doing so, Cameron and Pauling first examined known cancer-causing agents on the cellular level and then investigated how vitamin C interreacted with these agents. One such substance was the enzyme hyaluronidase. When Pauling and Cameron were writing their book, it was widely recognized that certain malignant tumors released this enzyme and that, when exposed to healthy tissues, the enzyme would break down the glycosaminoglycans, which might be likened to the “cement” that makes tissues strong. As the cement became weaker, the tissues grew more vulnerable to being penetrated by cancer cells. By extension, it was believed that hyaluronidase promoted the spread of malignant cells within the body. It was also suspected that cancer cells released a different enzyme, collagenase, which would break down the collagen in tissues, further weakening cells and making them more susceptible to disease.

Having established this, Pauling and Cameron then illustrated the role that vitamin C could play in obstructing this process. Studies had found that vitamin C naturally helps to produce a hyaluronidase inhibitor, which in effect blocks the enzyme and stops the destruction of the tissue cement. Furthermore, vitamin C is known to be a necessary component for the building of collagen, and it was proposed that increased intake of vitamin C could boost collagen production and strengthen cells even more.

When Pauling and Cameron published their first edition, some of the ideas regarding hyaluronidase and collagenase were speculative. Pauling and Cameron were also relying on their collective scientific expertise to develop a model for vitamin C’s interactions with these enzymes. Pauling was not shy about making informed inferences to explain scientific phenomena, and in the case of vitamin C and these two enzymes, his thinking appears to have been correct. Since the publication of the first edition of Cancer and Vitamin C, two different research teams have published articles (in 2001, 2004, 2010, and 2011) which found evidence that vitamin C does in fact help to inhibit hyaluronidase.

More recent research has also suggested that high levels of vitamin C generate hydrogen peroxide. While it is not clear what the exact mechanism is that causes this, it is known that hydrogen peroxide can lead to a type of cell death that turns out to be useful in the cancer fight. Most healthy cells are not impacted by hydrogen peroxide because of the presence of an enzyme, catalase, that neutralizes its impact. Cancer cells, on the other hand, are not equipped with catalase; or if they are, the amount is negligible. So it is now well-established that hydrogen peroxide can kill cancer cells, but getting sufficient quantities of hydrogen peroxide to cancer cells inside the body has proven challenging. By administering large doses of vitamin C, it is hoped that clinicians may someday be able to provide targeted hydrogen peroxide therapy to patients who could benefit from it.


While Pauling and Cameron were able to provide data-based connections between vitamin C and its ability to fight cancer, their book also includes more anecdotal ideas that support their argument. One such observation was that patients who were given vitamin C for cancer treatment tended to experience less severe side effects from chemotherapeutics than those who did not take vitamin C. Although it was hard to quantify, Pauling and Cameron noted several instances where bed-ridden patients under Cameron’s care would take vitamin C and soon be capable of moving about. Cameron also observed that patients who stopped taking vitamin C often saw their symptoms rapidly return.

More notably, several of Cameron’s patients who were given vitamin C were found to go into remission. Because of ethical concerns related to placebo trials, Cameron and Pauling did not have any controls to support their claims. However, many of the patients took no treatment other than vitamin C, and Cameron, who had been a practicing physician for many years prior to beginning work on vitamin C therapy, understood that remissions for many of these cancers was not at all common.

To further support the notion that there was something special about vitamin C, Pauling and Cameron also observed that healthy people could not tolerate as much supplemental vitamin C as could those suffering from cancer. That is to say, healthy patients could take only so much vitamin C before they began to experience side effects, such as diarrhea, than was the case with cancer patients. This anecdote suggested to the authors that cancer patients needed a large amount of vitamin C – all of it was, in effect, being used, and as such there were no negative side effects. In fact, the appropriate dosage was often determined by giving a patient as much as they could tolerate before experiencing side effects.


Pauling and Cameron knew that vitamin C helped fight cancer. They saw that their patients were getting better and, from a molecular viewpoint, the mechanisms involved made sense, even if the data wasn’t in hand to prove everything. But there was more to support vitamin C as a model substance for treating cancer, and that had to do with its connection to scurvy, which we will explore in our next post.

Ewan Cameron

Ewan Cameron, 1976

“Today I propose to tell you of my personal involvement in this still highly controversial subject, the vitamin C in cancer story. The matter is capable of arousing almost any emotion from bitter prejudice and blazing anger on the one hand, to unbridled (and undeserved) enthusiasm on the other, with all grades of scorn, laughter, ridicule, and pity in between. I hope to convince you that the whole research project has a perfectly sound scientific basis, and that Dr. Pauling and I are neither gullible fools, nor are we charlatans.”

-Ewan Cameron, “Vitamin C and Cancer: A Personal Perspective,” September 1984.

Ewan Cameron, about whom we’ve written before, was born in Glasgow, Scotland on July 31, 1922. His interest in medicine emerged early in life and at the age of twenty-one he was interning in surgery and medicine in several Scottish hospitals.  One year later he received the British equivalent of an M.D. degree from the University of Glasgow and shortly thereafter was stationed in Burma, performing surgeries as a Lieutenant Colonel in the British Army Reserve at the close of World War II.

Following his three years of active military service, Cameron returned to Scotland and resumed his training in surgery and radiotherapy. In 1956, at the age of 33, he was appointed Consultant Surgeon at Vale of Leven District Hospital in Dunbartonshire, Scotland – at the time, Cameron was the youngest such appointee in all of the U. K.

Cameron’s formal association with Vale of Leven would last for twenty-six years, and it is during this period that he formulated an important theory on the nature of cancer. Cameron’s idea was that the malignant invasiveness of cancer cells might be combated by manipulating hyaluronidase inhibitor, a naturally-occurring substance that controls the hyaluronidase enzyme liberated by malignant tumors. The theory, which Cameron developed for at least eleven years before publishing, was founded on the notion of fighting cancer through the strengthening of the human body’s natural protective mechanisms.

In 1971 Cameron further hypothesized that vitamin C was required for the body’s synthesis of hyaluronidase inhibitor, and thereafter noted promising results for those terminally-ill cancer patients at Vale of Leven being treated with ten daily grams of ascorbic acid. This line of inquiry was a natural fit for work being conducted several thousand miles away by Linus Pauling. Cameron recalled

Just as the idea evolved, I learned that Professor Linus Pauling had stated that vitamin C might be helpful for cancer patients. My first reaction was one of dismay, even defeat, but such a feeling did not last very long. I wrote immediately to Dr. Pauling and we have been close collaborators ever since. Dr. Pauling had reasoned that an adequacy of vitamin C (necessary for collagen formation) might increase the scirrhous reaction and help encapsulate tumors. On further reading we realized that vitamin C was involved in many other aspects of host resistance, such as cell-mediated immunity and the biosynthesis of interferon. Many independent investigators subsequently were able to show that ascorbate administered in the gram range enhanced these defensive mechanisms to levels of activity far above the so-called normal range. Therefore, there is a strong case for the expectation that supplemental vitamin C, in adequate dosage, might have some beneficial effect against cancer.

Thus began a fruitful partnership resulting in ten papers co-authored by Cameron and Pauling on the potential value of vitamin C in the treatment of cancer.

Ewan Cameron, Ava Helen and Linus Pauling, Glasgow, 1976.

In 1978 Cameron accepted Pauling’s offer of appointment as Chief Medical Officer at the Linus Pauling Institute of Science and Medicine, and moved with his family to California. A year later, Pauling and Cameron published Cancer and Vitamin C, a book-length description of their work written for a more general audience. Initially self-published by the Institute, the book was eventually translated into French and Japanese.

Cameron and Pauling continued to work on the cancer question throughout the 1980s, at points turning their attentions to ascorbic acid’s potential value to those suffering with AIDS. Amidst it all, the duo was routinely attacked by the mainstream medical establishment – a source of tremendous frustration for both Pauling and Cameron. In concluding his 1984 talk, Cameron provided a glimpse into the resentment that the bad press had engendered.

Despite unethical and unprofessional well-publicized attacks on our integrity in the media by Mayo Clinic investigators on the basis of two very seriously flawed trials, I remain convinced that the value of supplemental ascorbate has now been proven beyond a shadow of a doubt, and that in time supplemental ascorbate will come to form a part of all comprehensive cancer treatment regimens. It appears that the general public is already ahead of the medical profession in reaching such a decision.

Ewan Cameron died on March 21, 1991, aged 68, of prostate cancer – the same disease which ultimately claimed Linus Pauling’s life three and a half years later. To date no clear consensus has been reached on the body of work created by the Pauling-Cameron collaboration, though it is worth noting that research published in August 2008 by the National Institutes of Health reported that “High-dose injections of vitamin C, also known as ascorbate or ascorbic acid, reduced tumor weight and growth rate by about 50 percent in mouse models of brain, ovarian, and pancreatic cancers.”

The Ewan Cameron Papers is just one of the many collections housed in the Oregon State University Libraries Special Collections.