(OMNS, October 7, 2008) When Memorial Sloan-Kettering Cancer Center announces that vitamin C may interfere with chemotherapy, the news media trumpet it far and wide. But before cancer patients throw away their vitamin C supplements, they need to know rest of the story.
Most of the media dutifully reported the researchers' claim that the equivalent of 2,000 mg of vitamin C "blunted the effectiveness of the chemotherapy drugs." But only some of the media included a study author's incredible statement that "If you take an oral dose even as low as 100 milligrams a day" even "that could be harmful" during chemotherapy (1)
100 mg "could be harmful"? That's the amount of vitamin C in a few glasses of orange juice. Something is very wrong here.
First of all, this research involved mice with implanted cancerous tumors; it was not a trial on cancer patients. A mouse study is a long way from a human clinical trial. This obvious difference was conceded by the study authors. However, there is a more subtle, and probably much more important factor they did not consider: all mice make their own vitamin C. Indeed, mice make quite a lot. Adjusted for body weight, mice synthesize the human body weight equivalent of approximately 10,000 milligrams of vitamin C each day. (2) Incredibly, sick mice make even more. Mice given transplanted tumors become sick mice.
Secondly, previous research has demonstrated that mice with cancer respond well to high-dose vitamin C therapy. One study found, "With an increase in the amount of ascorbic acid there is a highly significant decrease in the first-order rate constant for appearance of the first spontaneous mammary tumor. . . Striking differences were observed between the 0.076% ascorbic acid and the control groups, which synthesize the vitamin." (3) Another study concluded that: "A pronounced effect of vitamin C in decreasing the incidence and delaying the onset of malignant lesions was observed with high statistical significance. By 20 weeks, approximately five times as many mice had developed serious lesions in the zero-ascorbate as in the high-ascorbate group." (4) Interestingly enough, when this research was first publicized, the media discounted these findings saying that mouse studies were not particularly applicable to people.
Thirdly, a mouse's ability to make vitamin C, and a great deal of it, is an overlooked confounding factor that may well render the entire experiment invalid. If the Sloan-Kettering team had tried their experiment on Guinea pigs, their results might have been very different. Guinea pigs are more like human beings in that they cannot make their own vitamin C. As controls for comparison, the researchers also treated "no-added-vitamin C" mouse cancers with chemotherapy. Chemo worked just fine on those mice, by the researchers own admission. And each of those mice was internally synthesizing a body weight equivalent of 10,000 mg/day of vitamin C, even though given none supplementally.
So how come 10,000 mg of vitamin C does not interfere with chemo treatment, and 2,000 mg – or even 100 mg – supposedly does?
A sweeping recommendation warning cancer patients to not take supplemental vitamin C, not even 100 mg, is irresponsible. It is impossible to justify caution about taking 100 mg of vitamin C daily when your animal subjects made the equivalent of one hundred times that amount, and chemotherapy in them was still reported as effective. You cannot have it both ways. If a synthesized 10,000 mg of C does not interfere, there can be no real "interference" or "blunting" from a supplemental 2,000 mg. And most certainly not from 100 mg.
The study did report tumor shrinkage, in both groups of mice receiving chemo. That is not surprising. Chemotherapy's claimed success is based on tumor shrinkage. But tumor shrinkage, encouraging though it is, is not a reliable indicator of long-term cancer survival. As cancer research critic Philip Day puts it, many patients are "cured but dead" after five years, hardly a long-term survival. Day, noting that this is not because oncologists are not trying, explains the chemotherapy quandary: "You can be insincere, or you can be sincerely wrong." (5)
The Sloan-Kettering study team seems to have missed the essential point that vitamin C is not just an antioxidant. Inside cancer tumors, it also acts as a prooxidant, killing malignant cells. Comments Dr. Steve Hickey, of Manchester, UK: "Essentially, the paper seems to be rather misguided and shows a lack of understanding of the dual nature of vitamin C in tumors. Chemotherapy has been shown by over 40 years of clinical trials not to work in the majority of tumors, and its use is counter productive."
Chemotherapy drugs have come and gone; the five year survival rate for cancer treated with chemo has remained virtually unchanged for decades. Unfortunately, just over 2% of all cancers respond to chemotherapy. Specifically, one scientific review concluded, "The overall contribution of curative and adjuvant cytotoxic chemotherapy to 5-year survival in adultswas estimated to be 2.3% in Australia and 2.1% in the USA . . . chemotherapy only makes a minor contribution to cancer survival. To justify the continued funding and availability of drugs used in cytotoxic chemotherapy, a rigorous evaluation of the cost-effectiveness and impact on quality of life is urgently required." (6)
Perhaps this new, very well-publicized study results from an ever-growing realization that chemotherapy is largely ineffective, and the search is on for the reason why. Vitamin C should not be made the scapegoat.
Vitamin C, in doses well over 100 mg/day, is known to help prevent cancer. (7) Nearly 30 years ago, a review concluded that "Many factors involved in host resistance to neoplasia are significantly dependent upon the availability of ascorbate." (8) Beginning in the 1970s, many well-designed studies show that very large doses of vitamin C improve both quality and length of life for cancer patients since they invariably are "significantly depleted of ascorbic acid." When given intravenous vitamin C, "The mean survival time is more than 4.2 times as great for the ascorbate subjects . . . This simple and safe form of medication is of definite value in the treatment of patients with advanced cancer." (9) Additional clinical trials have confirmed this over the past several decades. (10)
Even more importantly, recent research indicates that in high doses, vitamin C is selectively toxic to cancer cells. That means vitamin C can function very much like chemotherapy is supposed to, but without the severe side effects of chemotherapy. "A regimen of daily pharmacologic ascorbate treatment significantly decreased growth rates of ovarian, pancreatic, and glioblastoma tumors established in mice. Similar pharmacologic concentrations were readily achieved in humans given ascorbate intravenously." (11)
"Cautioning" the public to avoid taking any supplemental amount of vitamin C will decrease host resistance to cancer, increase the incidence of this dreaded disease, and shorten survival times. A cynic might say it will also create a larger market for chemotherapy.
Is vitamin C a commercial competitor for chemo? To answer this, one needs to consider what appears to be serious conflict of interest at Sloan-Kettering. Bristol-Myers-Squibb makes chemotherapeutic drugs. According to a DEF 14A SEC filing of March 22, 2006, the Chairman of the Board of Bristol-Myers-Squibb is also a director of the Coca-Cola Company, and Honorary Chairman of Memorial Sloan-Kettering Cancer Center. A previous Bristol-Myers-Squibb Chairman of the Board was a director of the New York Times Company. He was also Vice Chairman of the Board of Overseers and the Board of Managers of Memorial Sloan-Kettering Cancer Center and Chairman of the Board of Managers of Sloan-Kettering Institute for Cancer Research. (http://www.secinfo.com/dsvrt.bC7.htm) Some sources say that there are even more Bristol-Myers-Squibb directors who have or held positions on the board at Memorial Sloan-Kettering Cancer Center. (12)
Positive endorsements for vitamin C as a cancer fighter are not in the interests of any pharmaceutical company. Scaring the public away from vitamin C might be profitable. It appears that Sloan-Kettering is biased. So are media reports that attack vitamins.
If the Sloan-Kettering study authors' recommendations to not take 2,000 mg, or even 100 mg, of vitamin C are followed, there will definitely be an increase in the number of people that need chemotherapy.
(1) Doheny K. Vitamin C and chemotherapy: bad combo? Supplementing with vitamin C may reduce effectiveness of chemotherapy drugs, study shows. WebMD Health News.
(2) Chatterjee IB, Majumder AK, Nandi BK, Subramanian N. Synthesis and some major functions of vitamin C in animals. Ann N Y Acad Sci. 1975 Sep 30;258:24-47.
(3) Pauling L, Nixon JC, Stitt F et al. Effect of dietary ascorbic acid on the incidence of spontaneous mammary tumors in RIII mice. Proc Natl Acad Sci U S A. 1985 Aug;82(15):5185-9.
(4) Pauling L. Effect of ascorbic acid on incidence of spontaneous mammary tumors and UV-light-induced skin tumors in mice. Am J Clin Nutr. 1991 Dec;54(6 Suppl):1252S-1255S. Read the full paper free of charge at http://www.ajcn.org/cgi/reprint/54/6/1252S
(5) Day P. in the documentary film Food Matters, http://www.foodmatters.tv See also: Day P. Cancer: why we're still dying to know the truth. Credence Publications , 1999. ISBN-10: 0953501248; SBN-13: 978-0953501243
(6) Morgan G, Ward R, Barton M. The contribution of cytotoxic chemotherapy to 5-year survival in adult malignancies. Clin Oncol (R Coll Radiol). 2004 Dec;16(8):549-60.
(7) Enstrom JE, Kanim LE, Klein MA. Vitamin C intake and mortality among a sample of the United States population. Epidemiology. 1992 May;3(3):194-202.
(8) Cameron E, Pauling L, Leibovitz B. Ascorbic acid and cancer: a review. Cancer Res. 1979 Mar;39(3):663-81.
(9) Cameron E, Pauling L. Supplemental ascorbate in the supportive treatment of cancer: Prolongation of survival times in terminal human cancer. Proc Natl Acad Sci U S A. 1976 Oct;73(10):3685-9. Read the original paper at http://profiles.nlm.nih.gov/MM/B/B/K/Z/_/mmbbkz.pdf
(10) Murata A, Morishige F, and Yamaguchi H. Prolongation of survival times of terminal cancer patients by administration of large doses of ascorbate. International Journal of Vitamin and Nutrition Research Suppl., 23, 1982. p. 103-113. And: Null G, Robins H, Tanenbaum, M, and Jennings P. Vitamin C and the treatment of cancer: abstracts and commentary from the scientific literature. The Townsend Letter for Doctors and Patients, 1997. April/May. And: Vitamin C and cancer revisited. Proc Natl Acad Sci U S A. 2008 Aug 12;105(32):11037-8. Also: Riordan HD, Riordan NH, Jackson JA et al. Intravenous vitamin C as a chemotherapy agent: a report on clinical cases. Puerto Rico Health Sciences J, June 2004, 23(2): 115-118.
(11) Chen Q, Espey MG, Sun AY et al. Pharmacologic doses of ascorbate act as a prooxidant and decrease growth of aggressive tumor xenografts in mice. Proc Natl Acad Sci U S A. 2008 Aug 12;105(32):11105-9. See also: Chen Q, Espey MG, Sun AY et al. Ascorbate in pharmacologic concentrations selectively generates ascorbate radical and hydrogen peroxide in extracellular fluid in vivo. Proc Natl Acad Sci U S A. 2007 May 22;104(21):8749-54. And: Chen Q, Espey MG, Krishna MC et al. Pharmacologic ascorbic acid concentrations selectively kill cancer cells: action as a pro-drug to deliver hydrogen peroxide to tissues. Proc Natl Acad Sci U S A. 2005 Sep 20;102(38):13604-9. And: Padayatty et al. Intravenously administered vitamin C as cancer therapy: three cases. Canadian Medical Association Journal, 2006. 174(7), March 28, p 937-942. http://www.cmaj.ca/cgi/reprint/174/7/937. Also: Riordan NH et al. Intravenous ascorbate as a tumor cytotoxic chemotherapeutic agent. Medical Hypotheses, 1995. 44(3). p 207-213, March.
(12) Moss R. Questioning Chemotherapy. Equinox Press, 1995. ISBN-10: 188102525X; ISBN-13: 978-1881025252. See also: The Cancer Industry. Equinox Press, 1996. ISBN-10: 1881025098; ISBN-13: 978-1881025092.
For more information:
Cameron E. and Pauling L. Cancer and vitamin C, revised edition. Philadelphia: Camino Books, 1993.
Hickey S and Roberts H. Cancer: nutrition and survival. Lulu Press, 2005. ISBN: 141166339X.
Hoffer A. Healing cancer: complementary vitamin and drug treatments. Ontario: CCNM Press, 2004. ISBN-10: 1897025114; ISBN-13: 978-1897025116.
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