The idea that vitamin C might have potential in cancer treatment has been around for decades. Perhaps the late Dr. Linus Pauling is most linked with this concept. With his death, it seemed that interest in his ideas died a bit, too. However, some scientists have continued to be interested in the subject.
For example, The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK, part of the National Institutes of Health) has continued to research this topic. In fact, this organization published a paper recently that found that injecting vitamin C in the abdomens of mice led to a decrease in the size of tumors that had been induced in them [1].
A commentary article from two scientists at the Linus Pauling Institute in Oregon accompanied this paper. [2]. The authors of the commentary (Balz Frie and Stephen Lawson) highlight the fact that the work from NIDDK shows that vitamin C at high dose has been shown to be toxic to cancer cells, but leaves normal cells alone.
This quality is, obviously, highly desirable if we’re seeking to combat cancer but wish to leave the rest of the body unscathed. Frie and Lawson discuss how high doses of vitamin C can increase production of hydrogen peroxide, which is thought to be the principal substance that accounts for vitamin C’s anti-cancer properties.
Frie and Lawson go on to highlight some of the other evidence in the area. They refer to a study published in 1974 in which 50 patients with advanced cancer were treated with intravenous infusions of vitamin C (doses of 5–45 grams per day) or oral doses (at doses of 5–20 grams per day) [3]. In 19 of these patients, there was retardation, stabilization, or regression of their tumors.
They also cite another study in which the outcomes of 100 individuals treated with vitamin C (intravenous and oral vitamin C at a dose of about 10 grams per day) were compared with a control group (who did not receive vitamin C) [4]. Patients treated with vitamin C survived approximately four times longer than those in the control group.
A follow-up study reported that patients given vitamin C had an average survival time almost one year longer than the control group [5]. Overall, 22 percent of the vitamin C-treated group survived for more than a year, compared to only 0.4 percent of non-treated control group.
Frei and Lawson also refer to two randomized, placebo-controlled, double-blind trials of vitamin C and advanced cancer sponsored by the National Cancer Institute. Neither of these trials showed a positive effect from vitamin C in terms of survival. However, these trials used oral vitamin C alone and, as Frei and Lawson point out, it is unlikely that sufficient levels of vitamin C would have been achieved for benefit to be possible.
The authors go on to point to two recent studies that have tested the safety of high doses of vitamin C in humans. Once certain conditions have been screened for, it seems humans have enormous tolerance for vitamin C.
They end by saying that the scientists who produced the recent work in mice are now poised to explore the potential value of high-dose vitamin C for the treatment of cancer in humans. Let’s hope that its cheap price and non-patentable status do not hold back interest in this nutrient as an anti-cancer agent.
References:
1. Chen Q, et al. Pharmacologic doses of ascorbate act as a pro-oxidant and decrease growth of aggressive tumor xenografts in mice. Proceedings of the National Academy of Sciences 2008; 105:11105–11109
2. Frei B, et al. Vitamin C and cancer revisited. Proceedings of the National Academy of Sciences 2008; 105(32): 11037–11038
3. Cameron E, et al. The orthomolecular treatment of cancer. II. Clinical trial of high-dose ascorbic acid supplements in advanced human cancer. Chemico-Biological Interactions 1974; 9:285–315.
4. Cameron E, et al. Supplemental ascorbate in the supportive treatment of cancer: Prolongation of survival times in terminal human cancer. Proceedings of the National Academy of Sciences 1976; 73:3685–3689.
5. Cameron E, et al. Supplemental ascorbate in the supportive treatment of cancer: Reevaluation of prolongation of survival times in terminal human cancer. 1978; Proceedings of the National Academy of Sciences USA 75:4538–4542.
Dr. John Briffa is a London-based physician and author with an interest in nutrition and natural medicine.
Dr. Briffa’s Web site
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