In addition to the popular saying, “An apple a day keeps the doctor away”, maybe some day we can say the phrase, “Vitamin C a day keeps cancer away”.

Who would have thought that oranges and lemons, fruits easily found in a local grocery store, may hold the answer to curing cancer? Oranges vs. cancer — it does not seem like a contest. Cancer has been winning for decades almost unmitigated. Dedicated researchers for years have diligently pursued a cure for cancer. Sometimes the paths they take are not original, but are extensions of concepts previously unexplored or not fully developed. Such is the case with treatment of cancer with vitamin C, or ascorbic acid, an essential nutrient contained in citrus fruits like oranges and lemons.

Vitamin C was previously explored as a treatment for cancer. The hydrogen peroxide generated by high concentrations of vitamin C (above 1,000 µmol/L) were found to be selectively cytotoxic to cancer cells in vitro. Normal cells were not harmed. Nobel Prize laureate in chemistry, Linus Pauling, advanced this idea in the 1970s with trials involving large doses of orally ingested ascorbic acid. The trials, unfortunately, did not show conclusive benefits and the controversial method for cancer treatment was largely ignored by most oncologists. It did, however, remain a popular alternative cancer treatment for many health practitioners.

What’s old may be becoming new again. Treating cancer with ascorbic acid is generating new buzz. This time, however, treatment will be in the form of injections of vitamin C. It turns out that no matter how many oranges, lemons, or vitamin C tablets are ingested, it does not enter the system in sufficient amounts to effect cancer cells. Only injected doses of vitamin C raise the blood level concentration to levels necessary to disrupt and harm cancer cells in laboratory experiments.

Even now, it is not universally accepted that injected vitamin C will be the successful cancer therapy that has been eluding scientists for generations. Some case reports have advanced the use of parenteral vitamin C as an agent against cancer. In three such reports, terminally ill cancer patients with pulmonary metastatic renal cancer, bladder tumor, and diffuse large B-cell lymphoma were injected with vitamin C. The patients improved significantly and had a prolonged life span. These results have not, however, passed the guidelines of the US National Cancer Institute because of insufficient data and inadequate follow-up. In addition, the cases did not have objective pathologic confirmation. So, although promising, injected vitamin C will require larger studies and conclusive benefits before expanding beyond an alternative therapy for cancer.

References

Q. Chen, M. G. Espey, A. Y. Sun, C. Pooput, K. L. Kirk, M. C. Krishna, D. B. Khosh, J. Drisko, M. Levine (2008). From the Cover: Pharmacologic doses of ascorbate act as a prooxidant and decrease growth of aggressive tumor xenografts in mice Proceedings of the National Academy of Sciences, 105 (32), 11105-11109 DOI: 10.1073/pnas.0804226105

S. J. Padayatty (2006). Intravenously administered vitamin C as cancer therapy: three cases Canadian Medical Association Journal, 174 (7), 937-942 DOI: 10.1503/cmaj.050346