The Truth About Vitamin C and Cancer

studies show vitamin c can help cancer treatments

In the 1960’s, two-time Nobel prize winning chemist, Linus Pauling, asserted that high doses of intravenous vitamin C could treat everything from heart disease to cancer. The medical community quickly launched their own investigation, but clinical trials conducted by the Mayo Clinic concluded that high-dose vitamin C was no better than placebo at treating cancer and that there was no benefit to high-dose vitamin C, leaving a bias and hindering research for years.

Fast forward to the 21st century. A 2009 review in the journal Anticancer Research was actually partial to Pauling, noting that there were significant methodological differences between the Mayo Clinic’s and Pauling’s studies; most notably, the Mayo Clinic did not use intravenous Vitamin C, but rather administered it orally. They also found that other researchers administering intravenous vitamin C to patients reported that the patients gained benefits such as increased survival, improved wellbeing and reduced pain. They noted that intravenous administration is necessary to achieve high enough plasma levels for a pharmacological effect, and that convergent evidence shows that Vitamin C is effective as an anticancer agent.

Five years later, vitamin C and cancer are back in the news. In new research published in the February 2014 issue of Science Translational Medicine, scientists found that high doses of vitamin C – administered intravenously – increased the cancer-killing effects of chemotherapy drugs in mice, while alleviating toxic side effects in humans.

Researchers examined the effects of vitamin C on a variety of cancer cells in the lab, and in ovarian cancer cells in mice. When high concentrations of ascorbate (vitamin C) entered the space between cells, they said, it formed hydrogen peroxide.

Senior author Qi Chen, an assistant professor of pharmacology, toxicology and therapeutics at the University of Kansas, said the hydrogen peroxide went to work on cancerous cells in several ways: It damaged their DNA, it stressed their metabolism and inhibited their growth. This weakening improved the effectiveness of traditional cancer drugs like carboplatin and paclitaxel.

Surprisingly, the hydrogen peroxide did not harm the non-cancerous cells. While researchers said it remains unclear exactly why this is the case, they suspect it has to do with the inefficient way cancer cells convert glucose to energy, when compared with regular cells.

A third part of the research involved a small trial study with 27 cancer patients, a portion of whom were given vitamin C with chemotherapy, provided they did not have kidney problems. The purpose of the trial was to see if the vitamin C sickened patients, not whether it was more effective than standard treatment. Many more patients would be required to make that determination.

Not only did the patients who were given vitamin C do well, they tolerated chemotherapy better than those who did not receive it, the authors said. They had more energy, and experienced less nausea.

Unfortunately even though the research seems to offer the promise of effectiveness for a new method of cancer treatment and despite the fact that high-dose vitamin C is currently administered intravenously to thousands of patients by practitioners of complementary and alternative medicine, vitamin C is unlikely to inspire the vigorous, and expensive research necessary to become an approved cancer treatment.

Even if more studies confirmed that vitamin C can help fight cancer, someone would have to steer it through the Food and Drug Administration’s lengthy approval process. Vitamin C is an essential nutrient and therefore can’t be patented, so pharmaceutical companies have no incentive. This leaves vitamin C among the most unlikely compounds to attract funding for cancer research, despite being a safe, inexpensive alternative.