Vitamin C: Maybe Linus Pauling Wasn’t Entirely Crazy

This article was originally posted on RealClearScience.

After winning a Nobel Prize in chemistry — and yet another Nobel Prize for peace — Linus Pauling’s distinguished career took a decidedly undistinguished turn. He began promoting the idea that large doses of vitamin C could greatly reduce colds, cure cancer and improve overall health. To this day, people all over the world start popping vitamin C tablets when they get the sniffles, sadly to no effect. (One study demonstrated, however, that a daily dose of vitamin C could reduce the frequency of colds, but not the duration or severity.)

Yet, despite the general lack of credible scientific evidence to support the idea that people should take daily vitamin supplements, an entire industry has blossomed promoting just that. Unfortunately, the industry is wholeheartedly embraced by practioners of alternative medicine, pseudoscientific quacks who have enormous influence over people’s health choices. It is for these reasons that the scientific and medical communities are generally skeptical of (if not outright hostile to) new claims about the benefits of vitamin C or other supplements. 

But new research might slightly alter that viewpoint. Last week, the journal Science Translational Medicine published a study that suggests intravenous administration (i.e., injections directly into the blood) of vitamin C — when provided in combination with chemotherapy — can help increase the survival time of patients with ovarian cancer. (See figure.)

As shown in Panel C, the fraction of patients who survived for 60 months was greater for the group who received chemotherapy + vitamin C (gray line) than the group who only received chemotherapy (black line). Panel D shows that patients who received vitamin C (right column) had an additional 8.75 months of healthier life. However, due to the small sample size (22 patients total), these results were not statistically significant.

What are we to make of this study? An accompanying commentary by Melanie McConnell and Patries Herst provides some perspective.

First of all, the patients were not eating the vitamin C. The cancer-fighting effect came only from an intravenous injection. The reason is because the concentration of vitamin C needed in the blood to help fight cancer cannot be attained by ingesting vitamin C. Second, vitamin C does not cure cancer by itself; it must be used in combination with traditional chemotherapy. Finally, the commentary states that genetic differences between tumors may mean that vitamin C is not effective at fighting all cancers. Certainly, this study should be followed up with a larger clinical trial.

Though Linus Pauling is still mostly wrong, perhaps the potential therapeutic benefit of vitamin C injections could be magnanimously interpreted as a small step toward rehabilitating his tainted legacy.

Source: Y. Ma, J. Chapman, M. Levine, K. Polireddy, J. Drisko, Q. Chen, High-Dose Parenteral Ascorbate Enhanced Chemosensitivity of Ovarian Cancer and Reduced Toxicity of Chemotherapy. Sci. Transl. Med. 6, 222ra18 (2014).

Commentary: M. J. McConnell, P. M. Herst, Ascorbate Combination Therapy: New Tool in the Anticancer Toolbox?. Sci. Transl. Med. 6, 222fs6 (2014).



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