Vitamin C: possible cancer-killing promise

Studies during the 1970s first suggested administration of high doses of ascorbate might provide a clinical benefit for treating cancer, but later studies using the same high doses found no benefit.

However, researchers now say the original studies used intravenous and oral ascorbate, while subsequent studies used only oral administration. Recognizing those differences might account for the disparate clinical outcomes, Mark Levine and colleagues at the National Institutes of Health reexamined intravenous ascorbate therapy in cultured cancer cell lines.

The researchers found ascorbate killed cancer cells at concentrations that would only be achievable through intravenous infusion. Normal cells were not affected by ascorbate at any concentration.

Additionally, the scientists report ascorbate treatment led to the formation of hydrogen peroxide, a chemical that can kill cells, suggesting a potential mechanism for the therapy.

The research appears in this week's online, early edition of the Proceedings of the National Academy of Sciences.

Copyright 2005 by United Press International