Injections of high doses of vitamin C slowed the growth of tumors in mice by 50 percent, and also prevented the cancers from metastasizing to other parts of the body. Researchers
say the findings form a "firm basis" for trials in humans, with a view to using vitamin C injections alongside conventional drugs, particularly for some of the most lethal tumours, such as pancreatic, ovarian and brain cancer [The Guardian].
But some cancer specialists are sceptical, and fear that desperate patients will be prompted to start taking large doses of the vitamin. That may be dangerous, because antioxidants such as vitamin C could undermine the effectiveness of standard cancer drugs and radiation therapy [New Scientist].
Researchers point out that they were only able to deliver a higher dose of the vitamin through intravenous injection and that patients couldn't get a similar dose through diet or vitamin supplements, because the digestive system can absorb a limited amount of the vitamin. The study, published in the Proceedings of the National Academy of Sciences [subscription required], is the latest of several reversals on the efficacy of vitamin C as a cancer fighter.
The interest in the vitamin dates back to 1948 when a doctor - William McCormick - speculated about an anti-cancer effect of vitamin C and this idea was followed up in the early Seventies by the Scot Ewan Cameron and the late Nobel laureate Linus Pauling [Telegraph].
But two 1985 studies showed conclusively that the vitamin had no beneficial effects on cancer patients when taken orally. In the current study, researchers gave vitamin shots to mice with pancreatic, brain, and ovarian cancer, and found that the tumors grew much slower in mice that had received the vitamin boost compared to mice that didn't get the shot.
The treatment works because a tumour cell is chemically different to a healthy cell. The vitamin C reacts with this chemical make-up, producing enough hydrogen peroxide to kill the cell, while leaving healthy cells unscathed [BBC News].
Image: Mark Levine
