High dose vitamin C slows tumour growth in mice

High-dose injections of vitamin C, also known as ascorbate or ascorbic acid, reduced tumor weight and growth rate by about 50 percent in mouse models of brain, ovarian, and pancreatic cancers, researchers from the National Institutes of Health (NIH) report in the Proceedings of the National Academy of Sciences.

It appears that vitamin C stimulates the production of hydrogen peroxide in the extracellular fluid surrounding the tumour, but has no effect on normal cells.

Vitamin C levels are normally carefully controlled by the body. To bypass these normal controls, NIH scientists injected ascorbate into the veins or abdominal cavities of rodents with aggressive brain, ovarian, and pancreatic tumors. By doing so, they were able to deliver high doses of ascorbate, up to 4 grams per kilogram of body weight daily.

The team then tested ascorbate injections in immune-deficient mice with rapidly spreading ovarian, pancreatic, and glioblastoma (brain) tumors. The ascorbate injections reduced tumor growth and weight by 41% to 53%. In 30% of glioblastoma controls, the cancer had spread to other organs, but the ascorbate-treated animals had no signs of disseminated cancer.

Interest in vitamin C as a potential cancer therapy peaked about 30 years ago when case series data showed a possible benefit. In 1979 and 1985, however, other researchers reported no benefit for cancer patients taking high oral doses of vitamin C in two double-blind, placebo-controlled clinical trials.