Vitamin C reduces tumour growth – an orange a day keeps the doctor away

Intravenous administration of high-dose vitamin C has been shown to reduce growth of aggressive tumour xenografts in mice (Proceedings of the National Academy of Sciences, 4 August 2008).

The authors suggest that previous studies of vitamin C did not show benefits for cancer patients because plasma and tissue concentrations of vitamin C are tightly regulated by the body when the vitamin is given orally, and that parenteral dosing can circumvent this phenomenon. They propose that IV vitamin C generates hydrogen peroxide in the tumour interstitium, which has a cytotoxic effect.