a two-edged sword?

Vitamin C could promote production of DNA-damaging compounds according to a study published in the June 15 issue of Science. Mutations caused by these compounds have been found in a variety of tumours. New findings by University of Pennsylvania researchers may help explain why vitamin C has thus far shown little effectiveness at preventing cancer in clinical trials. This dual activity of vitamin C has been studied by others both in vitro and in human subjects, notably by Joseph Lunec of the University of Leicester. But, the chemical mechanism behind this behaviour has not been elucidated until publication of the University of Pennsylvania study.

Vitamin C, known chemically as ascorbic acid, can act as an antioxidant, consuming free radicals and thereby preventing free radical induced DNA damage. Free radicals are highly reactive chemical species produced by the reaction of oxygen with biological molecules, a chemical reaction that occurs constantly in ...