High doses of antioxidants such as vitamin C are believed to prevent cancer by mopping up free radicals which can damage DNA. However, a study by Dutch researchers has shown that free radicals can also kill cancer cells. If so, antioxidants may be bad for cancer sufferers because they remove free radicals.
The study, by scientists at Nijmegen University in the Netherlands, involved creating a cancerous cell line by damaging the P53 suppressor gene which makes a protein triggering programmed cell death ("apoptosis") in tumour cells. With the gene damaged, tumour cells are able to survive and spread.
The researchers then raised the level of antioxidants in the cancer cells so that the free radical levels fell. This reduced the death rate of the cancer cells, they say. The results, reported in New Scientist are to be published in an academic scientific journal later. The researchers say an anti-cancer drug capable of generating free radicals may be effective against cancer but is still a long way off.