"Vitamin 'may blunt cancer drugs'" from BBC News reports that Vitamin C supplements may, contrary to what might seem logical, blunt the effectiveness of a range of anti-cancer drugs.
Thirty to 70% less cancer cells in a lab were killed by a range of drugs, after pretreatment with vitamin C.
Follow-up chemotherapy tests found tumours grew more rapidly in mice given cancer pretreated with vitamin C.
Cancer Research reports the Memorial Sloan-Kettering Cancer Center findings. The US researchers say the same mechanism may affect patient outcomes.
Some studies have suggested that because vitamin C is an antioxidant it could be beneficial to cancer patients.