Antioxidant supplements do not help much! In fact there have been studies that indicate they might do more harm than good.
Vitamins C and E and Beta Carotene Supplementation and Cancer Risk: A Randomized Controlled Trial.
Observational studies suggest that a diet high in fruits and vegetables, both of which are rich with antioxidants, may prevent cancer development. However, findings from randomized trials of the association between antioxidant use and cancer risk have been mostly negative....
Conclusions Supplementation with vitamin C, vitamin E, or beta carotene offers no overall benefits in the primary prevention of total cancer incidence or cancer mortality.