Best thing to do is to reduce your risk of getting cancer, and when the above mentioned fruit and veg (UCL suggests 7 a day) it allows you to get antioxidants. and i'll add eat a balanced diet, personally and many others suggest vegetarian, like pulses and other non processed foods.
Basically an antioxidant is a molecule that inhibits the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent. Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions. When the chain reaction occurs in a cell, it can cause damage or death to the cell. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions.