From ScienCentral, more on recent research into free radicals and aging: "Rabinovitch's group genetically engineered mice to produce a natural antioxidant enzyme called catalase. The mice lived 20 percent longer than normal mice - on average they lived five and a half months longer than the control animals, whose average life span was about two years. ... It means that an individual who lives to age 70, now, with the benefits that we achieved in the mice if these could be carried forth to humans, they might live instead to 84 years old. What we have achieved is the best documentation yet that increasing the level of antioxidants in a general fashion can enhance the health and the lifespan of mice."