It has been thought that aging is caused by free radicals in the body, but antioxidants can fight it by destroying these free radicals. However, a recent study comparing genetically engineered nematodes that can Killfree radicals with normal ones found no difference in age and lifespan. 
The effect of genetic modification itself on the longevity of nematodes counteracts that of eliminating excess free radicals.
 it can be concluded that antioxidants have no effect on human health.