It has been shown, that accumulation of free radical damage and its catalysis by various oxidants including quinones and other age pigments, metal ions, lipid peroxides, prostaglandins and components released from cells, increase with age. But biological systems have evolved a multiplicy of defences against oxidative attack.
Support for the free radical theory of aging has increased progressively and now includes:
studies on the origin of life and
evolution
studies on the effect of ionizing radiation on living
things
dietary manipulations of endogenous free radical
reactions
the plausible explanations it provides for aging
phenomena
the growing numbers of studies that implicate
free radical reactions in the pathogenesis of specific diseases.