The consequences of free radical damage to cells and tissues
have also been associated with the effects of aging. Although
aging is a complex,multifactorial process, one possible explanation
for many of the degenerative changes is the free radical
theory of aging (Harman, 1956). This theory proposes that free
radicals produce cell damage and that age-dependent pathologic
alterations may, at least in part, be the cumulative result of
these changes. Examples of research supporting this theory
include invertebrate studies that found the normal endogenous
production of reactive oxygen species limits lifespan (Melov et
al, 2000) and studies involving superoxide dismutase-deficient
mice that died within the first week of life (Melov, 2000).