Antioxidants break up the chains formed during the propagation process of the redox system by providing a hydrogen atom of an electron to the free radical and receiving the excess energy possessed by the activated molecule. The important role of dietary antioxidants in maintaining the integrity of living organisms is gaining ever-increasing recognition. New data are constantly gathered to show the role of oxidative stress and the involvement of reactive oxygen species and reactive nitrogen species in the pathogenesis of degenerative diseases. These diseases are associated with a disturbance in the necessary balance between the oxidation and the reduction status in blood and tissues, leading to oxidation of lipids, proteins and nucleic acids. Such oxidative damage is accompanied by changes in the macromolcular structure and function and by the manifestation of clinical disorders such as cardiovascular diseases and cancer. Hence, widespread research is being conducted aiming to investigate the possible effects and mechanisms of action of dietary antioxidants in these diseases. Antioxidants may exert their effect on biological systems by different mechanisms, including electron donation (as reducing agents), metal ion chelation (thereby eliminating potential free radicals), sparing of antioxidants (co-antioxidants) or by regulation of gene expression. Optimized content for mobile and hand-held devicesHTML pages have been optimized of mobile and other hand-held devices (such as iPad, Kindle, iPod) for faster browsing speed. Click on [Mobile Full text] from Table of Contents page. This is simple HTML version for faster download on mobiles (if viewed on desktop, it will be automatically redirected to full HTML version)