The Issues of Antioxidant Therapy

Abstract

Interest in antioxidants and antioxidant therapy has been growing during the last decade. Antioxidants are generally considered to have the capability to protect people from harmful effects of reactive oxygen and nitrogen species (RONSs), including free radicals (FR), when these are present in excessive amounts. RONS and free radicals perform a variety of useful biological functions in the body. Their excess is controlled by a natural antioxidant protection system in humans. This protection is provided at three levels: by simple molecules (such as cysteine, glutathione (GSH), uric acid, ubiquinol, etc.), medium-molecular weight, and high molecular weight compounds (enzymes, etc.). Under certain adverse conditions, this system does not manage to provide adequate protection and the RONSs and free radicals begin to damage vital DNA, proteins, and lipids. In such a case, antioxidant therapy, which includes antioxidant supplements and foods containing natural antioxidants, has been suggested to be of possible benefit. However, there are many unresolved issues related to the effective use of an antioxidant therapy