ABSTRACT
A free radical can be dened as any chemical species possessing one or several mismatched electrons. These free radicals trigger a chain reaction that damages different components of a living organism. Oxidative stress, as dened by an imbalance in the production of oxidizing chemical species, may be a causation of multiple and varied clinical entities. The effective removal of these oxidizing chemical species by protective endogenous and exogenous antioxidants and scavenger enzymes appears to be important for survival and avoidance of multiple disease entities. The role of oxidative/free radical oxygen and nitrogen species affects multiple aspects of health and disease. Antioxidants are chemical compounds that provide an electron to free radicals, converting them to a harmless conguration, thus avoiding the damaging chain reaction that variably can involve lipids, proteins, enzymes, carbohydrates, DNA, cell membranes, and nuclear membranes and that subsequently can lead to cell death. Natural antioxidants are part of the natural biochemical defenses of man and other mammals. In addition, there are nutrient antioxidants and supplemental antioxidants that must be considered. Multiple oxidant risk factors exist. There is supportive evidence that low levels of antioxidants play an important role in cardiovascular disease and cancer via an increase in harmful free radicals when antioxidants are lacking.
