ABSTRACT
Food and oxygen are both essential for survival of human life and are intrinsically involved in chemical reactions which initiate, regulate, and modify toxicity in the living organism. The exposure of living organisms to the 20.9% oxygen present in air contributes to the dependency on biological oxidation reactions as a source of energy for growth and maintenance. Under normal conditions, approximately 2% of the oxygen consumed by mitochondria is incompletely reduced, resulting in the generation of oxygen radicals (1). The body’s antioxidant status is comprised of endogenous antioxidant enzymes [e.g., superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px] as the first line of defense against reactive oxygen species. In addition, nonenzymatic antioxidants are also required to collectively deactivate reactive oxygen species and reduce oxidative stress. These two systems combined, attenuate the accumulation of toxic oxygen species, thereby protecting the organism against cellular membrane damage and acute or chronic tissue dysfunction-associated pathologies that may lead to chronic disease and aging. The role of nutrition in maintaining adequate protection against endogenous and exogenous forms of oxidative stress is an important component of nutritional toxicology (2).
