Antioxidants: Differing Meanings in Food Science and Health Science.

"Antioxidant" is a term commonly used in food science to describe compounds that block lipid peroxidation and other oxidative reactions, thereby maintaining freshness and prolonging the shelf lives of food products. Dietary antioxidants and antioxidant supplements are lauded as quenching reactive oxygen species and preventing different chronic diseases, but strong evidence for their beneficial effects is lacking. In addition to the essential antioxidant nutrients, vitamins E and C, there are several well-designed antioxidant and cytoprotective enzyme systems in the human body, which are more important than dietary non-nutrient antioxidants. At high concentrations, many antioxidants could act as pro-oxidants, increasing oxidative stress and inducing toxicity.