Therefore, a dietary antioxidant can (sacrificially) scavenge reactive oxygen/nitrogen
species (ROS/RNS) to stop radical chain reactions, or it can inhibit the reactive oxidants from being formed in the first place(preventive). Dietary antioxidants often broadly include radical chain reaction inhibitors, metal chelators, oxidative enzyme inhibitors, and antioxidant enzyme cofactors. Selenium is a cofactor of selenoproteins (e.g., glutathione peroxidase), which reduce peroxides to alcohols and water.