Chapter 16 – Antioxidants in Health and Disease

Antioxidants are a loosely characterized group of compounds that are defined by their general ability to decrease or delay oxidative reactions. Dietary antioxidants are recognized to have the ability to inhibit the formation of both reactive oxygen species and reactive nitrogen species, which can adversely affect normal cellular processes and physiological functions. Under normal conditions, the balance between production and elimination of free radicals is maintained by endogenous enzymes (e.g., glutathione peroxidases, catalase and superoxide dismutases, thioredoxin reductase, and heme oxygenase) and a host of nonenzymatic components (some metals, glutathione, thiols, certain vitamins, and phytochemicals including flavonoids and other phenolics). Many of these components can be influenced by dietary patterns and behaviors.