Free radicals, especially reactive oxygen species like superoxide, hydroxyl, and perhydroxyl, can damage DNA, lipids, and proteins. This radical damage can lead to inheritable mutations, cancer, autoimmune diseases, and atherosclerosis. Sources of free radicals include ionizing radiation, transition metal ions, nitric oxide, the respiratory burst in immune cells, and mitochondrial electron transport. However, the body protects itself against radical damage through antioxidants like superoxide dismutase, catalase, glutathione peroxidase, vitamins C and E, and polyphenols; these antioxidants trap radicals in a stable form. At high concentrations, some antioxidants like vitamin C, vitamin E, and beta-carotene can also act