Antioxidant
Quick Definition
A molecule that inhibits the oxidation of other molecules, protecting cells from damage caused by free radicals.
In-Depth Explanation
Antioxidants are compounds that neutralize free radicals -- unstable molecules that can damage cells through a process called oxidative stress. This cellular damage has been linked to aging, heart disease, cancer, and other chronic conditions.
The body produces some antioxidants naturally (endogenous), while others come from food (exogenous). Key dietary antioxidants include vitamin C, vitamin E, beta-carotene, selenium, and polyphenols found in fruits, vegetables, nuts, and whole grains.
Foods particularly rich in antioxidants include blueberries, dark chocolate, pecans, artichokes, and kidney beans. The ORAC (Oxygen Radical Absorbance Capacity) scale was once used to measure antioxidant capacity, though the USDA withdrew its database in 2012 due to misuse in marketing.