How do antioxidants combat free radicals?

Dariush Mozaffarian, MD
Internal Medicine
Antioxidant is a catchall term for any compound that can counteract unstable molecules such as free radicals that damage deoxyribonucleic acid (DNA), cell membranes, and other parts of cells. Free radicals are a natural byproduct of energy metabolism and are also generated by ultraviolet rays, tobacco smoke, and air pollution. They lack a full complement of electrons, which makes them unstable, so they steal electrons from other molecules, damaging those molecules in the process.

Antioxidants are able to neutralize marauders such as free radicals by giving up some of their own electrons. When a vitamin C or E molecule makes this sacrifice, it may allow a crucial protein, gene, or cell membrane to escape damage. This helps break a chain reaction that can affect many other cells. It is important to recognize that the term "antioxidant" reflects a chemical property rather than a specific nutritional property. Each of the nutrients that has antioxidant properties also has numerous other aspects and should be considered individually. The context is also important -- in some settings vitamin C is an antioxidant, and in others it can be a pro-oxidant.
Dr. Rovenia Brock, PhD
Nutrition & Dietetics
Antioxidants fight free radicals, which damage the cells and tissues of your body. Free radicals are unstable molecules formed as part of the body's normal metabolic processes when the cells use oxygen to produce energy. They are unstable because they are missing an electron. Once the free radicals form, they attempt to become stable by attaching to electrons from other molecules, causing those molecules to become unstable in turn. This sparks a chain reaction that can cause major cell damage and lead to life-threatening diseases.

Antioxidants stop this process because they don't become unstable when a free radical steals one of their electrons. Instead, they act as a built-in repair system, bringing stability to instability. You can think of them as the body's natural protection against the aging and disease processes caused by free radicals.
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.