Understanding Free Radicals and Antioxidants
The Role of Antioxidant Vitamins in Preventing Disease
Jun 21, 2009
Free radicals are atoms or groups of atoms containing unpaired electrons. Since electrons want to be paired, a free radical is highly unstable, and strives to "steal" an electron from another atom in order to stabilize itself. The second atom then becomes a free radical itself, which begins a chain reaction of electron stealing which continues until something interrupts the process.
Sources of Free Radicals
Free radicals are formed during a process called oxidation, which is a reaction between oxygen molecules and the molecules of another substance. Oxidation is the process by which cars rust, apples turn brown, and the Statue of Liberty gets her green tint.
Humans encounter free radicals in the environment through smoking and exposure to radiation and pollution. Free radicals are also produced naturally in the body through the break-down of food.
How Free Radicals Cause Damage
Once the chain reaction of electron swapping begins, damage can occur to cell structures and DNA. Over time, this damage becomes irreversible and can lead to heart disease, cancer, or other diseases, according to the Medline Plus health topic Antioxidants.
Antioxidants Help Prevent Damage from Free Radical Exposure
The human body does a good job of keeping free radicals in check through the use of antioxidants. Common antioxidants include the vitamins A, C, E, and Beta-Carotene, the mineral selenium, and plant pigments such as lutein. These substances and others have the effect of stopping the free radical chain reaction.
Since the human body cannot produce these substances, they must be supplied in the diet. Foods rich in antioxidants are nuts and seeds (vitamin E), citrus fruits and green vegetables (vitamin C), liver, eggs, and orange colored fruits and vegetables (vitamin A and beta-carotene) and dark green, leafy vegetables such as spinach and kale (lutein).
Healthy Eating and Antioxidant Supplement Recommendations
Free radicals and the damage they cause cannot be completely avoided, but the damage can be minimized by eating a balanced diet rich in antioxidants. The American Heart Association and the American Cancer Society both suggest at least five servings of fruits and vegetables daily, in accordance with the USDA dietary guidelines. Care should be taken to eat a wide variety of foods to ensure proper nutrition.
Neither recommend taking antioxidant supplements either in place of or in addition to eating a variety of fruits and vegetables, stating that there is not enough scientific evidence to suggest that taking supplements is effective. The American Heart Association further states that some studies have suggested the use of antioxidant supplements may be harmful.
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