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What are Antioxidants?

Category: Patient Stories
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Bowl of Blueberries "Antioxidants are substances that protect cells from unstable molecules called free radicals," says Karen Johnson, RD, LD, dietitian at St. Luke's. "This is a naturally occurring process. The unstable molecules are missing a part, so the antioxidants can fill in the piece and make it whole, so there's no damage."

What is the Benefit of Antioxidants?

According to the National Cancer Institute, free radical damage may lead to cancer, especially if there is exposure to environmental factors such as tobacco smoke or radiation. And while research is inconclusive as to whether antioxidants prevent cancer, antioxidants do help lower the risk of other chronic diseases. "Good nutrition includes a diet full of foods with antioxidants," says Johnson. "Each food with antioxidants has a different benefit. There is no one 'super food' that contains all the antioxidants the body needs."

Which Foods are Rich in Antioxidants?

According to Johnson, eating a variety of fruits, vegetables, nuts and beans will provide the antioxidants you need. "Be careful about antioxidant supplements," says Johnson. "Some can be harmful. When taken out of their natural context in food, the benefits don't pan out. But the good news is, foods that are high in antioxidants are tasty. It's not hard to include these foods because they taste good, and they have flavors and textures that add to your meal."

One source of antioxidants is a mineral called selenium. Selenium is an essential trace mineral, meaning you get it from the foods you eat. In the United States, selenium is found in the protein of animals that eat grains or plants grown in soil that is rich in selenium. Grains such as rice and wheat are also good sources of selenium.

Johnson has advice on how to know you are getting a good range of antioxidants. "Antioxidant foods have good color. Eat a colorful plate, and you'll get a good variety that provides the antioxidants you need."



Beta carotene

Often orange or green in color, such as sweet potatoes, carrots, cantaloupe, squash, apricots, pumpkins, collard greens, spinach, kale


Collard greens, spinach, kale


Tomatoes, watermelon, guava, papaya, apricots, pink grapefruit

Vitamin A

Liver, sweet potatoes, carrots, milk, egg yolk, mozzarella cheese

Vitamin C

Fruits, vegetables, some cereals, beef, poultry and fish

Vitamin E

Almonds, mangos, nuts, broccoli and oils such as wheat germ, safflower, corn and soybean

*National Cancer Institute Antioxidants and Cancer Prevention Fact Sheet