Updated September 22, 2014.

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Antioxidants and Cancer Prevention

We often hear the word antioxidant in magazines, in the news, and even on the labels of ketchup bottles! What are exactly are antioxidants and can they effectively prevent or slow down cancer?

In order to understand antioxidants and cancer prevention, we must know what exactly antioxidants are and how they help our bodies.

Antioxidants are substances that prevent damage to cells caused by free radicals.

Free radicals are molecules that have an unpaired electron, which creates the said molecule to become unstable. These free radicals can either accept an electron from or donate an electron to another molecule, thus, free radicals behaving as oxidants or reductants, respectively.  Free radicals attack important molecules inside a cell, such as DNA, proteins, and lipids, and this may lead to the possible development of cancer.

Antioxidants search for these free radicals and lend them an electron. This stabilizes the molecule, thus preventing damage to other cells. Antioxidants also turn free radicals into waste by products, and they eventually get eliminated from the body. They also have the ability to repair previous damage to cells.

What Factors Cause Free Radicals To Form

The following are some of the causes of free radicals: cigarette smoke, pollution, radiation (such exposure to UV light), processed foods, charred food, stress, drugs all cause the formation of free radicals. Other factors include normal daily processes like food digestion and breathing.

Where Can I Find Antioxidants?

Antioxidants are found naturally in fruits and vegetables. They also are contained in some meats. Some examples of fruits and veggies that are rich in antioxidants are:

• Yellow and orange vegetables- Think sweet potatoes, carrots, pumpkin, papaya, guava, and cantaloupe
• Green and leafy veggies, like turnip greens, spinach and kale
• Other great fruits include strawberries, kiwi, cranberries, and plums
• Great veggies for antioxidants are broccoli, red and green peppers, bok choi, and tomatoes

Take caution in overdoing it with antioxidants- there is such a thing as over-supplementing yourself! Talk to your physician about what foods and amount fit your personal health needs best and are safe!

Studies Have Shown...

According to the National Cancer Institute "considerable laboratory evidence from chemical, cell culture, and animal studies indicates that antioxidants may slow or possibly prevent cancer. However, information from recent clinical trials is less clear. In recent years, large-scale, randomized clinical trials reached inconsistent conclusions."