Free radicals are unstable molecules that are known to cause damage to the human body. Damage caused by free radicals is believed to lead to certain types of cancer. Antioxidants are substances that can bond with and stabilize free radicals helping to prevent the damage they cause to the body, thereby reducing the risk of cancer.
According to the National Cancer Institute (NCI) several far-reaching clinical studies were published between 1993 and 1999 regarding the effects of antioxidants on the development of cancer. These trials reached different conclusions, in part because different groups were used for the different studies. Results ranged from showing a significant reduction in the incidence of gastric cancer to a significant increase in the incidence of lung cancer. The NCI noted that results from more recent studies have been inconsistent and inconclusive.
Free radical molecules do not have a complete electron shell which makes them more likely to react chemically to nearby molecules which can cause damage to the adjoining cells. One of the most common free radicals encountered by humans is oxygen. The oxygen molecule becomes radicalized when it become electrically charged. Antioxidants neutralize the electrical charge of free radicals thereby eliminating their propensity to steal electrons from other molecules.
Antioxidants are obtained by humans through the consumption of certain foods. Fresh fruits and vegetables are the primary source of antioxidants. Nuts and grains are also a good source of antioxidants and some meats, poultry and fish can provide antioxidants to the system.
Beta-carotene can be found in raw foods that are typically orange such as cantaloupe. It is also found is some green, leafy vegetables like spinach. Lutein is found in green, leafy vegetables like collard greens and kale. Lycopene is found in tomatoes and other foods. Selenium, while not an antioxidant, is a component of antioxidant enzymes. Selenium can be obtained from grains such as rice and wheat. Vitamin A is found in liver, milk and egg yolks. Vitamin C is abundant in many fruits and vegetables including citrus fruits such as oranges and lemons. Vitamin E is found in nuts, broccoli and oils such as safflower and corn oil.
Because the data is incomplete the American Heart Association (AHA) currently does not endorse the taking of antioxidant vitamin supplements. Instead the AHA recommends a diet of nutrient-rich foods based on the basic food groups. A diet that is rich in the original food sources of antioxidants, such as fresh fruits, vegetables, whole grains and nuts, and avoiding foods that are high in saturated fat, trans fat and cholesterol will provide the consumer with sufficient antioxidants naturally without the need for supplementation.