Antioxidants: What You Need to Know

What are antioxidants?

The cells in your body are exposed to oxygen every day. Oxygen is important for your body’s health, but exposure to oxygen also causes oxidation. In oxidation, body chemicals are altered and become what are known as free radicals. Exposure to environmental factors, such as sun exposure, cigarette smoke, alcohol and pollution, also creates free radicals.

Over time, free radicals can cause a chain reaction in your body that damages important body chemicals, DNA and parts of your cells. Some cells can heal, while others are permanently damaged. Scientists believe free radicals may contribute to the aging process as well as diseases like cancer, diabetes and heart disease.

Antioxidants are natural substances that may stop or limit the damage caused by free radicals. Your body uses antioxidants to stabilize the free radicals. This keeps them from causing damage to other cells. Antioxidants can protect and reverse the damage caused by oxidation to some extent.

Where are antioxidants found?

Your body produces some antioxidants to fight off the free radicals formed by normal body processes. Your body can also get antioxidants by eating a healthy diet. Examples of antioxidant-rich foods include fruits and vegetables that are high in nutrients such as vitamins A, C and E, beta-carotene, lutein, lycopene and selenium.

Some people choose to take antioxidant supplements. Talk to your doctor if you are considering adding a supplement to your diet. Many supplements do not contain a balance of vitamins, minerals and enzymes and can actually have a negative effect on your health.

What foods are good sources of antioxidants?

To get the most antioxidants, eat a diet that includes a healthy mix of colorful fruits and vegetables and other antioxidant-rich foods:

While foods that are rich in vitamin E and beta-carotene are very healthy and help reduce cancer risk, the U.S. Preventive Services Task Force and the American Academy of Family Physicians recommend against taking vitamin E or beta-carotene supplements for the prevention of cancer. People who smoke or have a high risk for lung cancer should not take supplemental beta-carotene because it can increase the risk of lung cancer.

The best way to get antioxidants is by eating a diet with lots of vegetables, fruits, whole grains, seeds and nuts. Variety is also important. If you take a multi-vitamin supplement, be careful. Too much of some nutrients from supplements rather than foods, such as vitamins E and A or selenium, can be harmful. Be sure to talk to your doctor before taking any vitamin supplements.

  • Vitamin A is found in milk, liver, butter and eggs.
  • Vitamin C is found in most fruits and vegetables. Those with the highest amounts of vitamin C include papayas, strawberries, oranges, cantaloupe and kiwi, as well as bell peppers, broccoli, Brussels sprouts, tomatoes, cauliflower and kale.
  • Vitamin E is found in some nuts and seeds, including almonds, sunflower seeds, hazelnuts and peanuts. It can also be found in green leafy vegetables, such as spinach and kale, and in oils, such as soybean, sunflower, corn and canola oils.
  • Beta-carotene is found in colorful fruits and vegetables, including carrots, peas, cantaloupe, apricots, papayas, mangoes, peaches, pumpkin, apricots, broccoli, sweet potatoes and squash. It can also be found in some leafy green vegetables, including beet greens, spinach and kale.
  • Lutein is found in green leafy vegetables, such as spinach, collards and kale, broccoli, corn, peas, papayas and oranges.
  • Lycopene is found in pink and red fruits and vegetables, such as pink grapefruit, watermelon, apricots and tomatoes.
  • Selenium is found in cereals (corn, wheat and rice), nuts, legumes, animal products (beef, fish, turkey, chicken, eggs and cheese), bread and pasta.


This content was developed with general underwriting support from Nature Made®.



  • American Dietetic Association. What Is an Antioxidant?. Accessed 05/12/10
  • Harvard School of Public Health. Antioxidants: Beyond the hype. Accessed 05/12/10
  • Medline Plus. Antioxidants. Accessed 05/12/10
  • National Cancer Institute. Antioxidants and Cancer Prevention: Fact Sheet. Accessed 05/12/10
  • Mayo Foundation for Medical Education and Research. Accessed 05/12/10
  • Cleveland Clinic. Antioxidants, Vitamin E, Beta Carotene, and cardiovascular disease. Accessed 05/12/10
  • University of California-Berkeley Wellness Guide to Dietary Supplements. Selenium. Accessed 05/12/10