What is an Antioxidant?

Antioxidants are substances or nutrients in our foods, which can prevent or slow the oxidative damage to our body.  When our body uses oxygen our cells then produce free radicals, which are by-products that can be harmful.  These free radicals can damage the body’s cells when they outnumber the antioxidants and contribute to diseases such as heart disease, macular degeneration, diabetes, and cancer.  Antioxidants counteract free radicals by preventing, as well as repairing this damage (1).

Where Antioxidants are Found?

Antioxidants can be found in many healthy foods from plants and animals such as beans, grain products, fruits and vegetables, coffee and tea, and meat and fish. Here is a list of the most familiar ones: vitamin C, vitamin E, flavonoids, beta-carotene, and other related carotenoids.  For example, foods that are bright in color such as corn, cantaloupe, mango, and butternut squash derive its yellow and orange pigments from lutein.  Foods like tomatoes and watermelon that are red contain lycopene. Lastly, anthocyanins can be found in blue/purple produce like blueberries (2).

Supplements were created as another source of antioxidants. However, some research has pointed to whole foods being more effective to aid in preventing disease than supplementation (3).  In addition, it is important to consider that high intakes of supplements could have a toxic effect on the body.

The Bottom Line

Antioxidants are substances that can prevent or repair the oxidative damage caused by free radicals. That damage can lead to diseases such as macular degeneration, diabetes, and cancer. Research has shown that it is best to consume whole foods like fruits, vegetables, and whole grains because they are all filled with networks of antioxidants.

References:

1. Antioxidants: In Depth, https://nccih.nih.gov/health/antioxidants/introduction.htm

2. Carlsen MH¹, Halvorsen BL, Holte K, et al. The total antioxidant content of more than 3100 foods, beverages, spices, herbs and supplements used worldwide. Nutr J. 2010 Jan 22;9:3. doi: 10.1186/1475-2891-9-3.

3. Lee IM¹, Cook NR, Gaziano JM, et al. Vitamin E in the primary prevention of cardiovascular disease and cancer: the Women's Health Study: a randomized controlled trial. JAMA. 2005 Jul 6;294(1):56-65.