Antioxidants are substances, either natural or manufactured, that may prevent or limit cell damage caused by unstable particles called free radicals. Antioxidants work by neutralizing free radicals -- giving them electrons. Antioxidants may also be able to undo some cell damage.[1,2,4]
Types of antioxidants
Vitamin A, vitamin C, vitamin E, selenium, lycopene, and beta-carotene are examples of antioxidants.
Free radicals
Free radicals are groups of atoms that are produced when oxygen interacts with certain molecules, thereby setting off a chain reaction. Their primary danger comes from the damage caused when they react with DNA, and other cell components. Cells can die off, or stop functioning correctly, when this occurs. Antioxidants are the body's defense system against free radical damage.
Free radicals can be formed by:
- Sun exposure
- Cigarette smoke
- Alcohol consumption
- Air pollution
- Exercise
- Inflammation
- Drug abuse
Cells damaged by free radicals may be at risk for developing cancer, heart disease, and diabetes.[1]
Sources
Antioxidant Food Sources
The body makes some antioxidants and gets others from food to combat free radicals.[4] It's important to eat a well-balanced diet to help you get the antioxidants you need.
Good sources of antioxidants
| Category | Examples |
|---|---|
| Fruit | Strawberries, oranges, cantaloupe, watermelon |
| Vegetables | Broccoli, tomatoes, kale, carrots |
| Dairy | Milk, butter, eggs |
| Meat | Fish, chicken, beef, turkey |
| Legumes and oils | Nuts, seeds, oils, sunflower seeds, almonds, peanuts, corn oil |
| Carbohydrates | Bread and pasta |
| Cereals | Whole wheat, rice, corn |
Supplements can also be a good source of antioxidants.
Do antioxidants work
Antioxidants: Selenium
Many well-organized studies, involving numerous subjects, have looked at the effect of antioxidant supplements on diseases, such as cardiovascular disease, cancer, and cataract prevention.They found that overall, antioxidants are not beneficial.[2]
But, the Age-Related Eye Disease Study (AREDS), led by the National Eye Institute and co-sponsored by the National Institutes of Health, found that antioxidant supplementation could be beneficial. Researchers discovered that a combination of antioxidants (vitamin C, vitamin E, and beta-carotene) and zinc significantly reduced the risk of developing advanced-stage, age-related macular degeneration (ARMD) for people who had intermediate stage (ARMD) and advanced stage in only one eye.
However, the use of antioxidants without zinc was less effective and the antioxidants didn't effect cataract development.[2, 4]
More research is being done to discover antioxidants' effects on Alzheimer's disease, breast, and prostate cancers.[2]
Each antioxidant is different, so getting one or two types is not enough. They work together to provide better all-round health. That's why healthy eating, including a variety of fruits and vegetables, whole grains, and healthy fats from nuts, seeds, and oils, still beats supplements -- even in high doses -- in helping to prevent disease.[2]
Drug interactions
Antioxidants may interact with some medications, potentially altering their effects. Do not take vitamin E if you are on blood thinners as they may cause bleeding. Ask your doctor before taking antioxidants if you are undergoing cancer treatment.[2]
Safety issues and other considerations
References
FamilyDoctor.org;"Antioxidants: What You Need to Know;" 2010
National Center for Complementary and Alternative Medicine;"Antioxidants and Health: An Introduction;" Get the Facts; National Institutes of Health;" Updated 2012
National Cancer Institute;"Antioxidants and Cancer Prevention Fact Sheet"
Harvard School of Public Health; "Antioxidants: Beyond the Hype"
Rice; "Antioxidants and Free Radicals; Updated 1996
