Anti-oxidants are defined as a substance that inhibits oxidation, especially one used to counteract the deterioration of stored food products. Antioxidants are man-made or natural substances that may prevent or delay some types of cell damage. Antioxidants are found in many foods, including fruits and vegetables. They are also available as dietary supplements. Examples of antioxidants include vitamin A, C, E, selenium, lycopene, lutein, and beta-carotene. Vegetables and fruits are rich sources of antioxidants. There is good evidence that eating a diet with lots of vegetables and fruits is healthy and lowers risks of certain diseases, but it isn't clear whether this is because of the antioxidants, something else in the foods, or other factors. Doctors recommend eating balanced diets that include fresh fruits and vegetables. A lot of produce has natural antioxidants. It also contains minerals, fiber, and other vitamins. Eating healthy can help lower your risk of certain diseases. However, antioxidants alone do not prevent chronic conditions. In fact, high-dose supplements of antioxidants may be linked to health risks in some cases. For example, high doses of beta-carotene may increase the risk of lung cancer in smokers. High doses of vitamin E may increase risks of prostate cancer and one type of stroke. Antioxidant supplements may also interact with some medicines. Some people choose to take antioxidant supplements. However, many are not balanced. They are also not FDA approved or regulated. This means that the ingredients and suggested dose listed on the bottle may not be correct. Rigorous scientific studies involving more than 100,000 people combined have tested whether antioxidant supplements can help prevent chronic diseases, such as cardiovascular diseases, cancer, and cataracts. In most instances, antioxidants did not reduce the risks of developing these diseases. Concerns have not been raised about the safety of antioxidants in food. However, high-dose supplements of antioxidants may be linked to health risks in some cases. Supplementing with high doses of beta-carotene may increase the risk of lung cancer in smokers. Supplementing with high doses of vitamin E may increase risks of prostate cancer and one type of stroke. Researchers have also studied antioxidants in laboratory experiments. These experiments showed that antioxidants interacted with free radicals and stabilized them, thus preventing the free radicals from causing cell damage. The Women’s Health Study, which included almost 40,000 healthy women at least 45 years of age, found that vitamin E supplements did not reduce the risk of heart attack, stroke, cancer, age-related macular degeneration, or cataracts. Although vitamin E supplements were associated with fewer deaths from cardiovascular causes, they did not reduce the overall death rate of study participants. Do not use antioxidant supplements to replace a healthy diet or conventional medical care, or as a reason to postpone seeing a health care provider about a medical problem.