Antioxidants

Other name(s):

free radical scavengers

General description

Antioxidants help prevent free radicals from damaging the body by neutralizing them.

A free radical is an atom or molecule that contains one or more unpaired electrons. These unpaired electrons want to bond to atoms or molecules and do so easily. The body is damaged during this bonding process. Individuals are exposed to many things that will create free radicals such as radiation, environmental toxins, and tobacco smoke. The body also generates free radicals when it converts fat to energy.

Antioxidants come in many forms including enzymes, vitamins, and minerals. Below is a partial list.

Enzymes:

• Catalase

• Coenzyme Q-10

• Glutathione peroxidase

• Methionine reductase

• Superoxide dismutase (SOD)

Vitamins:

• Beta-carotene

• Vitamin A

• Vitamin C

• Vitamin E

Minerals (these are not antioxidants on their own, but work with oxidative enzymes):

• Selenium

• Zinc

Herbs:

• Bilberry

• Ginkgo biloba

• Grape seed extract

• Green tea extract

Others:

• Anthocyanidins

• Carotenoids

• Flavonoids

• Resveratrol

• Lutein

• Lycopene

Medically valid uses

Antioxidants have been studied to evaluate their impact on cancer, cancer prevention, heart disease, arthritis, and diseases associated with aging such as macular degeneration. The results of these studies have been mixed.  Some studies have shown an increase in lung cancer among smokers who took beta carotene. Another recent study showed that selenium  and vitamin E supplements did not decrease the risk of prostate cancer, and that men taking vitamin E alone had an increased risk of prostate cancer. It is not known if taking synthetic antioxidant supplements have the same effect on the body as eating foods rich in these substances. The Women's Antioxidant Cardiovascular Study (studying women 45 years and older) found that vitamin C, vitamin E, or beta-carotene had no beneficial effect on preventing heart disease or stroke in women under 65, but it did decrease risk in women 65 and older. 

Antioxidants, especially vitamin C, vitamin E , and carotenoids, may delay the onset of macular degeneration. Macular degeneration is an eye disease and a leading cause of blindness in individuals over age 65. The macula is the portion of the retina responsible for our sharpest and most acute vision.

Antioxidants interfere with these disease processes by stopping free radicals.

Unsubstantiated claims

Please note that this section reports on claims that have NOT yet been substantiated through scientific studies.

Researchers agree that antioxidants from fruits and vegetables do reduce the risk for many diseases and affect the onset of age-related illnesses. However, evidence concerning the intake of antioxidants from supplements has not been conclusive. The benefit of taking antioxidants derived from supplements varies among studies.

Dosing

Antioxidants come in a variety of forms and dosages. Consult the package label and your physician for guidelines.

Women who are pregnant or breastfeeding should consult a physician before taking any dietary supplements.

Side effects, toxicity, and interactions

The side effects of antioxidants vary, depending on the individual antioxidant.

There are no significant food or drug interactions associated with antioxidants.