Antioxidants and Free Radicals

Oxygen is essential to life, since humans need to breathe air containing oxygen in order to sustain life. Yet oxygen is very active and combines readily with many compounds in our body. Some of these compounds can cause damage.

During cellular respiration (the process that creates energy), some oxygen molecules are converted into oxidizing agents (also called “free radicals”), such as superoxides or hydrogen peroxide. These molecules are unstable and react with other compounds in an effort to become stabilized. This quest for stability can be quite damaging to normal body tissues, but fortunately the body is equipped with an “antioxidant” defense system.

Environmental sources of free radicals: The environment is a source of free radicals. Such oxidizing agents include: ionizing radiation—(from industry, sun exposure, cosmic rays, and medical X-rays); ozone and nitrous oxide—(primarily from automobile exhaust); heavy metals—(such as mercury, cadmium, and lead); cigarette smoke—(both active and passive); alcohol; unsaturated fat—(may create a strain on the natural antioxidants of the body); and other chemicals and compounds from food, water, and air.

When these free radicals enter the body, they can react with healthy tissue, setting off potentially damaging reactions. Free radicals are believed to play a role in more than sixty different health conditions, including the aging process, cancer, and atherosclerosis.¹ Reducing exposure to free radicals and increasing intake of antioxidant nutrients can reduce the risk of free radical-related health problems.

Natural antioxidants: Free radicals are inherently unstable, since they contain “extra” energy. To reduce their energy load, free radicals react with certain cells in the body, interfering with the cells’ ability to function normally. Fortunately there are many natural antioxidants that interfere with free radicals before they can damage the body. Antioxidants work in several ways: they may reduce the energy of the free radical, stop the free radical from forming in the first place, or interrupt an oxidizing chain reaction to minimize the damage of free radicals.

Superoxide dismutase (SOD), catalase, and glutathione peroxidase are enzymes produced by the body itself to defuse many types of free radicals. Supplements of these compounds are also available to augment the body’s supply. However, these antioxidant enzymes may not absorb well. It may be more effective to take the “building blocks” the body requires to make SOD, catalase, and glutathione peroxidase. These building block nutrients include the minerals manganese, zinc, and copper for SOD and selenium for glutathioine peroxidase.

In addition to enzymes, many vitamins and minerals act as antioxidants in their own right, such as vitamin C, vitamin E, beta-carotene, lutein, lycopene, vitamin B3 in the form of niacin, vitamin B2, vitamin B6, coenzyme Q10, and cysteine (an amino acid). Herbs, such as bilberry, turmeric (curcumin), grape seed or pine bark extracts, and ginkgo biloba can also provide powerful antioxidant protection for the body.

A wide variety of antioxidant enzymes, vitamins, minerals, and herbs may be the best way to provide the body with the most complete protection against free radical damage. See the individual nutrient or herb entries in HealthNotes Online for more information on a particular antioxidant.

References:

1. Ames BN, Shigenaga MK,  Hagen TM. Oxidants, antioxidants, and the degenerative diseases of aging. Proc Natl Acad Sci USA 1993;90:7915-7922.

 

Copyright © 1998 Virtual Health, LLC

The information presented in HealthNotes Online is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your physician, nutritionally-oriented health care practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.