The Longevity Dialogues

		Part 1: What is Oxidative Damage?
		If you haven't heard about antioxidants, you've probably been living in a cave. Most of us are taking at least one antioxidant supplement a day. Almost every health magazine, health show on television, or health newsletter regularly features a story about the benefits of antioxidants. We need oxygen to live, yet we can't live without it. We breathe oxygen so that our cells can produce the energy that runs all the chemical reactions that sustain life. Yet during this critical process of metabolizing oxygen, our bodies produce dangerous molecules: the superoxide molecule as well as other free radicals. These free radicals react with cell membranes, proteins and DNA to cause irreversible damage. If you wish to see oxidative damage in action, watch what happens to a cut apple exposed to air; the exposed surface oxidizes and turns brown. When untreated iron oxidizes, rust accumulates on its surface. Our bodies don't turn brown or rust, but oxidation of molecules in our cells may cause several important diseases and be a major contributor to aging.

In addition to our body's natural oxidation, we are exposed to oxidation through the smoke we breathe from cigarettes, cigars, pipes and factories. Some of this damage can be reversed by the administration of supplementary antioxidants [1]

Diabetics deplete antioxidants faster than those without this disease and therefore have greater needs for antioxidant protection [2]. You may also be getting oxidants in your diet, particularly if you are taking multivitamin supplements that contain iron and copper. Another source of free radicals is alcohol. So while a drink or two may help protect your heart, alcohol abusers can expose their bodies to severe oxidative stress.

Antioxidants can stop free radical reactions.

There are three phases of free radical action: initiation, which features the creation of free radicals; propagation, in which free radicals can produce other free radicals; and termination, in which free radicals react with themselves or other compounds to end the propagation of these molecules.

Two vitamins, C and E can terminate the propagation of free radicals and thus can protect cells from free radical damage. In addition to these vitamins, the body also has evolved natural defenses against the actions of free radicals. One of these is a protein, superoxide dismutase, an enzyme that converts the superoxide radical to hydrogen peroxide, which is in turn metabolized by another enzyme, catalase, to produce harmless water and oxygen. The importance of superoxide dismutase is reflected by the high concentration of this protein in human cells. (While superoxide dismutase pills are sold for antioxidant protection, this protein, like all proteins, is digested in the intestine and therefore never reaches the real target of antioxidants, the bloodstream and peripheral tissues.)

However, despite the large amounts of these efficient enzymes in human cells, the actions of free radicals, which are instantaneous, still cause damage before they are neutralized. Furthermore, the efficiency of these enzymes is reduced with aging, leading to the accumulation of free radical damage. Therefore, we need to optimize our body's antioxidant defenses.

Information provided in this article is for informational purposes and is not meant to substitute for the advice furnished by your own physician or other medical professional. This content should not be utilized for diagnosing or treating a health problem or disease, or prescribing any medication. Before taking any health product, you should read carefully all product packaging. If you have or suspect that you have a medical problem, promptly contact your health care provider. Information and statements regarding dietary supplements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease.

Footnotes
[1] Protective Effects of Vitamins C and E on the Number of Micronuclei in Lymphocytes in Smokers and their Role in Ascorbate Free Radical Formation in Plasma, M. Schneider, K. Diemer, K. Engelhart , H. Zankl, WE. Trommer , HK. Biesalski, Free Radic Res , 2001, vol. 34, pp. 209--19
[2] Increased accumulation of the glycoxidation product N(epsilon)-(carboxymethyl)lysine in human tissues in diabetes and aging ED. Schleicher, E. Wagner, AG. Nerlich, Journal of Clinical Investigation, 1997, vol. 99, pp. 457--68

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