What's wrong with oxidation, anyway?
Oxidation and Antioxidants in Depth

Isn't oxidation a vital biological process? Isn't oxidation the means of supplying power to all our organs and muscles? Isn't oxidation of sugars and carbohydrates the primary way we turn food into energy?

Yes, yes, and yes. But despite the fact that oxidation is one of the most fundamental and necessary biochemical reactions, not all oxidation is desirable. In fact, oxidation of the wrong substances at the wrong time can have a devastating effect on our health.

Consider the operation of a cell membrane, for example. The cell membrane controls everything that goes in and out of every cell in your body. It is a mechanical barrier, yet it must be a "smart" barrier that is selectively permeable. The cell membrane must also "work," pushing required substances in and pulling toxic products out, even if these substances have a natural tendency to pass through the membrane in the other direction. The cell membrane works with a wonderfully elaborate communications system within the cell, controlling the entry of parasites, the identification of dangerous viruses, and other immune function responses. And it does all this without a single bit or byte of programming logic. It's all contained in the chemical logic of thousands of specialized enzymes, proteins and fats.

The chemical structure of many of these substances that control cell processes is not very far removed from the nutrients that are "burned" or oxidized for energy. After all, the food we eat is itself made of cells. Our vital cell-control chemicals can be oxidized too, either by dissolved oxygen or by other chemicals that have essentially the same effect as oxygen. Sure, we need energy, but we also need to be careful what we burn to get it! We don't want to burn the furniture to heat the house. Or, to use an analogy closer to DNA damage, we don't want to burn the instructions for operating the furnace in order to light the logs in the fireplace. So how do we avoid these biological disasters? Our bodies are equipped with natural antioxidants, chemicals that protect delicate and unstable molecules from being "thrown into the fire."

When a long and elaborate molecule is broken apart by oxidation, it usually releases a new molecule called a "free radical." Free because it is not bonded to another molecule, and radical to indicate, in the sometimes obscure language of chemistry, that it is electrically charged. This charged particle in turn can oxidize other molecules in a kind of chain reaction, with the result that the initiation of only one oxidation event destroys the function of a very large number of molecules of some substance that was supposed to do something else - like possibly identify and block the intrusion of a virus into the cell nucleus, or maybe control the regeneration of skin tissue, or perhaps repair damage to an artery wall. Oxidation throws a large monkey wrench into a very complicated machine. This makes oxidation damage especially devastating - One single oxidation event can start the chain reaction, and a vital process is compromised.

Time for a question: "How can a charged particle cause oxidation? Don't you need more oxygen?" Very good, I'm glad you asked that.

The answer is, "not really." Oxidation, in the strictly defined sense as used by chemists, is simply a reaction that results in removal of electrons from a molecule, leaving the particle with a net positive charge. (Electrons, the tiny bits of electrical charge that circle each atom in a strange kind of "orbit," have a negative charge. The nucleus, the center of the atom, has a positive charge. So if an electron is pulled away, the net charge remaining is positive.) Oxygen, because of its strong propensity to attract two additional electrons in molecular bonds, is thought of as the most common and one of the strongest oxidizing agents. But other reactive substances, like the infinite variety of free radicals produced by the oxidation of many biological substances, can do the same work.

Aside from breaking apart complicated organic molecules and membranes and rendering enzymes inoperable, oxidation can also damage fatty acids by filling in the "unsaturated" locations in the chain of atoms that make up these vital substances. In other words, a "polyunsaturated" fat my become partially saturated through an oxidation process (actually peroxidations, because an OH particle is added instead of oxygen alone). The problem here is that altered fat changes its shape in unnatural ways - in general it becomes too thick and easily solidified. Food processing companies use this property to their advantage, to engineer melting point and "mouth feel" of food products (hence the ubiquitous "partially hydrogenated vegetable oil" on the ingredients label of so many less-than-healthful foods). These substance may fool your biochemistry into using them in initial phases of all kinds of biological process - from immunity to synthesis of sex hormones. But you can't fool all of your body all of the time! The result is a serious compromise of your most delicate health-sustaining machinery.

Cross-linking is another possible result of oxidation. Long protein molecules that make up your skin, tendons, and arteries sometimes bond to each other in undesirable ways after oxidation damage. The immediate result is usually a significant loss of flexibility and elasticity. The long-term result is wrinkled skin, stiff joints, and sick arteries.

There are many real-life examples of oxidation that you can hold in your hand. Think of plastic that has become brittle and powdery by age and sunlight, the long chains of hydrocarbon molecules having been broken up by the oxidation process. Or an old rubber band that has lost all it's elasticity and strength, the rubber molecules now stuck together. Or those white athletic socks, washed with too much bleach (a powerful oxidizing agent). The long fibers of cotton are broken apart by oxidation. The result? The socks tear to pieces when you try to slide them on your feet.

These are examples of changes in chemical structure due to oxidation that we can see and feel. The changes that occur with our own chemistry would be just as apparent to us if we could hold our cell membranes in our hands, or observe the purity of our enzymes.

Antioxidants, then, have a critical role to play. They occur naturally in almost every living organism, but a number of environmental and social factors conspire to place most of us in a very difficult biochemical situation. We are subjected to far higher exposure to toxic oxidizers (food additives, drugs, pesticides, synthetic hormones in food, pollution, radiation) and at the same time have greatly reduced access to natural antioxidants (vitamin E, vitamin C, carotene, and a host of other less well-known chemicals).

Although arguments have been made that synthetic antioxidants put into food products as preservatives (BHT, for example) can fill this shortfall, the consensus among researchers is that the artificial preservatives do far more harm than good. Conclusion? Unless you are willing to move to the mountains, eat all your food fresh-picked or fresh- killed, and cook very little of it, you need to supplement the supply of antioxidants to your body.

There are many forms that this supplementation can take. Some foods, especially those considered to have adaptogenic properties, are high in natural antioxidants. (By "adaptogenic" we mean a food substance that has the ability to activate natural healing or immune responses, and thus bypass the negative side effects of artificial drugs. Adaptogenic nutrients also seem to able to find the action sites where they are needed, without interfering with other physiological systems.) To be practical, though, the higher concentrations found in specialized oils or dry capsule supplements are usually preferred. But beware - most oil-based supplements require extremely careful packaging and handling to maintain full potency and freshness.

There's a paradox here: If vitamin E is such a good antioxidant, why is it that oils with lots of vitamin E can become rancid so easily? Shouldn't an oil containing large amounts of an antioxidant be almost immune to oxidation?

The answer to this seemingly paradoxical question is to be found in the method by which most antioxidants function: What they really do is provide an alternative oxidation path. An antioxidant will react with free radicals more easily than the substances it is there to protect, thereby intercepting the oxidation chain reaction. So it's not surprising that a rich antioxidant-laden oil has to be treated with very special care. It's a strong argument for choosing dry antioxidant supplements over oil-based products.

Oxidative damage, and antioxidant deficiency, are now beginning to be recognized as important factors in a very wide range of human diseases, from cancer to viral infections to circulatory disease. And it's probably the primary reason why our bodies eventually run out of new cells to replace the older ones that eventually fail.

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Copyright © 2000 Betty Kamen by Nutrition Encounter, Novato, CA 94948
These documents are provided for information only and should not be considered to be medical advice.