Nowadays you can't read or hear anything related to health without coming across the term "antioxidant." Almost every new product is in some way touted for its beneficial antioxidant properties. However, this claim raises many questions. What really is an antioxidant? Are antioxidants truly related to health benefits? Do I need more antioxidants? While the subject of antioxidants is extensive, considering a few of these basic questions can help you determine just what role antioxidants have in providing you with significant health benefits.

What are free radicals?

First we need to understand a few important chemical processes. Key to an understanding of antioxidants is the concept of "free radicals." Technically speaking, a free radical can be defined as "any chemical species capable of existence that contains one or more unpaired electrons." Simply speaking, all molecules are composed of atoms and all atoms have a nucleus around which electrons orbit. Due to various energetic principles, these electrons generally orbit their respective nuclei in pairs. However, various circumstances can cause a molecule to either loose an electron, or gain an extra electron. The result is a molecule with an unpaired electron. A molecule with an unpaired electron is considered a free radical. Because the free radical state is by definition unbalanced (extra or missing electrons), the free radical is highly reactive, meaning it will try to combine with other molecules to "steal" an electron and return to a stable state. This, of course, makes the molecule that has lost an electron a free radical as well. So, this newly formed free radical must regain its lost electron from another molecule, in turn creating yet another free radical. This becomes a self-perpetuating process, as each time a free radical attacks a molecule, a new free radical is formed.

Where do free radicals come from?

Essential to understanding the chemistry of free radicals is the role played by oxygen. The simple act of breathing in oxygen to produce ATP (energy molecules) for use in our metabolism results in the production of free radicals. So, one source of free radical production is the oxidative metabolism involved in the body's production of energy. A second source of free radicals is found in certain types of white blood cells (phagocytic cells). These cells are responsible in part for destroying unwanted microbes and other infectious invaders. One way in which these cells achieve their destructive ability is by the production of free radicals. This demonstrates both the dangerous power of free radicals as well as their practical utility within the body.

Free radicals are also a result of enzymatic production. Enzymes that comprise the cytochrome P450 system (enzymes involved in various oxidative reactions including drug detoxification) produce free radicals as a by-product. Additionally, the activity of the enzyme xanthine oxidase can result in the production of free radicals that are in part involved in the tissue damage that occurs during surgery that involves ischemia followed by reperfusion. Finally, sources as simple as cigarette smoke and sunlight can also result in the formation of free radicals.

Are free radicals harmful?

Excessive production of free radicals can cause damage. Fats, proteins, carbohydrates, and DNA are all subject to free radical damage. Once damaged, a tissue may no longer function properly. For example, membranes lose their ability to properly transport nutrients, lipoproteins particles (composed of both fat and protein) become altered and more atherogenic, and damaged DNA can lead to potential mutations. Free radical damage is associated with almost every disease, including arthritis, heart disease, cancer, cataract, Alzheimer's, and Parkinson's. What remains unclear is the degree to which free radical production precipitates or results from the disease pathology.