Free Radicals and Vitamin E
By: Dr. Obikoya

Vitamin E is a fat-soluble compound (tocopherol) first recognized in 1922, was first obtained in a pure form in 1936; it was identified chemically in 1938. A number of similar compounds having vitamin E activity and called tocopherols have been isolated.

Vitamin E acts as an inhibitor of oxidation processes in body tissues. It protects unsaturated fats in the body from oxidation by peroxides and other free radicals. The possibility that vitamin E may help prolong an active life-span by slowing the rate of oxidative destruction of biological membranes is increasingly real. Vitamin E protects vitamin A and essential fatty acids from oxidation in the body cells and prevents breakdown of body tissues.

Vitamin E plays an important role in protecting the fat molecules in cell membranes and the blood. Without vitamin E, these polyunsaturated fat molecules could be damaged by the oxygen in aggressive molecules, called free radicals. This process is called oxidation and is similar to the way that butter turns rancid when it is exposed to air. Oxidized fat molecules can harm body tissues over long periods of time. Vitamin E can help protect cells from this damage and, because of this ability scientists call vitamin E an antioxidant.

The quantity of vitamin E needed by the body is related in part to the amount of polyunsaturated fat consumed. This is because polyunsaturates such as those in sunflower oil and margarine are easily oxidized. This oxidation is thought to cause chemical changes which may lead to them being deposited in the arteries. This process is involved in the formation of fatty plaques which can contribute to heart disease. If you eat a lot of these foods, you will need to take higher doses of vitamin E.

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 B12, coenzyme Q10 and cysteine, an amino acid. Consuming a wide variety of antioxidant enzymes, vitamins, and minerals may be the best way to provide the body with the most complete protection against free radical damage.

Free radicals are chemicals with an unpaired electron in the outer shell of the molecule. Free radicals are highly reactive due to the presence of this unpaired electron. Free radicals are actually a group of molecular fragments that are capable of independent existence. That they are highly reactive indicates that they have low chemical specificity, capable of reacting with most molecules around them including proteins, lipids, carbohydrates, and DNA.

Indeed, because they are trying to become stable as fast as possible, they are short-lived and wont to “attack” and capture the needed electron from the nearest stable molecule, turning the attacked molecule into a free radical in the process. Once this process begins, it becomes a dangerous chain reaction disrupting the functioning of our cells and our entire body. Free radicals therefore, play a key role causing human disease, such as cancer, and in making some drugs toxic to our body, and they have been implicated in the aging process. They may also be important in causing certain eye, brain, and mental disorders.

The radical derivatives of oxygen are the most damaging free radicals in the body. They are also known as reactive oxygen species and include oxygen in its triplet state (3O2) or singlet state (1O2), superoxide anion (O2•-), hydroxyl radical (•OH), nitric oxide (NO•), peroxynitrite (ONOO-), hypochlorous acid (HOCl), hydrogen peroxide (H2O2) alkoxyl radical (LO•), and the peroxyl radical (L-•2).

There are also carbon-centered, hydrogen-centered, and suphur-centered free radicals.
Free radicals are produced in our bodies by a process referred to as auto-oxidation, which is part of our normal breathing that results in the reduction of the oxygen diradical and the formation of reactive oxygen species, primarily Superoxide.

Free radicals are also formed in our body in others ways including via a variety of enzyme systems capable of generating large amounts of free radicals, including xanthine oxidase, and via other metabolic activities in our body. We also get free radicals from a number of sources outside our body including via drugs. Such drugs include antibiotics that depend on quinoid groups or bound metals for their action such as nitrofurantoin, and anti-cancer drugs such as bleomycin and methotrexate.

Radiation treatment, smoking tobacco, inhalation of inorganic particles such as asbestos and silica, and ozone inhalation, even fever, are sources of free radicals. Oxidative stress is the state in which the level of toxic reactive oxygen intermediates (ROI) overcomes our internal antioxidant defences. This results in an excess of free radicals, which can react with cellular lipids, proteins, and nucleic acids, leading to local injury and can ultimately damage our organs and cause disease.

Antioxidants such as vitamin E combat oxidation and prevent oxidative stress. These substances protect other chemicals in our body from damaging oxidation reactions by reacting with free radicals and other reactive oxygen species in us. While Vitamin E and other antioxidants are trying to prevent e process of oxidation, they sacrifice themselves by becoming oxidized.

Anti-oxidant supply is limited, particularly if you are not taking regular vitamin E supplements, and one antioxidant molecule can only react with a single free radical. There is therefore, a constant need to replenish your antioxidant stores, through supplementation.

Also, you know that exercise is a great way to prevent or delay age-related diseases such as heart disease, cancer, and Alzheimer's. And perhaps you've heard that vitamin E supplements have potent antioxidant properties that also help. So how about both combined?

They provide a better defense than either strategy alone against several ailments caused or worsened by age, according to a study in the July 2003 issue of Biological Research for Nursing.

Antioxidants such as vitamin C, vitamin E, CoQ10, glutathione, and alpha lipoic acid are important supplements for everyone, but especially for those who exercise on a regular basis. The rational is that exercise is a highly oxidative process and, as a consequence, produces free radicals from aerobic metabolism. Antioxidant compounds help alleviate this process.

References
Ames BN, Shigenaga MK, Hagen TM. Oxidants, antioxidants, and the degenerative diseases of aging. Proc Natl Acad Sci 1993;90:7915-22.
Biological Research for Nursing, July 2003. Nutrition, October 2001.
American Journal of Epidemiology, Feb. 15, 1999.