"The Role of Vitamin E as an Antioxidant"
Jimmy Lopez
Many of us know that free radicals are bad for our health and antioxidants are good. Any further explanation may be difficult for most people. A scientific explanation of a free radical would be any molecule or atom that has an unpaired electron in its outer shell (Sharma, 1995). This unpaired electron is highly energetic and causes the molecule or atom to become unstable. The result is that it tries to balance itself by grabbing an electron from another molecule or atom. These unshared electrons can react with oxygen or nitrogen contained in other molecules. The resultant is a free radical that is either a reactive oxygen species (ROS) or a reactive nitrogen species (RNS) (Gropper, Smith, Groff, 2009). Free radicals can be produced through natural physiological processes such as digestion and our body’s natural immunological response to foreign bodies. They can also be produced through exposure to environmental pollutants. They are produced in our body everyday in high numbers. Free radicals are damaging to the cells in our body. Damage occurs when free radicals exist at greater levels than antioxidants. When the cumulative cell injury is great enough that it becomes obvious the result is disease (Esselstyn, 2008). To combat free radicals, the body utilizes antioxidant enzymes and nutrients. Antioxidants have the ability to neutralize and stop reactions involving free radicals (Gropper, Smith, Groff, 2009). The body needs to transform free radicals into something else and antioxidants aide in this function. Some examples of antioxidant nutrients are vitamin c, beta-carotene and the focus of this article, vitamin e.
Vitamin E
Vitamin E is a fat-soluble antioxidant. The most important function of Vitamin E is protecting and maintaining membrane stability within the cells of our body (Gropper, Smith, Groff, 2009). It does this by stopping the production of free radicals that occur with the oxidation of unsaturated fats found within the membranes of our cells (National Institute of Health). Besides helping to maintain cell stability it is also thought that Vitamin E helps in the prevention of heart disease. Scientific studies have shown that Vitamin E slows the formation of atherosclerotic plague within the blood vessels of our body (Blumberg, 2002). Low-density lipoprotein (LDL) cholesterol is believed to play a major role in cardiovascular disease. Studies have shown that Vitamin E inhibits the oxidation of LDL (National Institute of Health).
Sources
There are many sources of food, both plant and animal, that contains Vitamin E. In plants, Vitamin E can be found in vegetable oils, sunflower seeds, wheat germ, nuts and whole grains (Stanfield, Hui, 2009). In animal products Vitamin E is found in the fatty tissue where it has been stored by the animal that consumed it. Liver, codfish, and butter are considered good sources of Vitamin E. It is important to note that plant based sources are superior to animal based sources in providing Vitamin E (Gropper, Smith, Groff, 2009). Consuming Vitamin E from animal based products means that you are consuming what that animal had stored in its fat from sources of Vitamin E it consumed. It would seem more practical to consume your Vitamin E directly from plant-based sources. It is also important that you try to obtain Vitamin E through natural sources. Research has shown that natural sources of Vitamin E are absorbed at much higher rates than synthetic versions (Challen, 2001). This would mean that you would have to consume much higher levels of a synthetic version to equal a smaller natural dose. Not only does it take the body longer to absorb synthetic Vitamin E, the body will also excrete it faster than a natural form (Challen, 2001). So a synthetic form takes longer to absorb and is excreted faster.
Vitamin E Recommended Intakes
Dietary deficiency for Vitamin E is uncommon. Vitamin E is absorbed in the digestive tract aided by fat. People who have fat-malabsorption disorders may be most likely to be deficient in Vitamin E. High doses of supplemental Vitamin E has been shown to increase the risk of hemorrhage and blood clotting (National Institute of Health). Listed below are the recommended intakes for Vitamin E for adults.
Recommended Dietary Allowances (RDAs)
15mg, (22.4 IU)
Tolerable Upper Intake Levels (ULs)
1,000 mg, (1,500 IU)
References
Sharma, H. (1995). Free radicals: a major cause of aging. Consumer Health, 18(2), Retrieved from http://consumerhealth.org/articles/display.cfm?ID=19990303172533
Gropper, A., Smith, J. L., & Groff, J. L. (2009). Advanced nutrition and human metabolism. Belmont, Ca.: Wadsworth Pub Co. Retrieved from http://books.google.com/books/feeds/volumes?q=978-0-495-11657-8
Esselstyn, C. (2008). Prevent and reverse heart disease. NY, NY: Penguin Group.
Stanfield, P. T., & Hui, Y. H. (2010). Nutrition and diet therapy. (5th ed.). Sudbury, MA: Jones and Bartlett
Blumberg, J. (2002). Unraveling the conflicting studies on vitamin e and heart disease. Retrieved from http;//lpi.oregonstate.edu/ss02/blumberg.html
Challem, J. (2001, November). Natural vs. synthetic vitamin e. Nutrition Science News, Retrieved from http://www.chiro.org/nutrition/full/natural_vs_synthetic_vitamin_e_shtml
