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Physiological Effects of Vitamin E
By: Peter T. Pugliese, MD
Posted: August 17, 2009, from the September 2009 issue of Skin Inc. magazine.
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An additional major role of vitamin E is to control the coagulation of blood, which occurs stepwise. Vitamin E’s antithromboticc and anticoagulant activities are quite complex because they involve the regulation of cellular activities. One function to control clotting is the down regulationd of the factor responsible for intracellular cell adhesion, and the molecule that causes vascular cell adhesion. When these molecules are lower, the adhesion of blood components to the endothelium, or lining of the blood vessels, is reduced. A second function in preventing clotting is the up regulation of cytosolic phospholipase A2 and cyclooxygenase, which are two substances that release of prostacyclin, a vasodilating factor and inhibitor of platelet aggregation. Platelets are needed in blood coagulation (aspirin also reduces platelet aggregation), and, along with this function, vitamin E decreases plasma production of thrombin, a protein that binds to platelets and induces aggregation.
Immunomodulatory and antiviral effects
The neuroprotective effects of vitamin E are most likely due to its antioxidant effects. Nervous tissue, being a lipid-covered structure and subjected to lipid peroxidation, can easily be a victim of oxidative stress. Vitamin E, being lipid-soluble, can protect against oxidative stress in the nervous system. Vitamin E has been observed to be an antioxidant in tissue-cultured cells. Using the T lymphocyte as a model cell and the increase in mitosis as a response, alpha tocopherol produced an increase in the number of T lymphocytes in aged mice. The T lymphocyte is an important component of the immune system. The mechanism of this mitotic activity makes it apparent that it is produced by vitamin E. It is possible that the antiviral effects of vitamin E against HIV-1 are related to an antioxidant activity since Vitamin E is known to counteract the biological stress from oxidation, and oxidation is known to contribute to the pathogenesis of HIV-1 viral infections. One theory is that since vitamin E helps to control the integrity and fluidity of the cell membrane, it is possible that by altering membrane fluidity of HIV-1, virus 1 is not able to bind to cell-receptor sites. Cell infection in most viruses requires that they bind to some part of the cell, and then enter the cell to place their DNA, or RNA, in the cell nucleus. If they cannot do this, the infectivity of the virus is markedly reduced.
Vitamin E and NF kappa B
Much of the body’s inflammation is mediated by a cellular compound known as nuclear factor kappa B. These proteins are a family of eukaryotic transcription factors that are involved in the control of a large number of normal cellular processes, such as immune and inflammatory responses, developmental processes, cellular growth and apoptosis. These transcription factors are very active in a number of disease states, such as cancer, arthritis, chronic inflammation, asthma, neurodegenerative diseases and heart disease.
You should be aware of this process because it involves the tocotrienols and a major pathway to tumorogenesis. Very little is known about tocotrienols, but a recent research article investigated the role a-tocotrienol had on the NF-kB pathway. Their results showed that ?-tocotrienol completely abolished NF-kB activation, while a similar dose of a tocopherol was noted to have no effect. Their results show that ?-tocotrienol suppressed the NF-kB activated by a variety of stimuli, suggesting that it acts at a step common to all these activators, but equally important, they found that atocotrienol blocked the activation of NF-kB without directly interfering with the DNA binding of NF-kB. This is very important since NF-kB is critical to many normal body defense functions.
In summary, vitamin E functions depend on its antioxidant ability, which means vitamin E stops free radicals propagations. It helps to protect the nervous system, the musculoskeletal system and the retinas. It is believed to reduce lipid peroxidation in cells and proteins, to protect DNA, and to help prevent cancer and arteriosclerosis.