Antioxidant Function and Health Implications of Vitamin E



Ching Kuang Chow*, 1, Hannah S Chow-Johnson2
1 Department of Dietetics and Human Nutrition, and Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY 40506-0054, USA
2 Department of Pediatrics, Loyola University Medical Center, North Riverside, IL 60154, USA


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© 2013 Chow and Chow-Johnson

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Dietetics and Human Nutrition, and Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY 40506-0054, USA; Tel: 1-859-257-7783; Fax: 1-859-257-3707; E-mail:ckchow@uky.edu


Abstract

Superoxide, a key precursor of important reactive oxygen/nitrogen species (ROS/RNS), may release iron from its protein complex. By mediating the generation and/level of superoxide, vitamin E, the most important fat-soluble anti-oxidant and free radical scavenger, may exert its antioxidant function by limiting the formation of reactive hydroxyl radi-cals and peroxynitrite. The antioxidant function of vitamin E is augmented by GSH peroxidase and related metabolic sys-tems which respond adaptively and compensatively to oxidative stress. By mediating the levels of ROS/RNS, vitamin E may also modulate the activation and/or expression of redox-sensitive biological response modifiers, and thereby attenu-ate the cellular events leading to the onset and development of aging and other degenerative disorders. Earlier epidemiol-ogical data and retrospective studies show an association between increased intake of vitamin E and reduced risk of car-diovascular disease, cancer, and other disorders. However, subsequent prospective randomized placebo-controlled studies and interventional trials have provided inconsistent findings. Data available from recent large-scale interventional trials suggest that vitamin E supplements at high doses are not beneficial.

Keywords: Vitamin E, tocopherols, superoxide, biological function, health benefit.