Vitamin E: the shrew waiting to be tamed.
Vitamin E is the last of all vitamins whose essentiality is not yet understood. Its widely accepted role as a lipophilic antioxidant has been questioned, since proof of its in vivo relevance remained scarce. The influence of vitamin E on biomarkers of oxidative stress in vivo is inconsistent and metabolites of vitamin E having reacted as an antioxidant are hardly detectable. Novel functions of vitamin E include the regulation of enzymes, most of which are membrane bound or activated by membrane recruitment. Also, expression of genes responds to vitamin E. The search for a transcription factor common to all regulated genes failed so far and a receptor that specifically binds vitamin E has not yet been identified. According to microarray data, pathways preferentially affected by the vitamin E status are the inflammatory response and cellular traffic. A role of vitamin E in cellular trafficking could best explain the neurological symptoms seen in vitamin E deficiency. Emerging knowledge on vitamin E is compiled here with the perspective to unravel the molecular mechanisms that could more likely explain the essentiality of the vitamin than its ability to scavenge free radicals.
Brigelius-Flohé
Regina
R
German Institute of Human Nutrition Potsdam-Rehbruecke, Department of Biochemistry of Micronutrients, Nuthetal, Germany. flohe@dife.de
D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D004789:Enzyme Activation / Q000502:physiology*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D019636:Neurodegenerative Diseases / Q000235:genetics / Q000378:metabolism*; D021041:Placental Circulation / Q000502:physiology; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011940:Receptor Aggregation / Q000502:physiology*; D014810:Vitamin E / Q000502:physiology*; D014811:Vitamin E Deficiency / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*
D051017:Apoptosis Regulatory Proteins; D014810:Vitamin E