1932

Abstract

Abstract

Dietary and supplemental vitamin E is absorbed and delivered to the liver, but of the various antioxidants with vitamin E activity, only α-tocopherol is preferentially recognized by the α-tocopherol transfer protein (α-TTP) and is transferred to plasma, while the other vitamin E forms (e.g., γ-tocopherol or tocotrienols) are removed from the circulation. Hepatic α-TTP is required to maintain plasma and tissue α-tocopherol concentrations. The liver is the master regulator of the body's vitamin E levels in that it not only controls α-tocopherol concentrations, but also appears to be the major site of vitamin E metabolism and excretion. Vitamin Es are metabolized similarly to xenobiotics; they are initially ω-oxidized by cytochrome P450s, undergo several rounds of β-oxidation, and then are conjugated and excreted. As a result of these various mechanisms, liver α-tocopherol and other vitamin E concentrations are closely regulated; thus, any potential adverse vitamin E effects are limited.

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/content/journals/10.1146/annurev.nutr.27.061406.093819
2007-08-21
2024-06-23
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  • Article Type: Review Article
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