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A History of Vitamin E

2012; Karger Publishers; Volume: 61; Issue: 3 Linguagem: Inglês

10.1159/000343106

1421-9697

Etsuo Niki, Maret G. Traber,

Retinoids in leukemia and cellular processes

Vitamin E (α-tocopherol) was discovered nearly 100 years ago because it was required to prevent fetal resorption in pregnant, vitamin E-deficient rats fed lard-containing diets that were easily oxidizable. The human diet contains eight different vitamin E-related molecules synthesized by plants; despite the fact that all of these molecules are peroxyl radical scavengers, the human body prefers α-tocopherol. The biological activity of vitamin E is highly dependent upon regulatory mechanisms that serve to retain α-tocopherol and excrete the non-α-tocopherol forms. This preference is dependent upon the combination of the function of α-tocopherol transfer protein (α-TTP) to enrich the plasma with α-tocopherol and the metabolism of non-α-tocopherols. α-TTP is critical for human health because mutations in this protein lead to severe vitamin E deficiency characterized by neurologic abnormalities, especially ataxia and eventually death if vitamin E is not provided in large quantities to overcome the lack of α-TTP. α-Tocopherol serves as a peroxyl radical scavenger that protects polyunsaturated fatty acids in membranes and lipoproteins. Although specific pathways and specific molecular targets have been sought in a variety of studies, the most likely explanation as to why humans require vitamin E is that it is a fat-soluble antioxidant.