Vitamin E is a soluble vitamin covering a set of eight organic molecules: four tocopherols and four tocotrienols. The biologically most active form is the α-tocopherol, the most abundant in the diet is the γ-tocopherol. These molecules are present in large quantities in vegetable oils. They act in conjunction with the vitamin C and glutathione essentially as antioxidants against the reactive oxygen species produced in particular by the oxidation of fatty acids.
In 1922, the embryologist Herbert McLean Evans and his assistant Katharine Scott Bishop from the University of California at Berkeley, noted that in rats subjected to a diet with depleted lipids, females can got pregnant but no fetus developed. However, pregnancies successfully came to an end when the diet was supplemented with lettuce leaves or wheat germ. The two scientists suspected the existence of a lipophilic compound, which they called X Factor essential for fetal development.
Free sample research paper on vitamin E will tell you that in 1924, independent research of Herbert Evans and Katherine Bishop, Bennett Sure from the University of Arkansas showed a compound removed from a diet-induced infertility in male rats. Sure Bennett called this compound Vitamin E, the letters A, B, and C had already been used, and the letter D being approached for antirachitic factor. Vitamin E also received the name of tocopherol from the Greek tokos : offspring and pherein : wear.
Herbert Evans and Oliver Emerson was able to isolate the vitamin E from wheat germ oil in 1936, and Erhard Fernholz determined its structure in 1938. The same year, the Nobel Prize in Chemistry Paul Karrer showed the synthesis of racemic alpha-tocopherol. It was not until 1968 that vitamin E was recognized as an essential nutrient for humans by the National Research Council of the United States.
Tocopherols are composed of a chromanol nucleus and a saturated side chain wth 16 atoms of carbon. Tocopherols differ from tocotrienols in the presence of three double bonds on the side chain.
The difference between the forms alpha, beta, gamma, and delta is the number and position of methyl groups on the chromanol ring.
In addition to its antioxidant role, vitamin E prevents excessive aggregation of platelets responsible for thrombosis, has a protective effect on red blood cells and may prevent, in this way, the origin of the cardio-vascular disease. In practice, however, no action in this direction has been demonstrated. In addition, it would increase the rate of the strokes of hemorrhagic type.
A favorable effect on the prevention of certain cancers was suspected at first, but has not been confirmed by the most recent studies. Supplementation with vitamin E may even increase the risk of prostate cancer.
Vitamin E has also a beneficial effect on cholesterol. Although Evans observations have shown the importance of vitamin E on fertility of certain animals, no effect has been demonstrated in humans.
It may also protect against the PD in preventing the oxidation of fatty acids omega-3 and iron.
It is used in addition to antidepressant when the latter is sufficiently operative.
It would also have some effect on nonalcoholic steatosis to slow their progression to cirrhosis.
In excessive doses (more than 400 contributions IU / day), vitamin E as alpha-tocopherol form alone could increase the overall mortality.
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