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Vitamin E
 
 
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Vitamin E is the collective name for a set of 8 related a-, ß-, ?-, and d-tocopherol
Tocopherol

Tocopherol, a class of chemical compounds of which many have vitamin E activity, describes a series of organic compounds consisting of various methylated phenols....
s and the corresponding four tocotrienols, which are fat-soluble vitamin
Vitamin

A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. A compound is called a vitamin when it cannot be biosynthesis in sufficient quantities by an organism, and must be obtained from the diet....
s with antioxidant
Antioxidant

An antioxidant is a molecule capable of slowing or preventing the Redox of other molecules. Oxidation is a chemical reaction that transfers electrons from a substance to an oxidizing agent....
 properties. Of these, a-tocopherol (also written as alpha-tocopherol
Alpha-tocopherol

α-Tocopherol is a type of tocopherol with formula C29H50O2. It has E number "E307"....
) has been most studied as it has the highest bioavailability
Bioavailability

In pharmacology, bioavailability is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetics properties of medication....
.

It has been claimed that a-tocopherol is the most important lipid-soluble antioxidant, and that it protects cell membrane
Cell membrane

The cell membrane is the interface between the cellular machinery inside the cell and the fluid outside.It is a semipermeable lipid bilayer found in all cell ....
s from oxidation by reacting with lipid radicals produced in the lipid peroxidation
Lipid peroxidation

Lipid peroxidation refers to the redox degradation of lipids. It is the process whereby Radical "steal" electrons from the lipids in cell membranes, resulting in cell damage....
 chain reaction
Chain reaction

A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, positive feedback leads to a self-amplifying chain of events....
.






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Vitamin E is the collective name for a set of 8 related a-, ß-, ?-, and d-tocopherol
Tocopherol

Tocopherol, a class of chemical compounds of which many have vitamin E activity, describes a series of organic compounds consisting of various methylated phenols....
s and the corresponding four tocotrienols, which are fat-soluble vitamin
Vitamin

A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. A compound is called a vitamin when it cannot be biosynthesis in sufficient quantities by an organism, and must be obtained from the diet....
s with antioxidant
Antioxidant

An antioxidant is a molecule capable of slowing or preventing the Redox of other molecules. Oxidation is a chemical reaction that transfers electrons from a substance to an oxidizing agent....
 properties. Of these, a-tocopherol (also written as alpha-tocopherol
Alpha-tocopherol

α-Tocopherol is a type of tocopherol with formula C29H50O2. It has E number "E307"....
) has been most studied as it has the highest bioavailability
Bioavailability

In pharmacology, bioavailability is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetics properties of medication....
.

It has been claimed that a-tocopherol is the most important lipid-soluble antioxidant, and that it protects cell membrane
Cell membrane

The cell membrane is the interface between the cellular machinery inside the cell and the fluid outside.It is a semipermeable lipid bilayer found in all cell ....
s from oxidation by reacting with lipid radicals produced in the lipid peroxidation
Lipid peroxidation

Lipid peroxidation refers to the redox degradation of lipids. It is the process whereby Radical "steal" electrons from the lipids in cell membranes, resulting in cell damage....
 chain reaction
Chain reaction

A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, positive feedback leads to a self-amplifying chain of events....
. This would remove the free radical intermediates and prevent the oxidation reaction from continuing. The oxidised a-tocopheroxyl radicals produced in this process may be recycled back to the active reduced form through reduction by other antioxidants, such as ascorbate, retinol
Retinol

Retinol, the animal form of vitamin A, is a fat-soluble vitamin important in visual system and bone growth. It is also a Terpenoid. Retinol is among the most useable forms of vitamin A, which also include Retinal , Retinoic acid and retinyl ester ....
 or ubiquinol
Ubiquinol

Ubiquinol is a benzoquinol and is the reduced product of ubiquinone also called coenzyme Q10....
. However, the importance of the antioxidant properties of this molecule at the concentrations present in the body is not clear and it is possible that the reason why vitamin E is required in the diet is unrelated to its ability to act as an antioxidant.. Other forms of vitamin E have their own unique properties. For example, ?-tocopherol (also written as gamma-tocopherol) is a nucleophile
Nucleophile

In chemistry, a nucleophile is a reagent that forms a chemical bond to its reaction partner by donating both bonding electrons. Because nucleophiles donate electrons, they are by definition Lewis bases ....
 that may react with electrophilic
Electrophile

In chemistry, an electrophile is a reagent attracted to electrons that participates in a chemical reaction by accepting an electron pair in order to Chemical bond to a nucleophile....
 mutagens; and the tocotrienol
Tocotrienol

Tocotrienols ? together with tocopherols ? compose the vitamin E family. Natural tocotrienols exist in four different forms or isomers, named alpha-, beta-, gamma- and delta- tocotrienol, each which contain different number of methyl groups on the chromanol ring....
s having specialized roles in protecting neuron
Neuron

Neurons are responsive cell in the nervous system that process and transmit information by electrochemical Signal . They are the core components of the brain, the vertebrate spinal cord, the invertebrate ventral nerve cord, and the peripheral nerves....
s from damage, cancer prevention and cholesterol reductionby inhibiting the activity of HMG-CoA reductase[16-1];d-tocotrienol blocks processing of sterol regulatory element-binding proteins (SREBPs)[16-1].However, the roles and importance of all of the various forms of vitamin E are presently unclear, and it has even been suggested that the most important function of vitamin E is as a signaling molecule
Cell signaling

Cell signaling is part of a complex system of communication that governs basic cellular activities and coordinates cell actions. The ability of cells to perceive and correctly respond to their microenvironment is the basis of development, tissue repair, and immunity as well as normal tissue homeostasis....
, and that it has no significant role in antioxidant metabolism.

Most studies about vitamin E have supplemented using only the synthetic alpha-tocopherol, but doing so leads to reduced serum gamma- and delta-tocopherol concentrations. Moreover, a 2007 clinical study involving synthetic alpha-tocopherol concluded that supplementation did not reduce the risk of major cardiovascular events in middle aged and older men. For more info, read article tocopherol
Tocopherol

Tocopherol, a class of chemical compounds of which many have vitamin E activity, describes a series of organic compounds consisting of various methylated phenols....
.

Food sources of Vitamin E


Particularly high levels of vitamin E can be found in the following foods:
  • Avocado
    Avocado

    The avocado , also known as palta or aguacate , butter pear or alligator pear, is a tree native to Mexico, South America and Central America, classified in the flowering plant family Lauraceae....
  • Nuts
    Nut (fruit)

    Nut is a general term for the large, dry, oily seed or fruit of some plant. While a wide variety of dried seeds and fruits are called nuts, only a certain number of them are considered by biologists to be true nuts....
    , such as almonds or hazelnuts
  • Red Palm Oil
  • Seeds
    SEEDS

    SEEDS is a voluntary organisation registered under the Societies Act of India.SEEDS was formed in 1994 as an informal group of students and pedagogues of the School of Planning and Architecture, New Delhi, whose common interests brought them together and made them carry human habitat environment related exercises beyond set academic target...
  • Spinach
    Spinach

    Spinach is a flowering plant in the family of Amaranthaceae. It is native to central and southwestern Asia. It is an annual plant , which grows to a height of up to 30 cm....
     and other green leafy vegetables
  • Vegetable oils -- Canola
    Canola

    Canola is one of two cultivars of rapeseed or Field mustard . Their seeds are used to produce edible oil that is fit for human consumption because it has lower levels of erucic acid than traditional rapeseed oils and to produce livestock feed because it has reduced levels of the toxin glucosin....
    , corn
    Maize

    Maize , known as corn in some countries, is a cereal domesticated in Mesoamerica and subsequently spread throughout the American continents....
    , sunflower
    Sunflower

    The sunflower is an annual plant in the family Asteraceae and native to the Americas, with a large flowering head . The stem can grow as high as 3 meters , and the flower head can reach 30 cm in diameter with the "large" seeds....
    , soybean
    Soybean

    The soybean or soya bean is a species of legume native to East Asia. The plant is classed as an oilseed rather than a Pulse . It is an annual plant that has been used in China for 5,000 years as a food and a component of drugs....
    , cottonseed, olive oil
    Olive oil

    Olive oil is a fruit oil obtained from the olive , a traditional tree crop of the Mediterranean Basin. The wild olive tree originated in Anatolia and spread from there as far as southern Africa, Australia, Japan and China....
  • Wheat germ
  • Wholegrain foods
  • Milk
  • Asparagus
    Asparagus

    Asparagus officinalis is a flowering plant species in the genus Asparagus from which the vegetable known as asparagus is obtained....


Vitamin E and prostate cancer study discontinued


There have been some theories that Vitamin E, especially when coupled with selenium
Selenium

Selenium is a chemical element with the atomic number 34, represented by the chemical symbol Se, an atomic mass of 78.96. It is a nonmetal, chemically related to sulfur and tellurium, and rarely occurs in its elemental state in nature....
, may reduce the risk of prostate cancer by 30 percent. However, the Selenium and Vitamin E Cancer Prevention Trial, ("SELECT"), run from 2004 to 2008, found that vitamin E, whether taken alone or in combination with selenium, did not prevent prostate cancer. The SELECT study was discontinued after independent reviewers determined that there was no benefit to the 35,000 men who were the subject of the study.

Further reading


External links

  • Medline Plus, Medical Encyclopedia, U.S. National Library of Medicine
  • Office of Dietary Supplements, National Institutes of Health