Vitamin E - Occurrence, Absorption and Storage
Occurrence of Vitamin E
It occurs in both animal and plant kingdoms. Animal sources are meat, Liver, eggs, fish, liver oil, milk (human milk is 2 to 4 times richer than cow’s milk) and butter. Plant sources are the best and include wheat germ oil (from which it was first isolated) and to a lesser extent cotton-seed oil, corn oil and peanut oil. All green leaf vegetables also contains this vitamin. Many other compounds including those having entirely different structures show vitamin E activity. Water solubilized vitamin products are also available now. A synthetic product is being used at present in clinical practice.
Absorption and storage of Vitamin E
It is not very efficient and only 40% of the amount ingested is absorbed. Bile salts and fats increase its absorption. It is absorbed from the gastrointestinal tract by a mechanism probably similar to that for other fat soluble vitamins. It first appears in the chylomicrons and then primarily associated with β-lipoproteins. In body it mainly occurs in muscles and adipose tissue but on weight basis pituitary and adrenal glands have the highest concentration of vitamin E
Further Description of Vitamin E
There are many compounds with Vitamin E activity all of which are tocopherols. These are alpha, beta, gamma, delta eta, zeta and epsilon tocopherols. All of these are derivatives of tocol whose chemical structure is shown below
![](bio/vitamin E.gif)
The most active vitamin E is 5:7:8-trimethyltocl and is called α-tocopherol. Other tocopherols differ from each other in having a different distribution of methyl groups. The origin of the name tocopherol is from “tocos” meaning child birth and “phero” meaning to bear implying a substance which increases fertility; “ol” represents an alcohol. Vitamin E is a light yellow oil, stable to heat and acids. Its “d” form is more active than “l” form.