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

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.