Vitamin-B7 a water soluble vitamin found both naturally and in synthesized form also known as anti-egg vitamin. Structurally consist of two rings a uriedo ring with a thiopene ring with an additional valeric acid side chain.

DATS of Vitamin B7

DATS (DIGESTION, ABSORPTION, TRANSPORTATION AND STORAGE) OF VITAMIN-B7 biotin

Sources:

Sources of biotin for humans include either dietary sources and the other is the biotin formed by the intestinal bacterial flora. This bacterial flora produced too much of biotin that is enough for human requirement. In addition to this some important dietary sources are soy bean, egg yolk, meat, liver, kidney, cereal, legumes and nuts.

In foods it is present either attached with proteins or either in attachment with lysine known as biocytin and sometimes biotinyl lysine.

Why the Biotin Does not Absorb If The Egg Are Taken Uncooked?

Avidin is a glycoprotein which binds the biotin irreversibly to it which prevents its absorption when the Egg are taken in an uncooked form. However, avidin is a heat labile compound due to heat treatment it breaks and the biotin are free for absorption.

 

RDA (recommended dietary allowances):

The recommended dietary allowances are different for the individuals of different age groups. RDA for males, females and children are:

Gender

RDA

Men

30 micro gram

Women

30 micro gram

Children

8-12 micro gram

 

Functions of vitamin B7 in Human body:

Vitamin B7 performs many important roles in human body these are:

  • It acts as a co enzyme and helps to produce energy by working with enzyme that breakdown Fats, Carbohydrates and proteins to yield energy.
  • It also helps in synthesis and function of DNA.
  • It is also helpful to promote hair growth and provides good nourishment to hairs, nails and skin.

DATS (digestion, absorption, transportation and storage) of vitamin B7:

Digestion:

Protein bound biotin requires digestion by proteolytic enzymes prior to its absorption. Proteolysis by proteases causes the conversion of protein attached biotin to biotin, biocytin and biotinyl peptidase. These biotin, biocytin and biotinyl peptidases are further digest and converts into its smallest forms. These biotinidase and proteinyl peptidases are present in pancreatic juices, bile and other enzymes secreted in the intestine.

Absorption:

Free biotin absorb primarily in the jejunum followed by ileum. Biotin absorption occurs by passive diffusion if are taken by pharmaceutical doses. Biotin that is synthesized by colonial bacteria is absorbed in the proximal and mid transverse colon.

Transportation:

The main carrier for Biotin are found in small intestine as well as in liver called sodium dependent multi vitamin transporter (SMVT). Another carrier that is present in the tissues is SLC19A3. MCT (mono carboxylate transporter) are present in the blood for its transportation. About 80% of the biotin are found in an unbound form in plasma. These transporters bind biotin to it and transport it towards liver and other body tissues where it required.

Storage:

Biotin is a water soluble vitamin and it does not store in human body. Only small amount of biotin are stored in liver, muscles and brain.

Deficiency:

Biotin deficiency is characterized by lethargy, depression, hallucination, muscle pain, paresthesia, hair loss, brittle hair, red dermatitis, scaly etc.

Biotin deficiency occur in people who ingest raw eggs because avidin are bind to biotin due to which its absorption is diminished. People having genetic defects involving biotinidase and holocarboxylase synthetase will lead to deficiencies.

Mechanism Of Action:

For co enzyme action with in a cell, biotin is attached to four carboxylases:

Pyruvate Carboxylases

Pyruvate carboxylase is an important enzyme that helps in the carboxylation of pyruvate to oxaloacetate. It depends on the concentration of acetyl CoA, ATP and Mg+2.

Acetyl Co A

It act as an initiation for fatty acid synthesis. Its activity is activated by citrate and isocitrate.