Vitamin B7, Vitamin B9, Vitamin B12

6. Vitamin B7 (Biotin)

It is required for the metabolism of fatty acids, amino acids, and formation of urine, As in the case of vitamin B3, many foods contain this vitamin so deficiencies are infrequent.
Avidin is a protein found in albumin (egg-white) which combines with biotin within the intestine, thus preventing the absorption of this vitamin. The structure of avidin is altered through boiling and loses its ability to bind with biotin, so allowing it to be absorbed.

7. Vitamin B9 (Folic acid)
It is required for amino acid metabolism and formation of red blood cells. The symptoms of its deficiency are anaema and painful skin. Folic acid functions as a coenzyme and participates in synthesis reactions, especially in nucleic acid synthesis. A rich source of vitamin B9 is spinach.


8. Vitamin B12 (Cyanocobalamin)

It is required for DNA synthesis and consequently for cell division and red blood cell formation. Vitamin B12 stimulates the red bone marrow in the production of RBC. A lack of vitamin B12 results in anaemia and causes lack of absorption in the small intestine. Its absorption is controlled by intristic factor in the stomach. In a deficiency of intristic factor, B12 can not pass through into the blood.
It is  abundant in anima products such as liver, milk, meat, kidney, eggs and yeast. However, vitamin B12 is not present in plant material. This vitamin may also be synthesised by the bacterial flora of the large intestine.