Vitamin B12 in human body

Vitamin B12, also called cobalamin is a water-soluble vitamin obtained through the ingestion of fish, meat, and dairy products, as well as fortified cereals and supplements.

It is an indispensable molecule with a very complex structure and an intricate pathway of absorption and cellular trafficking that requires molecular escort proteins in body fluids and intracellular chaperones.

Vitamin B12 is an essential water-soluble vitamin that is commonly found in a variety of foods such as fish, shellfish, meat, and dairy products. Vitamin B12 is frequently used in combination with other B vitamins in a vitamin B complex formulation.

The vitamin is a cobalt-containing coordination compound generated by intestinal microbes, and a natural water-soluble vitamin of the B-complex family that must combine with Intrinsic Factor (IF) for absorption by the intestine. Vitamin B12 enters the circulation about 3–4 hours later bound to TC (transcobalamin).

Vitamin B12 is a nutrient that helps keep the body’s nerve and blood cells healthy and helps make DNA, the genetic material in all cells. Vitamin B12 also helps prevent a type of anemia called megaloblastic anemia that makes people tired and weak.

Cobalamin is necessary for hematopoiesis, neural metabolism, DNA and RNA production, and carbohydrate, fat, and protein metabolism. B12 improves iron functions in the metabolic cycle and assists folic acid in choline synthesis.
Vitamin B12 in human body

Milk contain vitamin B12

Vitamin B12 Deficiency

Vitamin B12 or cobalamin is a very complex chemical compound. Cobalamin is referring to the group of cobalt containing vitamer compound, this include cyanocobalamin, hydroxocobalamin, 5-deoxyadenosylcobalamin and methylcobalamin.

This vitamin required for the normal development of red blood cells, and a deficiency it causes acute pernicious anemia and a variety of other disorders. The exact requirement of Vitamin B-12 is yet unknown, since some B12 is synthesized by bacteria in the intestine. The organs of animals are excellent sources of Vitamin B12 and the muscles of warm-blooded animals and fish are good sources.

Vitamin B12 deficiency is commonly asymptomatic, but can also present as anemia characterized by enlarged blood corpuscle, so called megaloblastic anemia. However in serious case deficiency can potentially cause severe and irreversible damage to the nervous system.

Since body stores of vitamin B12 are adequate for up to five years, deficiency is generally the result of failure to absorb it. In older people, is also caused by inadequate intake of impaired absorption.

Megaloblastic anemia, Crohn's disease and other intestinal disorders are the most frequent causes of vitamin B12 deficiency.

Symptoms are attributable primarily to anemia, although glossitis, jaundice, and splenomegaly may be present. Vitamin B12 deficiency may cause decreased vibratory and positional sense, ataxia, paresthesias, confusion.

Apart from anemia due to vitamin B12 deficiency, the neurologic symptom of vitamin B12 deficiency include numbness and tingling of the arms and more commonly the legs, difficulty walking, memory loss, disorientation and dementia with or without mood changes.

Neurological or psychiatric symptoms occurs in about 40% of patents with vitamin B12 deficiency, in association with progressive damage to the spinal cord, peripheral nerves and cerebrum.
Vitamin B12 Deficiency