Explain the details of vitamin B12 absorption.
Explain the details of vitamin B12 absorption.
Vitamin B12 is a water soluble vitamin which is present naturally in some foods. The compounds containing this vitamin are also called as cobalamins due to the presence of the mineral cobalt. The metabolically active forms of the is vitamin are methylcobalamine and 5-deoxyadenosylcobalamin.
This vitamin can also be taken as supplements available in the multivitamin/multimineral supplements, in B-complex supplements and in supplements which contain only vitamin B12.
For the development, myelination, functions related to the central nervous system, formation of healthy red blood cells and synthesis of DNA there is requirement of this vitamin.
This vitamin normally binds to the proteins present in the ingested food. For its absorption in the body, it has to be released from this protein.The process of releasing starts in the oral cavity when the mixing of food takes place with saliva. A cobalamin binding protein called as haptocorrin present in saliva binds with this freed protein.
The further release of vitamin B12 from food takes place in the stomach. Here, due to the activity of hydrochloric acid and gastric protease, the release takes place. Then the binding of this released vitamin with haptocorrin takes place here.
In the duodenum, this vitamin is released from haptocorrin with the help of digestive enzymes. Now this freed vitamin is able to bind with the intrinsic factor released by the parietal cells of the stomach. Now, by the receptor mediated endocytosis, the absorption of this formed complex takes place in the distal ileum.
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