Human Anatomy and Physiology : III. Vitamins And Nutrition Part-II

Vitamin A is largely stored in the liver in the human body. Its chemical name is retinol whose deficiency causes night blindness.

Carrot is the richest source of vitamin A. Spinach is a major source of iron which contributes to the level of haemoglobin concentration, beneficial for oxygen transportation.

Mango is a rich source of vitamin A among all the given fruits. It is also rich in vitamin C and E.

Vitamin A cannot be synthesized by the human body.

Vitamin A is the name of a group of fat-soluble retinoids, including retinol, retinal, and retinyl esters. Vitamin A is involved in immune function, vision, reproduction, and cellular communication. Vitamin A is critical for vision as an essential component of rhodopsin, a protein that absorbs light in the retinal receptors, and because it supports the normal differentiation and functioning of the conjunctival membranes and cornea. Vitamin A deficiency may lead to 'night blindness'. Vitamin A also supports cell growth and differentiation, playing a critical role in the normal formation and maintenance of the heart, lungs, kidneys, and other organs.

Vitamin A in humans is primarily obtained by conversion of beta-carotene, a pigment found in fruits and vegetables. Green vegetables are a good source for beta-carotene. If somebody takes green vegetables regularly, he gains sufficient amount of vitamin A. If he stops taking green vegetables, he could suffer from vitamin A deficiency, that may lead to the disease called 'night blindness'. However, vitamin A is found in many other foods also, so the person devoid of green vegetables does not necessarily suffer from night blindness.

Vitamin B₁₂ (Cobalamin) is a water-soluble vitamin. It contains a metallic ion cobalt. Its chemical formula is C₆₃H₈₈CoN₁₄O₁₄P. It functions as a cofactor for enzymes in the metabolism of amino acids and fatty acids, required for new cell synthesis, normal blood formation and neurological function. Its deficiency causes pernicious anaemia, nervous system abnormality etc.

Vitamin B₁₂ (Cobalamin) is a water-soluble vitamin. It contains a metallic ion cobalt. Its chemical formula is C₆₃H₈₈CoN₁₄O₁₄P. It functions as a cofactor for enzymes in the metabolism of amino acids and fatty acids, required for new cell synthesis, normal blood formation and neurological function. Its deficiency causes pernicious anaemia, nervous system abnormality etc.

Vitamin B₁₂ (Cobalamin) is a water-soluble vitamin. It contains a metallic ion cobalt. Its chemical formula is C₆₃H₈₈CoN₁₄O₁₄P. It functions as a cofactor for enzymes in the metabolism of amino acids and fatty acids, required for new cell synthesis, normal blood formation and neurological function. Its deficiency causes pernicious anaemia, nervous system abnormality etc.

Vitamin B₁₂ is also known as cobalamin which is water-soluble and remains stored in the liver for about 3-5 years. Vitamin B₁₂ is a co-factor of DNA synthesis and is in both fatty acid and amino acid metabolism. It is particularly important for the normal functioning of the nervous system via its role in the synthesis of myelin and in the maturation of developing RBC in the bone marrow. It contains cobalt (Co).