Vitamin- A is a group of compounds that perform many vital functions like maintaining a proper vision, improving bone growth and other cellular activities like reproduction, division, and differentiation. The fat-soluble vitamin-A is present only in the food of animal origin and its provitamin carotenoids are found in plants. Vitamin- A plays a vital role in growth and development of human cells, controlling the immune system by preventing infections and by activating white blood cells (WBC) that destroys harmful pathogens. They are also associated with formation and protection of healthy surface linings areas of the respiratory tract, intestinal tracts and urinary tracts from bacteria and other foreign organisms by causing infections. Vitamin- A helps skin and mucous membranes to function as a barrier to bacteria and viruses. This compound is often referred as the antixerophthalmic factor or the bright eyes vitamin, on an account of its established role in the visual process.
DISCOVERY OF VITAMIN – A
It has been observed and recorded that “Hippocrates of Kos” an ancient Greek (about 500 Bc) cured night blindness by prescribing his patients to use vitamin- A in their diet. Later in the year 1917 “McCollum” and “Davis” found the fat-soluble factor in vitamin- A. The activity of vitamin- A was discovered by a nutrition scientist named “Christine Stumbock” in the year 1919. Later in the year 1931, the structure of vitamin A was determined by “Karrer” and its synthesis was achieved in the laboratory by “Kuhn” and “Morris” in the year 1937.
DIETARY SOURCES OF VITAMIN- A.
Vitamin A is found naturally in many foods and is obtained by both from the plant and animal source.
- The preformed Vitamin- A is the source of vitamins which are obtained from the animals. These are absorbed in the form of retinol. Retinol is the most usable and active form of vitamin- A. Source includes liver, fish, poultry, whole milk and other animal products.
- The provitamin- A carotenoid is the source of vitamins which are obtained from the plant source that includes colourful fruits and vegetables like green leafy vegetables and yellow vegetables, such as broccoli, carrots, squash, etc. Fruits include mangos, cantaloupe, orange, apricots, etc.
BIOCHEMICAL FUNCTIONING OF VITAMIN- A.
Vitamin- A is necessary for a variety of functions such as proper vision, healthy immune system, and maintenance of epithelial cells. Vitamin- A also plays a vital role in regulating and synthesis of proteins and transferrin.
DEFICIENCY OF VITAMIN- A.
The deficiency of vitamin- A is not instant, since the hepatic located in the abdominal cavity, store’s these vitamins, which can meet the body requirements for 2 to 4 months. The deficiency of vitamin- A is mainly related to problems with eyes (vision), skin and growth. As per the medical records, these deficiencies are mainly seen in the children under the age of five.
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