Vitamin A

Vitamin A


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VitaminA refers nutritional compounds that include retinoic acid,provitamin, retinol, beta-carotene among others. The vitamin hasseveral functions. It is essential for the development of good visionand unwavering immune system[ CITATION Mor10 l 1033 ].Goodsources of vitamin A include cheese, oily fish, low-fat spreads,milk, and eggs. An adult requires between o.6 and 0.7 mg of thevitamin in a day.

Thevitamin, in the form of retinoic acid, becomes an important factor ingrowth. The dominant form of vitamin A in the foods of animal originis ester that is converted to alcohol in the ileum. In its retinoicacid state, vitamin – A contributes to a healthy skin by aiding theswitching on the genes. The vitamin helps in the transformation ofkeratinocytes into mature cells. The vitamin further plays a veryimportant role during the skin therapy. It reduces the size of thesebaceous glands as well as the quantity of the excretions. Thisreduction facilitates the treatment of acne and other skin relateddisorders.

Thevitamin A deficiency affects almost a third of the global childrenpopulation. Many children in the developing countries have lost theirsight, and some have died due to the deficiency. A primary vitamin Adeficiency affects children and adults who fail to consume a goodamount of the vitamin from fruits and other foods[ CITATION Som08 l 1033 ].In the case of newborn infants, early weaning can increase the riskof vitamindeficiency. Chronic malabsorption of lipids is the major cause ofsecondary vitamin A deficiency. Other causes of secondary deficiencyinclude cigarette smoke and alcoholism[ CITATION Maq04 l 1033 ].

VitaminA deficiency can cause impaired vision and blindness. Such disordersare preceded by a series of changes. Firstly, the conjunctiva driesup while the mucus-secreting epithelium and normal lacrimal isreplaced by a keratinized epithelium. The buildup of keratin debrisfollows and finally the erosion of the corneal surface leading tototal blindness. The other effect of vitamin A deprivation is anincreased risk of meningococcal disease as well as ear infections.The deficiency of the vitamin can also cause enamel hypoplasia.

Anadequate supply of vitamin A is essential for the pregnant as well asbreastfeeding women. It is good to remember that postnatalsupplementation can not reverse deficiencies. It is also good to notethat an excess supply of the vitamin can cause birth defects.Therefore, one should not exceed the recommended measures.

Unlikethe other types of vitamins, vitamin A is fat soluble. Therefore,disposing any excesses from the body takes longer. Simply put, thevitamin can be toxic. Excessive consumption of the vitamin can causeanorexia, irritability, vomiting, headaches, hair loss, blurryvision, fatigue, etc. The toxic effects of vitamin A are evident indeveloping fetuses and newborns[ CITATION Hat99 l 1033 ].The doses used for acne treatment have been shown to be disruptingthe cephalic neural cell activities. The fetus is usually sensitiveto vitamin A toxicity. Moreover, an excessive intake of beta-carotenecan cause the discoloration of the skin. Many human and animalstudies have also proved that liver injury occurs when the alcoholconsumption is paired with high vitamin A doses.

Itis evident that vitamin A is very crucial to the health and wellbeingof any human being. Everybody should get all the vitamin A needed byeating a balanced diet. However, an excess of the vitamin can proveto be toxic. Therefore, one should note the amount of vitamin Apresent in any supplement. Pregnant women are advised to avoid a highintake of supplements containing vitamin A. Certainly, an adequatesupply of vitamin A is essential for good health. However, thequantities should be kept in check.


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Mora, J. R., Iwata, M., &amp von Andrian, U. H. (2010). Vitamin effects on the immune system: vitamins A and D take centre stage. HHS Public Access, 685-698.

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