Vitamin-A

Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids (most notably beta-carotene). Vitamin A has multiple functions: it is important for growth and development, maintaining the immune system and good vision. Vitamin A is needed by the retina of the eye in the form of retinal, which combines with protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision. Vitamin A also functions in a very different role as retinoic acid (an irreversibly oxidized form of retinol), which is an important hormone-like growth factor for epithelial and other cells. In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to retinol (chemically an alcohol) in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal. All forms of vitamin A have a beta-ionone ring to which an isoprenoid chain is attached, called a retinyl group. Both structural features are essential for activity.

Introduction

The vitamin A group comprises retinol, retinal, retinoic acid and several provitamin A carotenoids. Vitamin A has multiple functions: it is important for growth and development, for the functioning of the immune system, and for good vision. Retinol is converted in the body to retinal and then to retinoic acid; each form has different functions. Retinol is also stored in the liver; when needed, it travels through the blood bound to a transport protein called retinol-binding protein.

Vitamin A has multiple functions: it is important for growth and development, for the maintenance of the immune system and good vision.

Vitamin A is an essential vitamin that has multiple functions: it is important for growth and development, for the maintenance of the immune system and good vision.

Vitamin A helps in the production of sebum (the oily substance secreted by skin glands) and thus helps prevent dryness of hair and skin. The mucous membranes lining our respiratory tract are protected against harmful bacteria by vitamin A.

Vitamin A is needed by the retina of the eye in the form of retinal, which combines with protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision.

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Vitamin A also functions in a very different role as retinoic acid (an irreversibly oxidized form of retinol), which is an important hormone-like growth factor for epithelial and other cells.

Retinoic acid also functions in a very different role as retinoic acid (an irreversibly oxidized form of retinol), which is an important hormone-like growth factor for epithelial and other cells. Retinoic acid acts by binding to specific intracellular receptors, causing the activation or repression of genes that regulate cell proliferation, differentiation and development.

In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to retinol (chemically an alcohol) in the small intestine.

In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to retinol (chemically an alcohol) in the small intestine. Retinol can be stored by the liver for several months and its concentration reflects that of dietary intake. Retinol is transported through blood plasma as a complex with other lipoproteins (plasma retinol-binding protein or RBP).

Retinoid X receptors (RXRs), pregnane X receptors (PXRs), peroxisome proliferator-activated receptors α and γ (PPARsα/γ), liver receptor homolog 1 (LRH1) and peroxisome proliferator activator receptor δ are nuclear receptors that regulate the expression at the cellular level of genes involved in lipid metabolism.

The retinol form functions as a storage form of the vitamin and can be converted to and from its visually active aldehyde form, retinal.

Retinol, the storage form of vitamin A, can be converted to retinal and then to aldehyde. The Retinal is a visual pigment that absorbs light, allowing your brain to process it and create images.

Retinal is found in the rods and cones of your eye (photoreceptors), which allow you to see in dim lighting conditions like nighttime or inside a dark room. It also enables you to see colors because each cone cell contains one type of photoreceptor with its specific color receptor molecule (such as red, blue or green).

All forms of vitamin A have a beta-ionone ring to which an isoprenoid chain is attached, called a retinyl group.

The retinyl group is a carboxylic acid group. It is attached to the beta-ionone ring, which forms part of the vitamin A molecule.

Both structural features are essential for activity.

A retinoic acid is a hormone-like form of vitamin A that plays an important role in human growth and development. It also mediates epithelial-cell differentiation and keratinization, two processes involved in skin repair. Retinoic acid can be found in all animal sources of vitamin A, including liver and fish oils.

Vitamin A helps keep a body healthy

Vitamin A helps keep a body healthy. Without it, you may get sick more often and have trouble seeing in the dark. It also helps keep skin and hair healthy.

People who don't get enough vitamin A may have poor night vision, dry skin that cracks or peels easily or rough hair that falls out. They also might have problems with their growth or development as children (including slow bone growth).

Conclusion

In summary, this article discussed what vitamin A is, why it is important for the body and some of its important functions. I hope that you have a better understanding of how this nutrient affects your health and well-being.

Conclusion

Vitamin A is a potent antioxidant and an essential vitamin that helps keep a body healthy by promoting normal growth, repairing tissues, and protecting against infection. It is one of several antioxidants that help prevent damage to your cells and support the immune system. It is important for you to get enough Vitamin A in your diet because this compound can be toxic at high doses.

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