Benefits Of Vitamin A Beyond Eyesight

Benefits Of Vitamin A Beyond Eyesight

Overview:

Vitamin A comprises a group of fat-soluble retinoids ( retinol, retinal, and retinyl). It functions as an essential micronutrient aiding in regulating tons of metabolic processes in the body. As it falls in the category of fat-soluble vitamins, thus it is inevitable to take mindful amounts of vitamin A. Fat-soluble vitamins are not excreted from the body as water-soluble vitamins (B & C). The excess amount of Vitamin A ( and all other fat-soluble vitamins) can accumulate in the body leading to toxicity. Hence it is imperative to intake only the recommended amounts of vitamin A.
In this article, you will get to know in detail how vitamin A benefits the body beyond the common perception of it being used for improving eyesight only.

PRINCIPLE FORMS OF VITAMIN A:

Vitamin A exists in the following two principle forms:
1. Active Form ( Retinol, Retinyl esters)
2. Precursor form ( Provitamin A carotenoids, e.g. B-carotenes)

ACTIVE FORM:

The active form of the vitamin is retinol and is mainly obtained from animal sources such as dairy, fish, and liver. Animal liver contains a high quantity of vitamin A in active form as it is stored here; thus, the liver is a rich source of retinol (The active form of vitamin A). The body can use retinol without the need for conversion.

PRECURSOR FORM:

Vitamin A obtained from plant sources occurs in the precursor form, i.e. Carotenoids such as B-carotenes. The inactive form can not be used by our body directly; hence it is converted into the active form in the intestinal cells of human beings. Fruits and vegetables, especially carrots, are a rich source of carotenoids and are beneficial in providing high Vitamin A content.

FUNCTIONS OF VITAMIN A:

Vitamin A has multiple functions in the human body, and it adds to the overall maintenance of health. Some of the critical roles of vitamin A in the body are as follows:

VISION:

The most prominent function of vitamin A is its role in vision. Vitamin A helps to improve night vision, and an adequate quantity of retinol is required to maintain eyesight. In the eyes, the retinal form of Vitamin A combines with a protein called Opsin to form rhodopsin which is a light receptor protein that helps in night vision. It functions in color vision and particularly in night vision.

IMMUNE FUNCTION:

Vitamin A supports immune function and helps boost immunity, preventing delayed immune responses. Hence, a sufficient amount of vitamin A is essential for regulating and strengthening immune functions.

CELL GROWTH:

Vitamin A also promotes the growth of specific epithelial cells, which is why it helps improve the skin. A retinoic acid is a form of vitamin A with a hormone-like growth factor that helps in the production and growth of epithelial cells.

FORMATION OF PROTEINS AND GENE TRANSCRIPTION:

A retinoic acid is a necessary form of vitamin A that helps in the transcription of genes. The retinol is entered into the cells, and oxidation occurs, resulting in the formation of retinaldehyde with the action of enzymes called retinol dehydrogenases. Further oxidation occurs, and acid is formed. Retinoic acid binds to the nuclear receptors, and the retinoic is completed from the upper part of the small intestine.
The process starts when we engulf a food containing Vitamin A from a plant or animal source. Vitamin A goes without metabolic breakdown from the mouth into the stomach. When the food is broken down into simple substances in the stomach, the fatty food containing Vitamin A is further broken down into small fat globules. These fat globules called micelles then enter the small intestine, in which further breakdown occurs. For digestion and breakdown of these fat molecules, various enzymes from the pancreatic duct and small intestine cells are released along with Bile that emulsifies the fat molecule and converts it into a small fat molecule called chylomicrons capable of diffusing from the small intestine walls. From the intestinal mucosa, chylomicrons are absorbed by the walls of the small intestine.
Then starts the transport of Vitamin A, during which the chylomicrons containing Vitamin A moves from the small intestine to the lumen of the lymphatic system (because of its large size, which cannot enter blood capillaries near the small intestine). The lymphatic system takes chylomicrons to the liver, breaks down fat, and transports it to the blood. From blood, the chylomicrons are transported to body adipose tissues. Fatty tissues have an enzyme called lipoprotein lipase. When this enzyme acts on chylomicrons, Vitamin A is released and provided to blood tissues from where it is taken to the targeted region with blood.

Cell Differentiation and Growth:

Vitamin A plays an essential role in mRNA formation and is compulsory for specific protein synthesis. It further helps in cell differentiation and growth. So, it has a significant role in skin and hair growth.

Vitamin A has a significant role in vision. Deficiency or malabsorption of Vitamin A causes poor vision and eventually night blindness. Vitamin A has retinyl esters that the liver converts to the retinal. Retinal combines with opsin and forms rhodopsin which is the primary nutrient required by the retina of the eyes.

VITAMIN A-RELATED DISORDERS:

DEFICIENCY OF VITAMIN A:

Vitamin A deficiency is a leading cause of several health complications, and it disrupts normal body functioning. Deficiency of vitamin A causes:

NIGHT BLINDNESS:

When vitamin A is insufficient in the dietary intake, there is a lack of retinol necessary to form rhodopsin ( light receptor protein). Night vision is affected because the required quantity of rhodopsin protein is not formed. It leads to blurry vision at night and the ultimate night blindness.

XEROPHTHALMIA:

It is a condition that causes abnormal dryness of the conjunctive corners and cornea of. It mainly occurs due to a deficiency of vitamin A.

BITOT’S SPOTS:

It is a disorder that causes the formation of yellow foamy lesions in the eye and can even damage the cornea leading to blindness. This disease is prominent, particularly in males, and is named after the scientist Charles Bitot.

TOXICITY OF VITAMIN A:

As the deficiency of vitamin A causes severe problems, excessive intake can also lead to toxicity and malfunctioning of the body. When vitamin A is stored excessively, it affects immune functions due to intracranial pressure. This abnormal pressure on the nerves disrupts the functioning of the choroid plexus and hence disturbs the immune response. It can cause:
1. Dizziness
2. Headaches
3. Fatigue
4. Comma and fatal conditions

CONCLUSION:

Concluding all the facts stated above, it is evident that vitamin A plays an essential role in maintaining and regulating body functions. It is critical to fulfilling the RDA of vitamin A through diet and supplements ( according to the doctor’s recommendation). The intake of vitamin A should be monitored mindfully as the deficiency or excess can lead to severe complications, as mentioned above. If you want to learn more about the essential nutrients for the body and the importance of wellbeing, check our website asap!

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