Vitamin A is major fat-soluble pale-yellow vitamin. This is a primary alcohol derived from carotene. This has two levels of function in the body. The first occurs throughout the visual cycle in the retina, while the second occurs across the body to sustain cell development and health.
This is necessary for healthy development and growth. it supports for body tissue development and repair as well as infection resistance. Insufficient amounts of this vitamin has an extensive effect on epithelial cell growth and differentiation throughout the body.
Types of Vitamin A
It is categorized into two forms. Retinoid and Carotenoid
Retinoid: Only animal foods contain retinoids. There are three different types of retinoids. Retinol, an alcoholic form of vitamin A, is the first form. Creams, lotions, and serums for the skin frequently include retinol. It may be used to treat acne and has anti-ageing properties.
The second type of retinoid, the Aldehyde form of vitamin A, is retinaldehyde, which may be converted into retinol and retinoic acid.
It is used to boost collagen synthesis and encourage healthy cell renewal. Additionally, it aids in minimizing the skin’s wrinkles and fine lines.
Retinoic acid is the third retinoid form. It is crucial for both adult health and good embryonic development. Additionally, it is used to treat conditions including ichthyosis, psoriasis, acne, and skin cancer.
Carotenoid
The number of carotenoids in existence is around 600. which are separated into the groups of carotenes and xanthophylls.
Xanthophyll is specially identified for its pigmentation. For example, corn, peas, spinach, pumpkin, and eggs.
Whereas carotenes are photosynthetic pigments important for photosynthesis. It does not have an oxygen atom. Carotenes are responsible for the color pigmentation of fruits and vegetables like carrots, melon, and sweet potatoes.
Functions of vitamin A
Vitamin A serves a variety of functions in the human body. here are 6 main functions of it.
Maintain the health of the Epithelial Tissues
Tissues known as epithelial cells cover the outside of the body. These are specialist tissues with a protective epidermis on the outside, a tough outer coating, and a secretory mucous membrane inside. These epithelial cells, which are found on the interior and exterior surfaces of the lungs, gut, stomach, bladder, and eyes, benefit from vitamin A in order to remain healthy.
To build immune response
Normal immunological responses and control depend on vitamin A. Numerous epithelial tissues serve as vital infection barriers. It specifically aids in maintaining the lymphocyte pool. Additionally, vitamin A contributes to T-cell-mediated responses. Retinoids can influence several immune response components, such as the generation of immunoglobulin.
Important for vision perception
A retinal form of vitamin A is responsible for the perception of visual aids. Also, the rhodopsin pigment is responsible for night vision. Insufficient vitamin A leads to low rhodopsin pigments, which affect night vision.
Important for normal growth and cellular differentiation
In humans, vitamin A, particularly retinoic acid, is crucial for cell growth and division, especially during fetal development. It is well-known that retinoic acid regulates the growth and development of tissues in the musculoskeletal system in a manner equal to that of hormones.
Energy Balance
It has recently been demonstrated that retinoic acid transcriptionally regulates an enzyme in mitochondria that is responsible for the local synthesis of energy as heat.
Protection of the cells against free radicals
Numerous illnesses, including heart disease and some forms of cancer, have been connected to free radicals. Additionally, the body’s cell membranes and structure are harmed by these free radicals. To prevent cell deterioration, vitamin A functions similarly to an antioxidant.
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Sources of Vitamin A
One major form of the vitamin retinol is obtained only from animal food. Vitamin A is abundant in animal liver.
It founds nearly exclusively in animal products, including human milk, meats, liver and fish liver oils, egg yolks, and whole milk ,butter, ghee, milk, curds and dairy products.
Provitamin A, or beta-carotene, is found in plants that have bright yellow or orange pigmentation, like papaya, orange, and pumpkin. Also, dark green leafy vegetables like spinach, dill leaves, fenugreek, and amaranth leaves are rich in beta-carotene.
Deficiency of Vitamin A
There are several phases of vitamin A deficiency. insufficiency of this vitamin causes conjunctival xerosis, a dry eye condition. it also affects the cornea which can also melt and wrinkle. A long-term deficit causes night blindness.
People who are vitamin A deficient may have skin issues like dryness, itching, and scaling. It is crucial for improving immunity. People who lack it are more prone to disease.
It has an impact on the way the children’s bones develop. Children that are deficient in this vitamin experience stunted development.
Recommended Dietary Allowance
For men and women, the Recommended Dietary Allowance (RDA) is 700 μg and 900 μg of retinol activity equivalents (RAE) per day, respectively.
Children need between 300 and 400 μg RAE of vitamin A per day.
Pregnancy raises the demand for vitamin A to 800 μg RAE/day. An extra 350 μg of RAE per day is needed throughout the breastfeeding period.