05 Importance Of Vitamin A That Are Absolutely Lifechanging|

Importance of vitamin A

5 Top most Importance of Vitamin A In Human.

 

Vitamin A (retinoids) is the first of all vitamins which is required in very slight amount daily . There are lots of importance of vitamin A in our body.We will discuss them today. This vitamin refers to three preformed compounds that exhibit metabolic activity:

  1. The alcohol (retinol),
  2. The aldehyde (retinal or retinaldehyde) and
  3. The acid (retinoic acid).

Plants contain a group of chemical compounds. They are known as carotenoids. They can yield retinoids when metabolized in the body.  There are several hundred carotenoids exist in foods as antioxidants. Only a few have significant vitamin A activity. The most important of these is β-carotene. It possesses about one-sixth of vitamin A activity compared to that of retinol.

 

Importance of Vitamin A

They can yield retinoids when metabolized in the body. Although several hundred carotenoids exist in foods as antioxidants, only a few have significant vitamin A activity.

The most important of these is β-carotene. It possesses about one-sixth of vitamin A activity compared to that of retinol.  

Preformed vitamin A are retinol and retinyl esters. They  are mostly present in animal foods. Such as meat, dairy products, and fish. Provitamin A is beta-carotenoid. It is mostly present in colorful fruits and vegetables. Both forms of vitamin A must be converted to retinal and retinoic acid after absorption. This is essential to support biological processes.

Vitamin A is a fat-soluble vitamin. So, it needs oil or fat for proper absorption in gut. If you try to remove all oils and fats from your diet, you may will face vitamin A deficiency diseases. It also requires protein to bind (Retinol binding protein-RBP). The person who lacks of protein in diet severely, may face vitamin A deficiency. It is a common menifestation in protein energy malnutrition (PEM). 

How importance of vitamin A affect human life?

Vitamin A is essential for different kinds of functions such as good eye health, enough growth and differentiation, reproduction and maintenance of epithelial cells. Hence importance of vitamin A is very wide in our life.

It is recorded in the history that Hippocrates (about 500 B.C.) cured night blindness. He prescribed to the patients ox liver (in honey),
which is now known to contain high quantity of vitamin A.

1. Prevention of Eye Health: Night blindness & Xerophthalmia

Our eye retina structure depends on vitamin A. Retina has photosensitive rods and cone cells. They sense and adapt through dim light.

So, we can see things in low light at night or in place where light is very low.

This process (dark adaptation) prevents a disease called night blindness. Previously this disease was epidemic worldwide. It is a preventable disease.

The earliest symptom of vitamin A deficiency is Night blindness (nyctalopia). The person faces difficulty to see in dim light since the dark adaptation time is increased. Prolonged deficiency damages a lot of visual cells. This change is irreversible.

Severe deficiency of vitamin A leads to xerophthalmia. It means dryness in conjunctiva and cornea of eyes, and skin roughness (keratinization of epithelial cells). In conjunctiva of our eyes, white triangular plaques form. It is known as Bitot’s spots.

If xerophthalmia is not treated for a long time, corneal ulceration and degeneration occur in the eyes. It follows the destruction of cornea. It is Keratomalacia. It causes total blindness.

Adequate intake of vitamin A is necessary for the prevention of blindness. Hence importance of vitamin A is very high for best eye health.

Diet rich in vitamin A and carotenoids along with fat is essential to prevent night blindness.

Advanced Macular Degeneration (AMD) is a disorder that is usually develops after age 50 years.

An antioxidant supplement (including beta-carotene) helps to reduce the development of AMD and vision loss and blindness. Importance of vitamin A is extreme not only in early life but also in late life also.

2. Vitamin A for Healthy Reproduction

Several studies have shown that vitamin A and its precursors are crucial for normal reproduction.

Retinol and Retinoic Acid both are necessary for normal reproduction. They act like a hormone and regulate gene expression.  Retinoic Acid (RA) actively participates in proper genetic formation of sperms in both neonatal and adult testis.

Male genital tract construction and maintenance depends on Vitamin A. The whole process of sperm formation (spermatogenesis) is also dependable on adequate vitamin A in blood. 

 Thus, deficiency of vitamin A can lead to male infertility.

In female, vitamin A deficiency (VAD) reduces the egg quality.  It also affects on reproduction by impaired implantation of egg.

During pregnancy, the normal structure of fetus is dependent on vitamin A supply form mother. The organs, limbs, skin, skeleton, nervous system, hair, eyes all can develop well in the presence of vitamin A. In pregnancy period deficiency of vitamin A may result in malformation of baby. So, importance of vitamin A is very high for an optimum reproductive health.

Actually in term of fertility for both male and female importance of vitamin A is absolutely undeniable.

3.Importance of Vitamin A in Healthy Immune System

Vitamin A involves in production of glycoprotein through a series of reactions.

Glycoproteins are incredibly diverse and serve many functions in the body including cell aggregation and cell recognition.

Some provide structure e.g. Collagens, others are involved in immunity e.g. immunoglobulins (such as IgG). They produce mucins which are secreted into mucus of the respiratory and digestive tracts. These specific mucins allow mucus to serve as an effective lubricant.

The mucous barriers in human eyes, lungs, gut and genitals help trap bacteria and other infectious agents.

Glycoproteins also function as a structural component of several hormones. Follicle Stimulating Hormone (FSH) is one example. This hormone involves in development, growth, puberty, and reproduction.

Vitamin A is also essential for the production and proper function of white blood cells.

They help capture and clear bacteria and other pathogens from your bloodstream.

The red blood cell recognition is possible for the presence of glycoprotein in its cell surface.

Vitamin A deficiency increases the chance of respiratory and diarrheal infections.

The skin becomes rough and dry. Keratinization of epithelial cells of gastrointestinal tract, urinary tract and respiratory tract is very common. This leads to increased bacterial infection.

Vitamin A deficiency  also leads to the formation of urinary stones.

Thus vitamin A deficiency reduces the quality of healthy immune system.

The mortality rate is high in vitamin A deficient Infants, young children and pregnant women. Particularly In populations where vitamin A availability from food is low.

The importance of vitamin A is very wide in maintaining our health.

4. Importance of Vitamin A in Cancer And Chronic Diseases Prevention.

Vitamin A play a crucial role in regulating the differentiation and proliferation of epithelial cells. They are potent inducers of programmed cell death that are beyond repair (apoptosis).

The carcinogen-induced damage to DNA of regulatory genes causes the development of cancers. Most of the results from experimental studies indicate that retinoids are effective in preventing or suppressing cancers. 

Carotenoids has highly reactive conjugated double bonds. They act as free radical traps or antioxidants. In this way they play an important role in the prevention of  cancers. Among all carotenoids, beta-carotene is most strong antioxidant. They are mainly found in all fruits and vegetables specially in colored ones.

Higher vegetables and fruits in daily food habit lowers the risk of several cancers. It is also very beneficial to prevent heart diseases.

It is also the importance of vitamin A to prevent heart diseases.

Lower dietary vitamin A intake results in a higher risk to develop cancer.

Daily consumption of fruits and vegetables is proved that it helps to reduce the risk of developing chronic diseases.

Specially cancer is strongly prevented with regular intake of vitamin A and beta-carotene. Particularly the cancer of the esophagus, oral cavity, pharynx, larynx, stomach, colon, and rectum. In case of prevention of all kinds of cancers importance of vitamin A is utmost high.

5. Other Health Benefits of Vitamin A

Although vitamin D, calcium and protein are the key nutrients in growth and maintenance of bone health. But vitamin A is also needed to maintain a healthy bone structure.

Lower blood levels of vitamin A increases the risk of bone fractures.  The people with healthy levels of vitamin A are in lower risk of bone fractures.Along with all other health benefits importance of vitamin A is also high in case of good bone health.

Vitamin A Toxicity

The importance of vitamin A in our life is vey high. This vitamin is fat soluble so we cannot excrete it through urine. So, we have to be aware of vitamin A toxicity.

Excessive consumption of vitamin A leads to toxicity. The symptoms of hypervitaminosis A include

  • dermatitis raised intracranial tension,
  • enlargement of liver,
  • skeletal decalcification,
  • tenderness of long bones,
  • loss of weight,
  • irritability,
  • loss of hair,
  • joint pains etc.

Elderly people are more prone to vitamin A toxicity. So overdoses must be avoided.  

Total serum vitamin A level (normal 20–50 micro g/dl) is elevated in hypervitaminosis A. Higher concentration of retinol increases the

synthesis of lysosomal hydrolases. The manifestations of hypervitaminosis A are attributed to the destructive action on the cell membranes. Importance of vitamin A level maintaining is high to prevent toxicity.

Food Sources

   
Food mcg RAE
per serving
Percent
DV*
Beef liver, 3 ounces 6,582 731
Sweet potato, 1 whole 1,403 156
Spinach, boiled, ½ cup 573 64
Pumpkin pie, packed, 1 piece 488 54
Carrots, raw, ½ cup 459 51
Herring, Atlantic, pickled, 3 ounces 219 24
Ice cream, French vanilla, soft serve, ⅔ cup 185 21
Milk, skim, with added vitamin A and vitamin D, 1 cup 149 17
     

Cheese, partly skimmed, ½ cup

133 15
Peppers, sweet, red, raw, ½ cup 117 13
Mangoes, raw, 1 whole 112 12
Breakfast cereals, fortified with 10% of the DV for vitamin A, 1 serving 90 10
Egg, hard boiled, 1 large 75 8
Black-eyed peas (cowpeas), boiled, 1 cup 66 7
Apricots, dried, sulfured, 5 apricots 63 7
Broccoli, boiled, ½ cup 60 7
Salmon, cooked, 3 ounces 59 7
Tomato juice, ¾ cup 42 5
Yogurt, low fat, 1 cup 32 4
Tuna, light, canned in oil, drained solids, 3 ounces 20 2
beans, canned, plain or vegetarian, 1 cup 13 1
squash, boiled, ½ cup 10 1
Chicken, breast meat, roasted, ½ breast 5 1
Pistachio nuts, dry roasted, 1 ounce 4 0
*DV = Daily Value.

The DV for vitamin A is 900 mcg RAE for adult requirement and children of 4 years and older.

  • 1 mcg RAE = 1 mcg retinol,
  • 2 mcg beta-carotene from supplements,
  • 12 mcg beta-carotene from foods,
  • 24 mcg alpha-carotene,
  • or 24 mcg beta-cryptoxanthin.

Foods those contain 20% or more of the DV of vitamin A are considered to be high sources of a nutrient. But the foods containing lower percentages of the DV also contribute to a healthful diet.

Final Thoughts

We may take vitamin A and carotenoids from foods regularly; we need to keep in mind that this vitamin needs a carrier to proper absorption and use in our body. Most important carriers are fats and oils and protein. Here first-class protein is the primary choice, even second-class protein may help. So, our diet must be rich in all kinds of foods that can meet our each type of nutritional needs.   

 

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