Importance of Vitamin A

Importance of Vitamin A
Introduction:
Vitamin A is a fat-soluble vitamin abundantly found in foods of animal origin like cod liver oil, fish liver oil, liver, milk, butter and eggs etc. it is also known as retinol and is a pale-yellow color crystalline substance. Vitamin A is important for the normal vision, the immune system and reproduction. It also keeps the heart, lungs, kidneys and other organs to work properly. As vitamin A id fat soluble so it is stored in the body where the fat deposits are found for later use. Most of the vitamin A in your body is stored in your liver. In this article, the discussion will be about vitamin A, its importance, sources and deficiency issues.
Types of Vitamin A:
There are two different types of vitamin A. These are:
Preformed vitamin A
Pro-vitamin A
Preformed vitamin A:
It includes the retinol and retinyl esters and is found in animal products such as dairy products, poultry, fish and meat.
Pro-vitamin A:
It includes the carotenoids found in plants that are fruits and vegetables e.g carrots, spinach, tomatoes and mangoes etc. The most important of these carotenoids with respect to vitamin A is B-carotene. When foods containing B-carotene are eaten, it is converted into the active form of vitamin A that is retinol. B-carotene is the most common type of vitamin A found in foods and dietary supplements.
Importance of Vitamin A:
Vitamin A has many vital roles to play in our body. It performs many functions. These include:
Functions:
Vitamin A is an anti-infective vitamin and thus can help prevent infection.
It is also essential for the growth and metabolism of all body cells.
It play its role in the formation of rhodopsin that is a pigment found in the retina and helps to adjust the vision in the dark thus preventing night blindness.
It also helps to keep the skin smooth.
It provides resistance against infections to the linings of mouth, nose, throat, and digestive tract.
It also strengthens the mucosal epithelium.
Vitamin A helps maintain surface tissues such as skin, stomach, lungs, bladder, intestine and inner ear etc.
It also supports healthy male and female reproduction and fetal development.
It supports immune function by supporting the growth of T-cells.
Pro-vitamin A such as B-carotene has antioxidant properties. So these carotenoids show their antioxidant property by fighting to the free radicals and releasing the oxidative stress from the body. Diets high in carotenoids thus works to prevent diseases like diabetes, CVD’s etc
Some studies have shown that the people who take diets rich in carotenoids are at the lower risk of developing cancer such as bladder, breast and ovarian cancer. But the supplements of vitamin A have not been seen effective in treating cancer.
In the people with growing age or getting aged, there is a problem with the loss of central vision. Vitamin A supplements have found effective in delaying this loss of vision with the growing age.
Food sources:
Vitamin A can be found in many food sources. Following foods contain rich amounts of vitamin A precursors that forms the preformed type of vitamin A:
Trout fish
Beef liver
Butter
Cod liver oil
Chicken liver
Cheddar cheese
salmon
Liver sausage
Egg yolks

The foods which are rich in the B-carotene precursors of pro-vitamin A are:
Carrots
Kale
Cabbage
Dandelion greens
Spinach
Red peppers
Parsley
Butternut squash
Collard greens
Recommended doses of vitamin A:
The doses of vitamin A you need depend upon your age and reproductive status. The recommended doses of vitamin A are:
Over the age of 14 years the recommended doses are 700 mcg and 900 mcg (microgram) of Retinol Activity Equivalents (RAE) that is the unit for vitamin A measurement.
For lactating women the range should be between 1200 and 1300 RAE.
Deficiency diseases:
The deficiency of vitamin A causes:
Night blindness (lack of vision during night)
Skin keratinization (formation of flakes on the skin)
In children its deficiency causes retarded growth.
Its deficiency causes Xerophthalmia in young children and pregnant ladies.
Side-effects of high doses:
The overdoses of this vitamin have significant harms on the human health:
Getting too much preformed vitamin A causes:
Dizziness
Nausea
Headache
Coma and;
Even death
In pregnant ladies, it’s over consumption causes birth defects in their babies.
Overdoses of pro-vitamin causes:
Your skin colour turned into yellow orange but it is a harmless condition.
Its high intake doesn’t cause birth defects and other ailments like preformed vitamin A.
Conclusion:
So, in a nutshell vitamin A is essential for normal growth and body metabolism. You must take it in your diet within appropriate amount otherwise complications may arise.