Vitamins play an integral role in our good health and better life. In an era in which diseases and deficiencies often bother people, it is vital to know the usefulness of vitamins in our diet for a better lifestyle.
There are different vitamin requirements for each organism. For example, humans have to get vitamin C from their diet – while dogs can produce vitamin C by themselves as per their requirement.
The human body needs different amounts of each vitamin to stay healthy.
In this article, we’re going to talk about Vitamin A; we will explain what Vitamin A is, what it does, which foods are good sources of it, what vitamin A deficiency is, and how vitamin A deficiency affects your overall health.
So without further ado, let’s get started:
What is Vitamin A?
Vitamin A is an essential vitamin that is necessary for the body to grow and develop properly. Vitamin A is often considered a singular nutrient but is the name of a group of fat-soluble retinoids, including retinol, retinal and retinyl esters.
There are two types of vitamin A: retinoids (preformed vitamin A)- which comes from animal sources, and carotenoids (provitamin A)- which comes from plant-based sources.
Preformed vitamin A retinoids include retinol, retinal and its esterified form, retinyl ester.
Provitamin A carotenoids include beta-carotene, alpha-carotene and beta-cryptoxanthin. And of which the most important provitamin A carotenoid is beta-carotene.
Retinol is responsible for healthy eyesight, strong bones and glowing skin but is found only in animal-based foods.
But, what about vegetarians?
Well, you don’t need to worry. Your body is capable of converting both forms of vitamin A into the retina and retinoic acid, which are active forms of vitamins.
Vitamin A Benefits:
Vitamin A contributes to various bodily functions and helps prevent many problems. Consuming the required levels of vitamin A:
- is essential to vision and eye health.
- is vital for both male and female reproduction.
- boosts your immune system.
- helps in the growth of all bodily tissues, including skin and hair.
- contributes to lowering cancer risk.
Foods Rich in Vitamin A:
Preformed vitamin A exists in animal foods, and provitamin A carotenoids are found in plant foods. Preformed vitamin A is absorbed and used by your body more easily than provitamin A carotenoids.
For this reason, people who are vegetarian should be cautious about getting enough carotenoid-rich foods.
Typically, foods rich in high-fat content have a large proportion of retinol.
Foods high in preformed vitamin A are:
- egg yolks
- organ meats, such as liver
- cod liver oil
- fatty fish, such as salmon, tuna and herring
- cheddar cheese
Foods high in provitamin A are:
- sweet potato
- red peppers
- swiss chard
- turnip greens
- collard greens
- dandelion greens
- green peas
Vitamin A Recommended Intake:
According to the dietary reference intake (DRI) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies, the recommended daily amount (RDA) of vitamin A by age are as follows:
|0–6 months*||400 mcg RAE||400 mcg RAE|
|7–12 months*||500 mcg RAE||500 mcg RAE|
|1–3 years||300 mcg RAE||300 mcg RAE|
|4–8 years||400 mcg RAE||400 mcg RAE|
|9–13 years||600 mcg RAE||600 mcg RAE|
|14–18 years||900 mcg RAE||700 mcg RAE||750 mcg RAE||1,200 mcg RAE|
|19–50 years||900 mcg RAE||700 mcg RAE||770 mcg RAE||1,300 mcg RAE|
|51+ years||900 mcg RAE||700 mcg RAE|
*Adequate Intake (AI), equivalent to the mean intake of vitamin A in healthy, breastfed infants.
Vitamin A Deficiency:
It is necessary to ensure that you get the required amount of retinol or vitamin A for a healthy body. In fact, not consuming the required amount can lead to several deficiencies.
Because vitamin A is fat-soluble, it is stored in body tissues for later use.
The majority of vitamin A in the body is preserved in the liver as retinyl esters. These esters subsequently break down into all-trans-retinol, which binds to the retinol-binding protein (RBP), which enters your bloodstream. The body then starts using it after it enters the bloodstream.
However, when your body does not get the required amount of vitamin A; It appears as various deficiencies in your body.
Vitamin A deficiency is rare in the United States, but it is common in developing countries. If it happens, it can lead to severe health complications, which may include:
- eyes, and skin related problems.
- increased risk of dying from infections like measles and diarrhoea.
- risk of anaemia and death in pregnant women.
Signs and Symptoms of Vitamin A Deficiency:
Having complete information about the deficiency at the beginning can reduce or even prevent damage from it. Knowing and identifying the signs and symptoms of deficiency is very important for a speedy recovery. Early symptoms of vitamin A deficiency may include:
Changes in the Eye:
Early signs of vitamin A deficiency often appear in the eyes. The symptoms may include itching, burning sensation, swollen eyelids, and dry eyes.
Apart from this, in some cases, people also suffer from night blindness, in which they experience poor vision at night or in a dim light environment.
Xerophthalmia, a progressive eye disease in which a person has to suffer dryness of conjunctiva and cornea of the eye, is also known to be caused by vitamin A deficiency.
Changes in the Skin:
As you know, the skin is the largest organ in the body, with a total area of about 20 square feet. And, your skin is the organ that first exposes your internal health.
Vitamin A deficiency can cause many skin problems, which may include dry skin, broken fingernails, and acne.
Apart from this, many people with Vitamin A deficiency suffer eczema, a condition that causes dry, itchy and inflamed skin.
Vitamin A Risks:
Anything in excess is very harmful. Similarly, taking too much vitamin A, whether through diet or supplementation, can also be dangerous.
Vitamin A Toxicity:
Vitamin A contributes to many functions in the body, but consuming too much performed vitamin A can lead to vitamin A toxicity, or hypervitaminosis A.
Symptoms of vitamin A toxicity can include:
- changes in the colour of the skin
- cracked skin on the fingers
- ectropion- when your lower eyelid turns or sags outward
- dry lips, mouth, and nose
Long-term overuse can lead to:
- bone pain
- liver damage
- changes in the nervous system
- high cholesterol level
- vomiting, headaches, confusion
A healthful, balanced diet has a little chance to lead to toxic levels of vitamin A. While, the high risk of overuse is with supplements. So it is not advised to take more than the RDA of vitamin A supplements unless your doctor recommends it.
Also, people who consume a large quantity of alcohol or suffer from kidney or liver disease should not take vitamin A supplements without consulting a doctor. Alcohol accelerates enzymes activity in the body, which results in retinol breakdown. In addition, alcohol also interferes with the conversion of carotenoids into retinol.