The idea that you must eat your carrots to have night vision is as ancient as the hills. Unlike other myths passed down through generations, this holds a grain of truth. Beta-Carotene, a compound that gives carrots their vibrant orange pigment, is transformed into Vitamin A by enzymes when we eat them. This nutrient has been scientifically proven to maintain our hawk-like vision.
What is Vitamin A?
Vitamins are a widely discussed subject in the domain of nutrition. Every child is taught that vitamins are essential to a well-balanced diet. They are vital nutrients without which many biological processes would not run smoothly. Out of the 13 necessary vitamins, very few are produced by the body itself. Hence, we depend on the food we consume to maintain sufficient levels of vitamins in our bodies. Each vitamin plays a different role in our physiological functions. “Vitamin A is a fat-soluble vitamin essential in cell development, metabolism, immune competency, vision, and reproductive functions.”
Vitamin A exists in two variations or forms. Vitamins present in Animal-based sources like beef (liver) are called preformed Vitamin A. In such sources, Vitamin A exists in its natural form (retinol and retinyl esters) and is easily absorbed. Vitamin A present in plant-based sources is called Proformed Vitamin A. This form of Vitamin A (carotenoids) is highly inactive and has to be broken down into active Vitamin A (retinol) by intestinal enzymes through a process called cleavage.
What does Vitamin A do?
1. Preserves Eye Health
Vitamin A is popularly known to play a pivotal role in preserving our eyesight. It is essential for the production of Rhodopsin, a visual pigment present in the rod cells of our retina. This pigment, also known as visual purple, acts as the driving force for our vision in dim light or at night.
As we grow older, our visual acuity slowly tapers off. This is called Age-Related Macular Degeneration (AMD). Studies have shown that a healthy intake of Vitamin A can prevent the quick onset of AMD.
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2. Strengthens the immune system
Vitamin A is integral to developing and maintaining tissues that line our eyes, nose, throat, lungs, gut, and genitals. These tissues are our body’s natural first line of defense against disease-causing microorganisms.
Vitamin A also aids in the production of B-cells and T-cells by the bone marrow. These lymphocytes are responsible for secreting antibodies to fight and kill any pathogen that invades our body. Without Vitamin A, our immune system is bound to weaken, and we would be easily susceptible to several diseases.
3. Removes Acne
Although researchers are still in the dark on how exactly vitamin A contributes to the removal of acne, it has been observed that people with Vitamin A deficiency develop follicular hyperkeratosis, a condition in which the hair follicles on the skin produce extra keratin. This is one of the key causes of acne.
Consuming foods high in Vitamin A is also said to nourish and give a glow to the skin.
4. Other Benefits of Vitamin A
Although Vitamin D is mainly responsible for the proper growth of bones, Vitamin A is also necessary for good bone health. Fortified foods with Vitamin A and hemoglobin adjuncts prevent the risk of anemia by stimulating the production of Iron. Studies have also shown that smokers who consumed fruits and vegetables with carotenoids (Vitamin A) had a reduced risk of lung cancer. It is also important for reproductive health.
Vitamin A Deficiency (VAD)
When your body has insufficient amounts of Vitamin A, you are considered Vitamin A deficient. This is usually detected with a blood test. VAD is very rare in developed nations. However, people in impoverished and underdeveloped countries face an uphill struggle with VAD.
Causes
First, let’s understand how much Vitamin A per day should be taken. It is recommended that a minimum of 900 mcg RAE and 700 mcg RAE for men and women, respectively, be consumed daily. When this requirement is not met for a long time, they begin to show the symptoms of VAD.
The root cause of VAD is malnourishment or poor nutritional intake. VAD can also occur due to secondary causes like malabsorption (Celiac disease, Irritable Bowel Syndrome, Crohn's disease, etc.). When the body cannot absorb Vitamin A from food, this can lead to VAD. People with underlying problems like ulcers, Liver Cirrhosis, Measles, Cystic fibrosis, etc, are also prone to VAD. Premature infants and pregnant women are also vulnerable to VAD.
Symptoms
Since Vitamin A is fat-soluble, excess retinol is stored in the body’s liver for a long time. Even when the daily requirement of Vitamin A is not consumed, the stored Vitamin A manages to hold down the fort until it is depleted. For this reason, vitamin A deficiency symptoms take a long time to show up.
The first symptom of VAD is Xerophthalmia. It refers to a wide range of ocular problems arising from VAD. The onset of Xerophthalmia is marked by night blindness, or nyctalopia, wherein a person has difficulty seeing in poor or dim light. Soon it may be followed by:
- Conjunctival xerosis occurs when the membrane that protects the eye becomes dry
- Bitot Spots: Keratin builds up in whitish, triangular shapes on the conjunctiva
- Corneal Xerosis, dryness in the cornea
- Corneal ulcers and the formation of open sores on the cornea
- Keratomalacia, corneal melting or softening
- Xerophthalmic fundus, degeneration of the retina
With each stage, the affected people grow increasingly blind.
Other symptoms of VAD that accompany visual impairment are:
- Infections due to a poor immune system
- Dry Skin
- Acne
- Poor wound healing
- Fertility issues
- Stunted or delayed growth among children
Dietary Solutions
Once you start developing Corneal ulcers, it is a sign that VAD has reached the point of no return. It is hard to reverse the damage done to the eyes at this stage. Further aggravation is usually prevented with the help of Vitamin A Supplements (VAS). For milder stages of VAD, smaller doses of VAS and a healthy diet with foods high in Vitamin A can make a lot of difference.
Foods rich in Vitamin A
Liver: Similar to humans, Vitamin A is stored in the livers of animals, making them a rich source of Vitamin A.
Fish: Cod liver oil is a popular source of Vitamin A.
Eggs
Fruits and Vegetables: Preformed Vitamins (carotenoids) are found in large amounts in fruits and vegetables with green, orange, red, or yellow colors. This includes carrots, pumpkins, apricots, broccoli, spinach, cantaloupe, red peppers, sweet potatoes, mangoes, papaya, etc. Vitamin A fruits and vegetables are the best sources for vegans.
Dairy products: Like milk, yogurt, cheese, and butter are also major Vitamin A food sources.
Conclusion
Like most Vitamins, Vitamin A is also crucial for protecting and maintaining the overall health of our body. A person who has recently contracted or recovered from an infection is more likely to develop VAD. Soon, with a weakened immune system, they are at risk of being infected with more diseases, perpetuating a vicious cycle that is hard to break.
This can be prevented by incorporating foods rich in Vitamin A into our daily diet. In cases of lack of bioavailability of such foods in certain places, they can be replaced by fortified foods or VAS. However, one has to be careful not to overdo it. Although our body naturally stops absorbing retinol from the gut after it reaches an upper limit, consuming too much Vitamin A can also cause toxicity.