Vitamin A

Vitamin A is a fat-soluble vitamin crucial for vision, immune function, reproduction, and cell health. Found as retinol in animal products and beta-carotene in plants, it supports healthy eyesight and skin. Balanced intake is essential, as both deficiency and excess can harm health.

Adequate intake is crucial for overall health, as a deficiency can lead to vision problems and a weakened immune system. Incorporating vitamin A-rich foods like carrots, sweet potatoes, and dairy into your diet is important for maintaining optimal health.

Table of Contents

What’s vitamin A?

The fat-soluble molecules that make up vitamin A, such as retinol, retinal, and retinyl esters, are sometimes mistaken for a single nutrient.
Two kinds of vitamin A can be found in food.
Fish, dairy, and liver are incomparable foods that contain preformed vitamin A( retinol and retinyl esters), although fruits, vegetables, and oils are heavy sources of provitamin A carotenoids.
Your body must generate the active forms of vitamin A, retinoic acid, and retinal before you can use either type.
Because it dissolves in fat, vitamin A is stored in bodily tissue for future use.
Your liver stores the majority of vitamin A in your body as retinyl esters.
After being broken down, these esters form all trans- retinol, which attaches itself to retinol-binding protein. After that, it gets into your bloodstream, where your body may use it.

Functions of Vitamin A in your body

Vitamin A is vital to your well-being. It aids in fetal development, immunological response, cell proliferation, and eyesight.
Vitamin A’s importance in eyesight and eye health is arguably one of its best-known uses.
The chemical required for color and low light vision, rhodopsin, is created when the protein opsin and the active form of vitamin A, the retina, interact.
The conjunctiva, a thin membrane that covers the surface of your eye and the inside of your eyelids, and the cornea are likewise preserved and protected by it. is the furthest position of your eye.
Furthermore, your skin, intestines, lungs, bladder, and inner ear are among the surface tissues that vitamin A promotes.
It helps your body fight against infections by promoting the development and proliferation of T cells, which are white blood cells.
moreover, vitamin A promotes the health of skin cells, fetal growth, and male and female reproductive health.

Health benefits

An essential nutrient with numerous health advantages is vitamin A.

Potent Antioxidant
It may protect against certain cancers
Vital for fertility and fetal development
Boosts your immune system

Potent antioxidant:

People in this group are less likely to get heart disease, lung cancer, and diabetes, among other illnesses.
Alpha-carotene, beta-carotene, beta-cryptoxanthin, and other provitamin A carotenoids are precursors of vitamin A and possess antioxidant qualities.
Carotenoids shield the body from free radicals, which are very reactive chemicals that can cause oxidative stress and damage to the body.
Chronic conditions including diabetes, cancer, heart complaint, and cognitive degeneration have all been related to oxidative stress
Vitamin A is crucial for eyesight and eye health, as was previously established.
Consuming enough vitamin A through food helps prevent age-related macular degeneration( AMD) and other eye conditions.
Carotenoid nutrients protect retinal tissue by reducing oxidative stress, which is connected to this risk decrease.

It may protect against certain cancers:

Vegetables and fruits high in carotenoid content may offer some cancer prevention due to their antioxidant qualities.
Alpha-carotene and beta-cryptoxanthin levels in smokers were shown to be 46 and 61 lower, respectively, than in nonsmokers with the lowest consumption of these nutrients in research including over 10,000 participants.
Furthermore, research conducted in test tubes shows that retinoids may prevent the development of several cancer cells, including those found in the breast, ovary, and bladder.

Vital for fertility and fetal development:

Due to its involvement in the creation of sperm and eggs, vitamin A is necessary for both male and female reproduction.
moreover, it’s essential for fetal growth, placental fitness, and the creation and preservation of fetal tissue.
Thus, vitamin A is essential for the health of those who are attempting to conceive as well as pregnant women and their growing unborn children.

Boosts your immune system:

Vitamin A affects immune function by inducing defense mechanisms that shield your body from infections and diseases.
Some cells, such as B cells and T cells, which are essential for immunological responses that prevent illness, are made using vitamin A.
Lack of this vitamin causes pro-inflammatory molecules to rise, which impairs immune system function and reaction.

Deficiency Of Vitamin A

Although vitamin A insufficiency is uncommon in industrialized nations like the US, it’s prevalent in underdeveloped nations where people may not have easy access to foods high in provitamin A carotenoids and preformed vitamin A.
Vitamin A insufficiency is the primary avoidable cause of blindness in children globally, according to the World Health Organisation.
Additionally, a lack of vitamin A makes diseases like diarrhea and measles more severe and raises the chance of death.
Additionally, studies have shown that vitamin A deficiency harms the fetus by decreasing growth and development and increases the risk of anemia and mortality in pregnant mothers.
Skin conditions including hyperkeratosis and acne are less severe signs of vitamin A insufficiency.
Vitamin A insufficiency is more likely to affect some populations than others, including preterm babies, those with cystic fibrosis, and pregnant or nursing women in impoverished nations.

Food sources Of Vitamin A

Preformed vitamin A and provitamin A carotenoids are found in a wide variety of foods.

Plant-based provitamin A carotenoids are more difficult for your body to absorb and utilize than preformed vitamin A.

Genetics, nutrition, general health, and medicines are some of the numerous variables that affect how well your body converts carotenoids, such as carotene, into active vitamin A.

Vegans and other plant-based diet adherents should thus be careful to get adequate foods high in carotenoid content.

The following foods are the richest in preformed vitamin A:

egg yolks
beef liver
liverwurst
butter
cod liver oil
chicken liver
salmon
cheddar cheese
liver sausage
king mackerel
trout

Beta-carotene and other provitamin A carotenoids are found in the following foods.

sweet potatoes
pumpkin
carrots
kale
spinach
dandelion greens
collard greens
winter squash
cantaloupe
papaya
red peppers

Toxicity and dosage recommendations

Vitamin A excess can be hazardous, just as a lack can have detrimental effects on health.

The daily recommended dietary allowance (RDA) for vitamin A is 700 mcg for women and 900 mcg for males. You may easily meet this consumption amount if you eat a lot of whole foods.

The Tolerable Upper Intake Level (UL) for adults must be kept below 10,000 IU (3,000 mcg) per day in order to prevent toxicity.

Overconsumption of preformed vitamin A can occur from animal-based sources such as the liver, although toxicity is typically associated with excessive supplementation and the use of specific drugs, such as isotretinoin.

The following are the most typical adverse symptoms of chronic vitamin A poisoning, also known as hypervitaminosis A:

vision disturbances
bone pain
joint pain
poor appetite
nausea and vomiting
sunlight sensitivity
hair loss
dry skin
liver damage
jaundice
delayed growth
decreased appetite
confusion
itchy skin

Which vegetables have vitamin A?

Plant carotenoids can be converted by your body into vitamin A.

Beta-carotene and alpha-carotene, which together make up provitamin A, are examples of these carotenoids.

Yet, a genetic mutation that drastically lowers a person’s capacity to convert provitamin A into vitamin A is present in roughly 45% of persons.

These veggies may have significantly less vitamin A than recommended, depending on your genetic makeup.

Sweet potato, baked
Butternut squash, baked
Kale, cooked
Collard greens, cooked
Turnip greens, cooked
Carrots, cooked
Sweet red pepper, raw
Swiss chard, cooked
Spinach, cooked
Romaine lettuce, raw

Which fruits have vitamin A?

Mango
Cantaloupe
Grapefruit
Watermelon
Papaya
Apricot
Tangerine
Nectarine
Guava
Passion fruit

Summary

Vitamin A is an essential fat-soluble nutrient for healthy eyes, the immune system, reproduction, and fetal development.

Intake that is either insufficient or excessive can have serious adverse effects. Therefore, it’s important for adults to meet the RDA of 700–900 mcg per day, but it’s also important to stay below the daily upper limit of 3,000 mcg instead.

Giving your body a safe quantity of this vital nutrient can be achieved through a nutritious, well-balanced diet.

FAQ’s

What is vitamin A known for?

Retinol and retinoic acid, sometimes known as vitamin A, are essential nutrients for immunity, development, cell division, eyesight, and reproduction. Additionally, vitamin A has antioxidant qualities.

Which food is rich in vitamin A?

Leafy greens( kale, spinach, broccoli), as easy as orange and yellow veggies( sweet potatoes, pumpkin, carrots, and varied winter and summer squash)
The tomato.
A red bell pepper.
Mango, cantaloupe.
liver of beef.
Fish fats.
Milk.
eggs.

What are the functions of vitamin A?

Vitamin A is a fat-soluble vitamin that naturally occurs in a wide variety of foods. Normal eyesight, the immune system, reproduction, and growth and development all depend on vitamin A. Additionally, vitamin A supports healthy heart, lung, and other organ functions.

Which fruit is very rich in vitamin A?

Beta-carotene is a precursor to vitamin A and an antioxidant that may be found in orange and yellow foods. Mango and cantaloupe are very high in vitamin A. Other fruits, such as grapefruit and papaya, contain some vitamin A, but less than 10% of the daily value per serving.

How do you prevent vitamin A deficiency?

People should consume carrots, yellow vegetables (like squash and pumpkin), orange and yellow fruits (like papayas and oranges), and dark green leafy vegetables to help avoid vitamin A deficiency. Vitamin A-fortified milk and cereals, liver, egg yolks, and fish liver oils are additional dietary sources.

References:

Rupapara, H. (2023, April 10). Vitamin A deficiency – Cause, symptoms, treatment – Samarpan. Samarpan Physiotherapy Clinic. https://samarpanphysioclinic.com/vitamin-a-deficiency/
Rd, J. K. M. (2023, April 24). Vitamin A: benefits, deficiency, toxicity, and more. Healthline. https://www.healthline.com/nutrition/vitamin-a#sources
Vitamin A. (n.d.). Mayo Clinic. https://www.mayoclinic.org/drugs-supplements-vitamin-a/art-20365945
Vitamin A. (2024, November 6). The Nutrition Source. https://nutritionsource.hsph.harvard.edu/vitamin-a/