Explore the ABCs of Vitamin A and its health benefits with Meri Sehat. Make informed choices for a healthier lifestyle.

"The ABCs Of Vitamin A – A Guide For A Healthier You"

For humans, vitamin A is a vital nutrient. A common misconception is that vitamin A is just one nutrient. In reality, vitamin A is a group of fat-soluble compounds that include retinal, retinol, and retinyl esters. These compounds are found in both animal and plant foods.

Introduction

Vitamin A is fat-soluble, i.e., it can be easily stored in body tissue for later use. It supports immunity, cell growth, fetal development, eye health, and vision. Besides, vitamin A is also essential for surface tissues, like the skin, inner ear, lungs, intestines, and bladder.

Too many health benefits make it sound tempting, but it can be harmful, too. Vitamin A in excess can cause adverse health impacts, like severe headaches, muscle aches, and coma6. On the other hand, a deficiency can also cause severe complications, including a risk of dying from infections like <a href="merisehat.pk/disease/measles">measles </a>and diarrhea<a href="#accordion">[5]</a>.

So, what is the adequate amount of vitamin A? Let&rsquo;s find out! 
&nbsp;

Understanding Vitamin A: Your Guide to a Healthier You

There are two different sources of vitamin A: 
&nbsp;

<ol>
	<li>
	<h5>Preformed Vitamin A</h5>
	</li>
</ol>

It is the active form of vitamin A, which your body can use just as it is without changing into another form. It can be found in fish (e.g., salmon, trout, herring, and king mackerel), beef/chicken liver, cod liver oil, dairy items (e.g., milk, butter, and cheese), egg yolks, and fortified breakfast cereals.

Note: Organ meats are also high in cholesterol. Eat responsibly. 
&nbsp;

<ol start="2">
	<li>
	<h5>Provitamin A Carotenoids</h5>
	</li>
</ol>

The main provitamin A carotenoids in your diet include alpha-carotene, beta-carotene, and beta-cryptoxanthin. They are the vitamin&#39;s inactive form, which your body converts to vitamin A in the small intestine.

Provitamin A carotenoids are generally present in plant-based foods, including pumpkin, spinach, sweet potatoes, broccoli, carrots, kale, papaya, apricots, mangoes, and red peppers. They are also present in fortified breakfast cereals.

Other carotenoids in your food, like lutein, lycopene, and zeaxanthin, are called non-provitamin A carotenoids because they are not converted into vitamin A<a href="#accordion">[6]</a>. 
&nbsp;

<ol start="3">
	<li>
	<h5>Supplements</h5>
	</li>
</ol>

Supplements help those who cannot absorb the nutrient due to a genetic mutation, age, or other medical conditions<a href="#accordion">[7]</a>.

It is usually available as retinyl palmitate or retinyl acetate (preformed vitamin A) and beta-carotene (provitamin A). It can also be present as a combination of both provitamin and preformed vitamin A.

Consider taking vitamin A supplements with fat-containing food for maximum absorption because vitamin A is fat-soluble. It is absorbed more quickly and effectively into the bloodstream when consumed with fat. While most animal-sourced food products rich in vitamin A are packed with fat, most plant-based sources of provitamin A are not. 
&nbsp;

Remember! Vitamin A supplements are NOT necessary if you eat a well-balanced diet. 
&nbsp;

<h5>Vitamin A And Medicines</h5>

If you take vitamin A as a supplement (stand-alone or multivitamin), it can interact with other medicines. E.g<a href="#accordion">[6]</a>:

<ul>
	<li>Acitretin (for psoriasis) and bexarotene (to alleviate skin symptoms of T-cell lymphoma) are made from vitamin A. If you take vitamin A supplements along with these medicines, you risk increasing vitamin A levels in your blood to dangerously high levels.</li>
	<li>Orlistat, which is advised for weight loss, decreases the absorption of vitamin A.</li>
</ul>

Note: Always consult a doctor before taking any dietary supplement. Excessive supplement intake is frequently linked to vitamin toxicity. For instance, chronic (i.e., more than the recommended daily intake) or one large dose of over 200 mg of vitamin A can cause hypervitaminosis A. 
&nbsp;

Your age and gender determine the dose of vitamin A you require<a href="#accordion">[6]</a>. 
&nbsp;

The recommended dietary allowance of preformed vitamin A and provitamin A carotenoids is:

<ul>
	<li>Birth-6 Months &ndash; 400 mcg retinol activity equivalents (RAE)</li>
	<li>7-12 Months &ndash; 500 mcg RAE</li>
	<li>1-3 Years &ndash; 300 mcg RAE</li>
	<li>4&ndash;8 Years &ndash; 400 mcg RAE</li>
	<li>9&ndash;13 Years &ndash; 600 mcg RAE</li>
	<li>14-18 (Boys) &ndash; 900 mcg RAE</li>
	<li>14-18 (Girls) &ndash; 700 mcg RAE</li>
	<li>Adult Men &ndash; 900 mcg RAE</li>
	<li>Adult Women &ndash; 700 mcg RAE</li>
	<li>Pregnant Teens &ndash; 750 mcg RAE</li>
	<li>Pregnant Women &ndash; 770 mcg RAE</li>
	<li>Breastfeeding Teens &ndash; 1,200 mcg RAE</li>
	<li>Breastfeeding Adults &ndash; 1,300 mcg RAE 
	&nbsp;</li>
</ul>

The daily upper limits for preformed vitamin A are:

<ul>
	<li>Birth-12 Months &ndash; 600 mcg</li>
	<li>1-3 Years &ndash; 600 mcg</li>
	<li>4-8 Years &ndash; 900 mcg</li>
	<li>9-13 Years &ndash; 1,700 mcg</li>
	<li>14-18 Years &ndash; 2,800 mcg</li>
	<li>19+ &ndash; 3,000 mcg 
	&nbsp;</li>
</ul>

Note: These levels don&rsquo;t apply if your doctor has recommended otherwise. Also, there are no upper limits for beta-carotene and other forms of provitamin A. 
&nbsp;

The most obvious symptom of vitamin A deficiency is an eye condition known as xerophthalmia. Xerophthalmia is the inability to perceive objects in low light, which can cause visual impairment if not treated.

Moreover, long-term vitamin A deficiency may increase the likelihood of respiratory ailments, like pneumonia, and infections, such as measles and diarrhea.

Other symptoms of vitamin A deficiency include:

<ol>
	<li>Skin problems like dry skin, hyperkeratosis, and acne</li>
	<li>Night blindness</li>
	<li>Dry eyes</li>
	<li>Corneal ulcers</li>
	<li>Reduced immunity</li>
	<li>Delayed growth and development</li>
	<li>Impaired taste and smell</li>
	<li>Hair and nail problems</li>
	<li>Infertility and trouble conceiving</li>
	<li>Poor wound healing 
	&nbsp;</li>
</ol>

<ul>
	<li>
	<h5>Skin</h5>
	</li>
</ul>

Vitamin A (retinol) stimulates collagen production and reduces the appearance of wrinkles and fine lines. It also improves skin elasticity by removing damaged elastin fibers and promoting the formation of new blood vessels.

Carotenoids especially prevent cell damage from environmental factors, like UV radiation and pollution. Hence, retinoids are recommended to reduce hyperpigmentation and achieve an even skin tone overall. Moreover, retinoids help treat acne and psoriasis and help reduce inflammation due to the formation of cytokines and interleukins.

It is still being determined whether non-prescription retinol performs as well as prescription products like tretinoin. 
&nbsp;

<ul>
	<li>
	<h5>Immune System</h5>
	</li>
</ul>

Vitamin A is essential for maintaining your immune system. It promotes the growth of certain cells, including B cells and T cells that safeguard us from infectious diseases. 
&nbsp;

<ul>
	<li>
	<h5>Eye</h5>
	</li>
</ul>

Vitamin A is necessary for maintaining your vision as it is the essential component of rhodopsin, the light-sensitive protein in the retina. Sufficient vitamin A intake in the diet protects against specific eye diseases like age-related macular degeneration. 
&nbsp;

<ul>
	<li>
	<h5>Reproductive System</h5>
	</li>
</ul>

Vitamin A is required for both male and female fertility because it aids in the development of sperm and eggs. It is also necessary for placental health, fetal tissue development and maintenance, and fetal growth<a href="#accordion">[3]</a>. 
&nbsp;

<ul>
	<li>
	<h5>Bone</h5>
	</li>
</ul>

A sufficient intake of vitamin A is also needed to promote healthy bone growth and development. 
&nbsp;

<ul>
	<li>
	<h5>Other</h5>
	</li>
</ul>

As an antioxidant, it reduces free radical damage to DNA, which is linked to chronic conditions like cancer, cognitive decline, diabetes, and heart disease. 
&nbsp;

Elevated natural or synthetic vitamin A levels can have various negative consequences. Vitamin A toxicity, also generally regarded as hypervitaminosis A, is more typically attributed to supplement misuse than health intervention programs.

In particular, excessive amounts of preformed vitamin A (generally from supplements or specific medications) can lead to severe headaches, hazy vision, nausea, lightheadedness, muscle pain, and issues with coordination. In serious instances, it can even induce coma and eventually death. 
&nbsp;

Acute vitamin A toxicity can occur after consuming 25,000 IU/kg or more in a single dose<a href="#accordion">[4].</a> The signs and symptoms are given below:

<ul>
	<li>Nausea</li>
	<li>Vomiting</li>
	<li>Diarrhea</li>
	<li>Lightheadedness</li>
	<li>Tiredness</li>
	<li>Lack of energy</li>
	<li>Elevated intracranial pressure</li>
	<li>Skin changes, like erythema, pruritus, or desquamation 
	&nbsp;</li>
</ul>

Chronic vitamin A toxicity can occur after consuming 4000 IU/kg or more daily for 6-15 months.

The signs and symptoms are given below:

<ul>
	<li>Low-grade fever</li>
	<li>Severe headache</li>
	<li>Tiredness</li>
	<li>Anorexia</li>
	<li>Intestinal problems</li>
	<li>Hepatosplenomegaly</li>
	<li>Anemia</li>
	<li>Hypercalcemia</li>
	<li>Subcutaneous inflammation</li>
	<li>Nocturia</li>
	<li>Joint and bone aches</li>
	<li>Skin changes, such as yellowing, dryness, alopecia, and photosensitivity 
	&nbsp;</li>
</ul>

Acute vitamin A toxicity, while less widespread than chronic vitamin A toxicity, is linked to more serious symptoms, such as liver damage and even death. 
&nbsp;

Important!

Since excessive amounts of vitamin A can be injurious, seek medical advice before taking vitamin A supplements. 
&nbsp;

Excessive vitamin A consumption during pregnancy has been associated with congenital anomalies, such as atypical eyes, skull, lungs, and heart.

Vitamin A is not recommended in the following cases:

<ul>
	<li>Pregnancy</li>
	<li>Nursing mothers</li>
	<li>Individuals with hypersensitivity to this class of medicine 
	&nbsp;</li>
</ul>

Additionally, it is recommended with caution in patients who have:

<ul>
	<li>Liver disease</li>
	<li>Kidney disease</li>
	<li>Alcoholism</li>
	<li>Acne vulgaris 
	&nbsp;</li>
</ul>

Note: Always inform your doctor about your medical history and if you&rsquo;re currently taking any medication. They&rsquo;ll recommend a dosage according to your needs. 
&nbsp;

Conclusion

Vitamin A is necessary for many bodily processes like vision, growth, cell division, reproduction, and immune system operation. It can be found in both animal and plant-based food sources. In case you cannot get enough through diet alone, supplements are available. However, consuming too much vitamin A may affect your health negatively.&nbsp; 
&nbsp;

Key Takeaways

<ul>
	<li>While vitamin A toxicity is less prevalent than deficiency, both conditions can have short-term and long-term negative consequences on health.</li>
	<li>Vitamin A has many health benefits. It&rsquo;s good for the skin, eyes, immune system, and reproductive system.&nbsp;</li>
</ul>

[1] Huiming Y, Chaomin W, Meng M. Vitamin A for treating measles in children. Cochrane database Syst Rev. 2005;(4):CD001479--CD001479.

[2] of Medicine I, on Micronutrients P, Board N, on Upper Reference Levels of Nutrients S, of Interpretation, of Dietary Reference Intakes U, et al. Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. Dietary Reference Intakes; 2002.

[3] Bastos Maia S, Rolland Souza AS, Costa Caminha M de F, da Silva S, Callou Cruz R de SBL, dos Santos C, et al. Vitamin A and pregnancy: a narrative review. Nutrients. 2019;11(3):681.

[4] Hathcock JN, Hattan DG, Jenkins MY, McDonald JT, Sundaresan PR, Wilkening VL. Evaluation of vitamin A toxicity. Am J Clin Nutr. 1990;52(2):183–202.

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