Vitamin A Benefits, food sources and toxicity

Whenever Vitamin A benefits are talked about, Eye health comes into our minds. However, Vitamin A is also used to treat skin disorders like acne, hair growth, wound healing and blood cancers like acute promyelocytic leukemia.

[caption id="attachment_10700" align="aligncenter" width="600"]color vision testing Can you read the numbers correctly (7, 13, 16, 8, 12, and 9)[/caption]

What is Vitamin A?

Vitamin A, lipid-soluble vitamin, absorbed in its active form, retinol, from animal sources. Plants also contain vitamin A, the carotene or the provitamin A.

What are the sources Of Vitamin A:

Liver, kidney, egg yolk, and butter are typical food sources of vitamin A. The provitamin A is found in green leafy vegetables, carrots, and sweet potatoes. About 50 to 80% of the total body retinol or vitamin A is stored in the liver.

Food Sources of Vitamin A Retinol activity equivalence % of adult male RDA
cod liver oil 30000 μg 3333%
liver (turkey 8058 μg 895%
liver (beef, pork, fish 6500 μg 722%
liver (chicken) 3296 μg 366%
ghee 3069 μg 344%
sweet potato 961 μg 107%
carrot 835 μg 93%
broccoli leaf 800 μg 89%
butter 684 μg 76%
kale 681 μg 76%
collard greens (frozen then boiled 575 μg 64%
butternut squash 532 μg 67%
dandelion greens 508 μg 56%
spinach 469 μg 52%
pumpkin 426 μg 43%
collard greens 333 μg 37%
cheddar cheese 265 μg 29%
cantaloupe melon 169 μg 19%
bell pepper/capsicum, red 157 μg 17%
egg 140 μg 16%
apricot 96 μg 11%
papaya 55 μg 6%
tomatoes 42 μg 5%
mango 38 μg 4%
pea 38 μg 4%
broccoli florets 31 μg 3%
milk 28 μg 3%
bell pepper/capsicum, green 18 2%
spirulina 3 μg 0.3%

Table: Food Sources of Vitamin A

Diseases associated with Vitamin A deficiency:

The third most prevalent nutritional deficiency in the world is a lack in vitamin A. Blindness can result from a vitamin A deficiency, particularly in developing  nations. Each year, almost 50000 kids lose their vision. With a width of 300, [caption id="attachment 980" align="alignnone"]

essential vitamins for good health Vitamin A deficiency is the leading cause of blindness in children[/caption]

Vitamin A is essential for the eyes:

Vitamin A deficiency causes dryness of the eyes because of defective tear secretion. This is called as xerophthalmia and is manifested by the presence of Bitot’s spots.

The first sign of vitamin A insufficiency is typically dry eyes and an inability to produce tears. Night blindness is a condition when a person can not see in dim light. Night blindness can be caused by disorders of the eye like retinitis pigmentosa, however, Vitamin A deficiency is a treatable and the most common cause of decreased vision at night.

Vitamin A benefits for eyes:

Vitamin A is essential for the eyes and vision. The light-sensing receptors "Rhodopsin" require vitamin A for their maintenance and regeneration.

Xerophthalmia is a condition caused by vitamin A deficiency that is manifested by night blindness, conjunctival and corneal dryness and keratinization. It is an ophthalmologic emergency and needs timely vitamin A replacement before the individual is blind. Both oral and topical Vitamin A is effective for the treatment of dry eyes.

however, the effects of oral vitamin A may last longer than topical ointments. Topical vitamin A has also been shown (in combination with topical tobramycin) to repair the corneal epithelium. [caption id="attachment_10699" align="aligncenter" width="889"]vitamin a benefits for eyes Bitot’s spots and keratinization of the nasal, inferior, and temporal conjunctiva (see arrows)[/caption]

Vitamin A for skin:

Deficiency of vitamin A causes nonspecific skin changes. These may include skin thickening and the destruction of hair follicles.

Vitamin A benefits for Skin:

Vitamin A protects the skin from ultraviolet rays. It helps in the regeneration of the skin cells and improves immunity. Vitamin A and vitamin A derivatives are available in different formulations including capsules, creams, and gels for the treatment of acne. Adapalene is a topical over the counter available gel for the treatment of acne.

It removes wrinkles and is also used as an anti-aging vitamin. It is also used for rough skin and patients with hyperkeratotic skin lesions such as psoriasis. Vitamin A, along with other vitamins, is used to fade dark marks and hyperpigmented areas.

It lightens the skin and protects the skin from infections. Vitamin A (in combination with Vitamin D) is also added to most sunscreens, moisturizers, and lotions for additional benefits such as sunburns and protection from skin cancers.

Topical Vitamin A and D ointments are also used to treat diaper rash and sunburns. Vitamin A in combination with oral vitamin C may benefit individuals with hair thinning, however, it is important to know that excessive intake of vitamin A may cause hair loss.

Vitamin A: Drug Interaction

Risk Factor D (Consider therapy modification)

Bexarotene (Topical)

Bexarotene's harmful or toxic effects could be exacerbated by vitamin A. (Topical).  Treatment: If topical bexarotene is used in conjunction with vitamin A, dosages should be kept to 5,000 units per day.


May lower the level of vitamins in the serum (Fat Soluble). Treatment: Give orally absorbed fat-soluble vitamins at least two hours before or after taking orlistat. When fat-soluble vitamins are delivered parenterally, same precautions are not necessary.

Risk Factor X (Avoid combination)

Retinoic Acid Derivatives

Retinoic Acid Derivatives' harmful or toxic effects may be exacerbated by vitamin A.  Adapalene, Alitretinoin (Topical), Bexarotene (Topical), and Tretinoin are exceptions (Topical).


Medical Uses of Vitamin A (Other Vitamin A benefits) :

  • Vitamin A is used to treat night blindness and eye diseases due to vitamin A deficiency.

    • For adults, three doses of 200000 IU of vitamin A should be given.
    • Children younger than six months should be given 50,000 IU orally and those between 6 months and one year should be given 100,000.
    • Older children and adults should be given 200,000 IU.
    • Three doses of the same doses are given ( the second dose is given the next day while the third dose is given after 2 weeks).
  • Vitamin A benefits children with measles and it reduces the complications and mortality in patients with measles.

  • It is also used in the treatment of a variety of skin disorders like acne, psoriasis and skin cancers. It is available as a topical gel and solution for skin disorders like acne.

  • Vitamin A is also used in the treatment of acute promyelocytic leukemia with excellent results.

    • Vitamin A is used in these patients as induction therapy.
    • It is used in those patients with PML/RARα gene and t(15;17) translocation.

Other Vitamin A benefits:

Vitamin A deficiency is known to affect immunity and its deficiency results in poor wound healing as well as poor bone growth.

What causes vitamin A deficiency:

Vitamin A deficiency occurs in people with malnutrition and reduced intake of Vitamin A. Since it is a fat-soluble vitamin, its deficiency can also be seen in the following disorders associated with fat malabsorption:

  • Cystic fibrosis,

  • Celiac disease,

  • Liver diseases,

  • Inflammatory bowel diseases like Crohn's colitis, and

  • Pancreatic Insufficiency.

How and When to replace Vitamin A:

The WHO recommends the replacement of Vitamin A in countries where it is endemic.

1. People Residing in endemic areas:

Vitamin A supplements should be given to the population residing in endemic areas at four to six months intervals in a dose of 1 mcg or 3.3 IU.

2. Infants who are not breastfed:

Infants less than 6 months of age who are not breastfed should be given 50000 IU orally. Breastfed infants may be given oral vitamin an only if the mother is deficient or has not received any supplements. Infants 6 -12 months of age be given 100000 IU orally Children 12 months of age or more should receive 200000 IU orally.

3. Replacement of Vitamin A in mothers.

Mothers may be given 200000 IU orally within 8 weeks of delivery. Pregnant women should not be given high doses of vitamin A because of the teratogenic effects of vitamin A 'but may receive frequent small doses of 10000 to 25000 IU weekly.

4. Children at high risk:

Children who are at high risk of vitamin A deficiency such as those with measles, diarrhea, respiratory diseases, and malnutrition may be given supplemental doses according to their age groups as mentioned above.

For patients who become symptomatic, the therapeutic dose of vitamin A is given in three doses as mentioned above. Following diagnosis, the first dose is administered immediately, followed by the second dose the following day, and the third dose two weeks later.

Symptoms of vitamin A toxicity:

Most of the patients who develop vitamin A toxicity are those using high doses of vitamin A supplements. High doses of the provitamin A is less likely to cause toxicity. Patients may develop yellowish discoloration of skin due to carotenemia without evidence of vitamin A toxicity.

Acute vitamin A toxicity:

Vitamin A toxicity can be acute when very high doses of vitamin a is ingested ( >660000 IU). Symptoms of acute toxicity include

Chronic Vitamin A toxicity:

Chronic vitamin A toxicity include

  • Skeletal pains and bone fractures,
  • Hair loss,
  • Liver toxicity even cirrhosis,
  • Headache due to raised intracranial pressure and
  • Abnormal lipid profile.

Other important adverse effects of vitamin a include teratogenic effects, especially when taken in the first trimester. This may lead to abortions and fetal malformations like microcephaly, and cardiac anomalies.

Should you check your blood levels of Vitamin A?


Serum vitamin A levels may be misleading since most of it is stored in the liver and kidneys.

Daily requirements of Vitamin A:

RDA Recommended daily allowance of vitamin A for adult males is 3000 IU and 2300 IU for females.

Vitamins A in Pakistan:

Vitamin A is available as drops, ointments, tablets, capsules, dragees, and injections. It is usually available in combination with other vitamins.


NO Comments Found