Vita A

Vita A Uses, Dosage, Side Effects, Food Interaction and all others data.

Vita A plays an essential role in the function of retina and is essential for growh and differentiation of epithelial tissue.

Vita A is effective for the treatment of Vita A deficiency. Vita A refers to a group of fat-soluble substances that are structurally related to and possess the biological activity of the parent substance of the group called all-trans retinol or retinol. Vita A plays vital roles in vision, epithelial differentiation, growth, reproduction, pattern formation during embryogenesis, bone development, hematopoiesis and brain development. It is also important for the maintenance of the proper functioning of the immune system.

Trade Name Vita A
Generic Vitamin A
Vitamin A Other Names all-trans-retinol, all-trans-retinyl alcohol, all-trans-vitamin A alcohol, Retinol, Retinolum, Vitamin A1
Type
Formula C20H30O
Weight Average: 286.4516
Monoisotopic: 286.229665582
Protein binding

<5% of circulating vitamin A is bound to lipoproteins in blood in normal condition, but may be up to 65% when hepatic stores are saturated because of excessive intake. When released from liver, vitamin A is bound to retinol-binding protein (RBP). Most vitamin A circulates in the form of retinol bound to RBP.

Groups Approved, Nutraceutical, Vet approved
Therapeutic Class Vitamin-A preparations
Manufacturer
Available Country Taiwan
Last Updated: September 19, 2023 at 7:00 am
Vita A
Vita A

Uses

Effective for:

  • Vita A deficiency. Taking vitamin A by mouth is effective for preventing and treating symptoms of vitamin A deficiency. Vita A deficiency can occur in people with protein deficiency, diabetes, over-active thyroid, fever, liver disease, cystic fibrosis, or an inherited disorder called abetalipoproteinemia.

Possibly Effective for:

  • Breast cancer. Premenopausal women with a family history of breast cancer who consume high levels of vitamin A in their diet seem to have reduced risk of developing breast cancer. It is not known if taking vitamin A supplements has the same benefit.
  • Cataracts. Research suggests that high intake of vitamin A in the diet is linked to a lower risk of developing cataracts.
  • Diarrhea related to HIV. Taking vitamin A along with conventional medicines seems to decrease the risk of death from diarrhea in HIV-positive children with vitamin A deficiency.
  • Malaria. Taking vitamin A by mouth seems to decrease malaria symptoms in children less than 3 years-old living in areas where malaria is common.
  • Measles. Taking vitamin A by mouth seems to reduce the risk of measles complications or death in children with measles and vitamin A deficiency.
  • Precancerous lesions in the mouth (oral leukoplakia). Research suggests that taking vitamin A can help treat precancerous lesions in the mouth.
  • Recovery from laser eye surgery (photoreactive keratectomy). Taking vitamin A by mouth along with vitamin E seems to improve healing after laser eye surgery.
  • Complications after pregnancy. Taking vitamin A seems to reduce the risk of diarrhea and fever after pregnancy in malnourished women.
  • Complications during pregnancy. Taking vitamin A by mouth seems to reduce the risk of death and night blindness during pregnancy in malnourished women.
  • Eye disease affecting the retina (retinitis pigmentosa). Research suggests that taking vitamin A can slow the progression of an eye disease that causes damage to the retina.

Vita A is also used to associated treatment for these conditions: Deficiency, Vitamin A, Deficiency, Vitamin D, Degenerative Retinal Disorders, Disorder of the Epithelium, Disorder of the Mesoderm, Inner ear disorder, Vitamin Deficiency, Vitamin E Deficiency, Nutritional supplementation

How Vita A works

Vision:Vita A (all-trans retinol) is converted in the retina to the 11-cis-isomer of retinaldehyde or 11-cis-retinal. 11-cis-retinal functions in the retina in the transduction of light into the neural signals necessary for vision. 11-cis-retinal, while attached to opsin in rhodopsin is isomerized to all-trans-retinal by light. This is the event that triggers the nerve impulse to the brain which allows for the perception of light. All-trans-retinal is then released from opsin and reduced to all-trans-retinol. All-trans-retinol is isomerized to 11-cis-retinol in the dark, and then oxidized to 11-cis-retinal. 11-cis-retinal recombines with opsin to re-form rhodopsin. Night blindness or defective vision at low illumination results from a failure to re-synthesize 11-cis retinal rapidly.
Epithelial differentiation: The role of Vita A in epithelial differentiation, as well as in other physiological processes, involves the binding of Vita A to two families of nuclear retinoid receptors (retinoic acid receptors, RARs; and retinoid-X receptors, RXRs). These receptors function as ligand-activated transcription factors that modulate gene transcription. When there is not enough Vita A to bind these receptors, natural cell differentiation and growth are interrupted.

Dosage

Vita A dosage

Vita A deficiency For severe deficiency with corneal changes: 500,000 unit/day for 3 days, followed by 50,000 unit/day for 2 wk and then 10,000-20,000 unit/day for 2 mth as follow-up therapy.

For cases without corneal changes: 10,000-25,000 unit/day until clinical improvement occurs (usually 1 -2 wk).

Side Effects

Hypervitaminosis A characterised by fatigue, irritability, anorexia, weight loss, vomiting and other Gl disturbances, low-grade fever, hepatosplenomegaly, skin changes, alopoecia, dry hair, cracking and bleeding lips, SC swelling, nocturia, pains in bones and joints.

Toxicity

Acute toxicity to vitamin A can occur when adults or children ingest >100x or >20x the RDA, respectively, over a period of hours or a few days. The RDA for vitamin A differs depending on age and sex and can range from 300 - 900 μg retinol activity equivalents (RAE) per day. Symptoms of acute systemic toxicity generally include mucocutaneous involvement (e.g. xerosis, cheilitis, skin peeling) and may involve mental status changes. Children are typically more susceptible to acute vitamin A toxicity - daily intakes of as little as 1500 IU/kg have been observed to result in toxicity.

Chronic vitamin A toxicity can develop following the long-term ingestion of high vitamin A doses. While there is a wide variation in the lowest toxic vitamin A dose, the ingestion of >25 000 IU daily for 6 years or 100,000 IU daily for 6 months is considered to be toxic. Chronic vitamin A toxicity can affect many organ systems and can lead to the development of osteoporosis and CNS effects (e.g. headaches).

Precaution

Cholestatic jaundice; fat-malabsorption conditions. Monitor patients closely for toxicity. Liver impairment and children.

Interaction

Decreased absorption with neomycin. Increased risk of hypervitaminosis A with synthetic retinoids eg, acitretin, isotretinoin and tretinoin. Increased risk of toxicity when used with alcohol.

Food Interaction

No interactions found.

Elimination Route

Readily absorbed from the normal gastrointestinal tract

Half Life

1.9 hours

Pregnancy & Breastfeeding use

Pregnancy Category A. Adequate and well-controlled human studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).

Contraindication

Hypervitaminosis A; pregnancy (dose exceeding RDA).

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You find simplified version here Vita A

FAQ

What is Vita A?

bran is a fat-soluble vitamin that is naturally present in many foods.It is important for normal vision, the immune system, and reproduction.It also helps the heart, lungs, kidneys, and other organs work properly.

What are the benefits of taking Vita A?

Vita A is an essential vitamin that the body needs for growth and development. It is also vital for cell recognition, vision, immune function, and reproduction.

What are the Vita A foods?

Good sources of Vita A include:

  • cheese
  • eggs
  • oily fish
  • fortified low-fat spreads
  • milk and yoghurt
  • liver and liver products such as liver pâté,this is a particularly rich source of vitamin A, so you may be at risk of having too much vitamin A if you have it more than once a week (if you're pregnant you should avoid eating liver or liver products)
  • You can also get vitamin A by including good sources of beta-carotene in your diet, as the body can convert this into retinol.

  • The main food sources of beta-carotene are:

  • yellow, red and green (leafy) vegetables, such as spinach, carrots, sweet potatoes and red peppers
  • yellow fruit, such as mango, papaya and apricots

Is it safe to take Vita A everyday?

Vita A is likely safe for most people in amounts less than 10,000 units daily. The maximum daily dose of 10,000 units per day relates to only pre-formed Vita A.

What are the common side effects of Vita A?

Long-term use of large amounts of Vita A might cause serious side effects including fatigue, irritability, mental changes, anorexia, stomach discomfort, nausea, vomiting, mild fever, excessive sweating, and many other side effects.

What should you not take Vita A with?

Avoid taking Vita A at the same time as you take neomycin, orlistat, and mineral oil.

Can I take Vita A during pregnancy?

During pregnancy, it's important not to get too much preformed Vita A.Having large amounts of Vita A can harm your unborn baby.

Can I take Vita A during breastfeeding?

Fat soluble vitamins like Vita A can concentrate in breast milk, and excessive amounts of Vita A can be harmful to a baby. In other words, don’t take extra amounts of vitamin A unless your doctor determines you have a serious deficiency and directs you to do otherwise.

Can I dink alcohol with Vita A?

Important not to exceed recommended doses of these vitamins as high supplemental doses may lead to liver damage. Alcohol combined with high doses of these vitamins may theoretically lead to or worsen liver damage.

Can I take Vita A when trying to conceive?

You should limit the amount of  that you take while pregnant or trying to conceive. It is present in many multivitamins and fish liver oil supplements.

How long can I take vitamin A for?

Vita A is possibly when used on the skin, short-term. Retinol 0.5% serum has been used daily for up to 12 weeks without serious side effects.

What are the benefits of taking Vita A?

Vita A is an essential vitamin that the body needs for growth and development. It is also vital for cell recognition, vision, immune function, and reproduction.

What are the symptoms of low Vita A?

  • Night blindness.
  • Xerophthalmia.
  • Infection.
  • Bitot spots.
  • Skin irritation.
  • Keratomalacia.
  • ‌Keratinisation.
  •  Stunted growth.

How long does it take to correct a Vita A deficiency?

It's going to take between 6 weeks and 3 months to correct most nutritional deficiencies.

How much Vita A should a woman take daily?

The recommended daily amount of vitamin A is 900 micrograms (mcg) for adult men and 700 mcg for adult women.

Can too much Vita A cause hair loss?

Consuming too much Vita A over a long period of time can cause coarse hair.

Which disease is caused by lack of Vita A?

Night blindness is one of the first signs of Vita A deficiency.In its more severe forms, Vita A deficiency contributes to blindness by making the cornea very dry, thus damaging the retina and cornea.

How can I increase my Vita A?

The top food sources of Vita A include dairy products, liver, fish, and fortified cereals. The top sources of Vita A include carrots, broccoli, cantaloupe, and squash.

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*** Taking medicines without doctor's advice can cause long-term problems.
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