vitamin A

n. Any of various related fat-soluble compounds, especially vitamin A₁ (retinol), obtained principally from milk, eggs, and liver or produced in the body from beta carotene in plant foods, and functioning in cell growth and differentiation, the visual system, and the immune system. Vitamin A deficiency can cause blindness and damage to epithelial tissues.

vitamin A₁

n. A yellow crystalline compound, C₂₀H₃₀O, that is the principal form of vitamin A found in most vertebrates other than freshwater fish. Also called retinol.

vitamin A₂

n. A fat-soluble vitamin, C₂₀H₂₈O, occurring chiefly in freshwater fish and other freshwater vertebrates, where it is a component (in aldehyde form) of the retinal pigment porphyropsin.

vitamin A

n (Elements & Compounds) a fat-soluble yellow unsaturated alcohol occurring in green and yellow vegetables (esp carrots), butter, egg yolk, and fish-liver oil (esp halibut oil). It is essential for the prevention of night blindness and the protection of epithelial tissue. Formula: C20H30O. Also called: vitamin A1 or retinol

vitamin A

n. a yellow, fat-soluble terpene alcohol, C₂₀H₃₀O, obtained from carotene and occurring in green and yellow vegetables, egg yolk, etc.: essential to the protection of epithelial tissue and the prevention of night blindness. Also called vitamin A₁, retinol. [1920–25]

vitamin A2

n. a yellow oil, C₂₀H₂₈O, similar to vitamin A, obtained from fish liver.

vitamin A

A vitamin important for normal vision, tissue growth, and healthy skin. It is found in fish-liver oils, milk, green leafy vegetables, and yellow vegetables and fruits. Also called retinol.

Thesaurus

Noun

vitamin A - any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyesantiophthalmic factor, axerophthol, Afat-soluble vitamin - any vitamin that is soluble in fatsretinol, vitamin A1 - an unsaturated alcohol that occurs in marine fish-liver oils and is synthesized biologically from carotenedehydroretinol, vitamin A2 - a viscous alcohol that is less active in mammals than is vitamin A1

vitamin A

vi·ta·min A

1. any β-ionone derivative, except provitamin A carotenoids, possessing qualitatively the biologic activity of retinol; deficiency interferes with the production and resynthesis of rhodopsin, thereby causing night blindness, and produces a keratinizing metaplasia of epithelial cells that may result in xerophthalmia, keratosis, susceptibility to infections, and retarded growth; 2. the original vitamin A, now known as retinol. Synonym(s): axerophthol

vitamin A

n. A fat-soluble vitamin or a mixture of vitamins, especially vitamin A₁ or a mixture of vitamins A₁ and A₂, occurring principally in fish-liver oils, milk, and some yellow and dark green vegetables, and functioning in normal cell growth and development. Vitamin A deficiency can cause damage to epithelial cells, resulting in hardening and roughening of the skin, degeneration of mucous membranes, and night blindness. Also called retinol.

vitamin A₁

n. A yellow crystalline compound, C₂₀H₃₀O, extracted from egg yolks, milk, and cod-liver oil.

vitamin A₂

n. A golden yellow oil, C₂₀H₂₈O, occurring chiefly in the livers of freshwater fish and having about 40 percent of the biological activity of vitamin A₁.

vi·ta·min A

(vīt'ă-min) 1. Any β-ionone derivative, except provitamin A carotenoids, possessing qualitatively the biologic activity of retinol; deficiency interferes with the production and resynthesis of rhodopsin, thereby causing night blindness, and produces a keratinizing metaplasia of epithelial cells that may result in xerophthalmia, keratosis, susceptibility to infections, and retarded growth. 2. The original vitamin A, now known as retinol.

vitamin A

retinol

a fat-soluble hydrocarbon, closely related to CAROTENOIDS, that occurs in liver, green vegetables and storage organs such as carrots. It can be produced in the body from the pigment 3-carotene. It is concerned with the normal functioning of the mucous membrane of the eye, respiratory and urinogenital tracts, and forms part of the photochemical reactions in the RODS of the eye. Deficiency of vitamin A leads firstly to night blindness then xerophthalmia, inflamed eyes and eyelids and eventual blindness. The lining of the respiratory tract can become inflamed. Infants obtain a large supply of the vitamin in the mother's first milk (COLOSTRUM).

vi·ta·min A

(vīt'ă-min) 1. Any β-ionone derivative, except provitamin A carotenoids, possessing qualitatively the biologic activity of retinol; deficiency interferes with production and resynthesis of rhodopsin, thereby causing night blindness. 2. Retinol, original vitamin A.

Patient discussion about vitamin A

Q. Can a food rich in vitamin B12 will help for his depression or vitamin B12 pills are always required? Hi all…..having one question related to my friends depression and its relation to vitamin B12, as a medicine given to him by his Doctor. Can a food rich in vitamin B12 will help for his depression or vitamin B12 pills are always required?A. Yes low level of vitamin B12 is associated with depression. You can complete its deficiency by having good diet which will cover the B12 requirements. What happens that depressed people tend to eat less of healthy food and which reduces the B12. So, it again reduces the capacity to fight against the depression.

Q. Can someone give me some information on over intake of Vitamin A and its complications in future? I am having short sightedness. I am wearing specks for the past 3 years. Last week my eye sight had doubled. I never thought to control my eye sight by having a good diet, which is rich in vitamin A. Now I am willing to have vitamin A in tablets and I doubt the adverse effects if taken in excess. Can someone give me some information on over intake of Vitamin A and its complications in future?A. Having tablets will fortify you with vitamin A but long term intake will lead to show the side effects of over intake. You can have these vitamin tablets as per your doctor’s prescription. But you must have them as a diet intake which will keep your vitamin intake balanced and will not lead to any complications. But the over intake of vitamins can lead to vitamin A toxicity. This can show symptoms as fatigue, muscle pain, depression, Fever and liver anemia.
http://www.youtube.com/watch?v=EOVwmGvQI5k&eurl=http://www.imedix.com/health_community/vEOVwmGvQI5k_eye?q=short%20eye%20sight&feature=player_embedded

Q. What is a normal Vitamin D level in an 84 year old woman? How would one correct a level of 50 in a Vitamin D level test?A.

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vitamin A₁

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vi·ta·min A

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vitamin A₂

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retinol

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Patient discussion about vitamin A

vitamin A

Synonyms for vitamin A

noun any of several fat-soluble vitamins essential for normal vision

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