What does vitamin a mean?

Definitions for vitamin a
vi·ta·min a

This dictionary definitions page includes all the possible meanings, example usage and translations of the word vitamin a.

Princeton's WordNet

  1. vitamin A, antiophthalmic factor, axerophthol, Anoun

    any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes

Wiktionary

  1. vitamin Anoun

    Any of several closely related fat-soluble vitamins that are essential for normal vision; retinol.

Wikipedia

  1. Vitamin A

    Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin A carotenoids (most notably beta-carotene [β-carotene]). Vitamin A has multiple functions: it is essential for embryo development and growth, for maintenance of the immune system, and for vision, where it combines with the protein opsin to form rhodopsin – the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision.Vitamin A occurs as two principal forms in foods: A) retinol, found in animal-sourced foods, either as retinol or bound to a fatty acid to become a retinyl ester, and B) the carotenoids alpha-carotene, β-carotene, gamma-carotene, and the xanthophyll beta-cryptoxanthin (all of which contain β-ionone rings) that function as provitamin A in herbivore and omnivore animals which possess the enzymes that cleave and convert provitamin carotenoids to retinal and then to retinol. Some carnivore species lack this enzyme. The other carotenoids have no vitamin activity.Dietary retinol is absorbed from the digestive tract via passive diffusion. Unlike retinol, β-carotene is taken up by enterocytes by the membrane transporter protein scavenger receptor B1 (SCARB1), which is upregulated in times of vitamin A deficiency. Storage of retinol is in lipid droplets in the liver. A high capacity for long-term storage of retinol means that well-nourished humans can go months on a vitamin A- and β-carotene-deficient diet, while maintaining blood levels in the normal range. Only when the liver stores are nearly depleted will signs and symptoms of deficiency show. Retinol is reversibly converted to retinal, then irreversibly to retinoic acid, which activates hundreds of genes.Vitamin A deficiency is common in developing countries, especially in Sub-Saharan Africa and Southeast Asia. Deficiency can occur at any age but is most common in pre-school-age children and pregnant women, the latter due to a need to transfer retinol to the fetus. Vitamin A deficiency is estimated to affect approximately one-third of children under the age of five around the world, resulting in hundreds of thousands of cases of blindness and deaths from childhood diseases because of immune system failure. Reversible night blindness is an early indicator of low vitamin A status. Plasma retinol is used as a biomarker to confirm vitamin A deficiency. Breast milk retinol can indicate a deficiency in nursing mothers. Neither of these measures indicates the status of liver reserves.The European Union and various countries have set recommendations for dietary intake, and upper limits for safe intake. Vitamin A toxicity also referred to as hypervitaminosis A, occurs when there is too much vitamin A accumulating in the body. Symptoms may include nervous system effects, liver abnormalities, fatigue, muscle weakness, bone and skin changes, and others. The adverse effects of both acute and chronic toxicity are reversed after consumption of high dose supplements is stopped.

ChatGPT

  1. vitamin A

    Vitamin A is a group of fat-soluble retinoids, including retinol, retinal, retinoic acid, and several provitamin A carotenoids. It is essential for many bodily functions, including maintaining healthy vision, supporting the immune system, and promoting cell growth and development. It can be obtained from various food sources like carrots, spinach, and sweet potatoes, or in supplement form. Deficiency in vitamin A can lead to several health problems, including night blindness and skin issues.

Wikidata

  1. Vitamin A

    Vitamin A is a group of nutritionally unsaturated hydrocarbons, which include retinol, retinal, retinoic acid, and several provitamin A carotenoids, among which beta-carotene is the most important. Vitamin A has multiple functions, it is important for growth and development, for the maintenance of the immune system and good vision. Vitamin A is needed by the retina of the eye in the form of retinal, which combines with protein opsin to form rhodopsin the light-absorbing molecule, that is necessary for both low-light and color vision. Vitamin A also functions in a very different role as an irreversibly oxidized form of retinol known as retinoic acid, which is an important hormone-like growth factor for epithelial and other cells. In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to retinol in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal. The associated acid, a metabolite that can be irreversibly synthesized from vitamin A, has only partial vitamin A activity, and does not function in the retina for the visual cycle. Retinoic acid is used for growth and cellular differentiation.

U.S. National Library of Medicine

  1. Vitamin A

    Retinol and derivatives of retinol that play an essential role in metabolic functioning of the retina, the growth of and differentiation of epithelial tissue, the growth of bone, reproduction, and the immune response. Dietary vitamin A is derived from a variety of CAROTENOIDS found in plants. It is enriched in the liver, egg yolks, and the fat component of dairy products.

Matched Categories

How to pronounce vitamin a?

How to say vitamin a in sign language?

Numerology

  1. Chaldean Numerology

    The numerical value of vitamin a in Chaldean Numerology is: 5

  2. Pythagorean Numerology

    The numerical value of vitamin a in Pythagorean Numerology is: 8

Examples of vitamin a in a Sentence

  1. Keith West:

    In countries where the food system is less sophisticated and we see crushing poverty, the margin between harvest season and hungry season is palpable, these populations can dip into actual deficiency with Vitamin A, especially in respect to young, growing children who can become what we call ‘night blind.'.

  2. Alyssa Burnison:

    Beets contain the antioxidant betalains, which give red beetroots their natural, vibrant red color. Beetroots are also a great source of vitamin C, vitamin A, vitamin K, calcium and iron.

  3. Jim White:

    Beta-carotene has been proven to improve a person’s skin and decrease wrinkles, it’s also converted to vitamin A in the body. Vitamin A is essential for healthy vision. 1 cup of pumpkin contains 200 percent more vitamin A than the RDI (recommended dietary intake).

  4. Rita Linkner:

    Oral vitamin A basically shuts down your sebaceous glands. If you suppress [them] for a long enough period, you can cure someone of their acne, and about 50 percent do hit that cure rate.

  5. Alyssa Burnison:

    Carrots are commonly known for their rich sources of vitamin A and carotenoids, specifically beta-carotene, your body converts the beta-carotene to vitamin A, which has been known to support immune function and eye health.


Translations for vitamin a

From our Multilingual Translation Dictionary

Get even more translations for vitamin a »

Translation

Find a translation for the vitamin a definition in other languages:

Select another language:

  • - Select -
  • 简体中文 (Chinese - Simplified)
  • 繁體中文 (Chinese - Traditional)
  • Español (Spanish)
  • Esperanto (Esperanto)
  • 日本語 (Japanese)
  • Português (Portuguese)
  • Deutsch (German)
  • العربية (Arabic)
  • Français (French)
  • Русский (Russian)
  • ಕನ್ನಡ (Kannada)
  • 한국어 (Korean)
  • עברית (Hebrew)
  • Gaeilge (Irish)
  • Українська (Ukrainian)
  • اردو (Urdu)
  • Magyar (Hungarian)
  • मानक हिन्दी (Hindi)
  • Indonesia (Indonesian)
  • Italiano (Italian)
  • தமிழ் (Tamil)
  • Türkçe (Turkish)
  • తెలుగు (Telugu)
  • ภาษาไทย (Thai)
  • Tiếng Việt (Vietnamese)
  • Čeština (Czech)
  • Polski (Polish)
  • Bahasa Indonesia (Indonesian)
  • Românește (Romanian)
  • Nederlands (Dutch)
  • Ελληνικά (Greek)
  • Latinum (Latin)
  • Svenska (Swedish)
  • Dansk (Danish)
  • Suomi (Finnish)
  • فارسی (Persian)
  • ייִדיש (Yiddish)
  • հայերեն (Armenian)
  • Norsk (Norwegian)
  • English (English)

Word of the Day

Would you like us to send you a FREE new word definition delivered to your inbox daily?

Please enter your email address:


Citation

Use the citation below to add this definition to your bibliography:

Style:MLAChicagoAPA

"vitamin a." Definitions.net. STANDS4 LLC, 2024. Web. 29 Mar. 2024. <https://www.definitions.net/definition/vitamin+a>.

Discuss these vitamin a definitions with the community:

0 Comments

    Are we missing a good definition for vitamin a? Don't keep it to yourself...

    Image or illustration of

    vitamin a

    Credit »

    Free, no signup required:

    Add to Chrome

    Get instant definitions for any word that hits you anywhere on the web!

    Free, no signup required:

    Add to Firefox

    Get instant definitions for any word that hits you anywhere on the web!

    Browse Definitions.net

    Quiz

    Are you a words master?

    »
    malicious satisfaction
    A gloat
    B aberrate
    C caddie
    D suffuse

    Nearby & related entries:

    Alternative searches for vitamin a: