II. Physiology: Function

  1. General
    1. Vitamin A (Retinol) is derived from ingested retinyl esters or pro-CarotenoidProteins (beta-carotene, alpha-carotene, and beta-cryptoxanthin)
    2. Most of Vitamin A (90%) is stored in the liver as retinyl esters and released as needed
  2. Vision
    1. Cis-Retinal is sythesized from Vitamin A (Retinol)
    2. Cis-Retinal combines with an opsin Protein to form Retinal photoreceptor pigments (rhodopsin in rods, iodopsin in cones)
  3. Epithelial Cell function (skin, mucosa)
    1. Helps maintain skin and mucosa integrity and innate imunity
    2. Roche (2021) Nutrients 13(2):302 +PMID: 33494277 [PubMed]
  4. Bone growth
    1. Promotes Osteoblast activity and inhibits Osteoclast activity
    2. Yee (2021) Molecules 26(6):1757 +PMID: 33801011 [PubMed]
  5. Glycoprotein synthesis
    1. Vitamin A appears to be a Cofactor in Glycoprotein synthesis

III. Pathophysiology

  1. Vitamin A Deficiency
    1. Night blindness
    2. Dry Cornea
    3. Dry Skin
  2. Vitamin A Toxicity or Overdose
    1. Vomiting
    2. Headache
    3. Altered Mental Status
    4. Alopecia
    5. Peeling skin

IV. Preparations: Sources

  1. Animal products
    1. Liver (beef liver, cod liver oil)
    2. Chicken meat
    3. Egg yolk
    4. Fish oil
  2. Dairy products
    1. Whole milk
    2. Butter
    3. Margarine fortified with Vitamin A
  3. Dark green leafy vegetables
  4. Yellow-orange fruits and vegetables
    1. Apricot
    2. Cantaloupe
    3. Carrots
    4. Oranges
    5. Papayas
    6. Pumpkin
    7. Squash

Images: Related links to external sites (from Bing)

Related Studies

Cost: Medications

vitamin a (on 5/17/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
VITAMIN A & D OINTMENT Generic OTC $0.04 per gram

Ontology: Vitamin A (C0042839)

Definition (MEDLINEPLUS)

Vitamin A is an antioxidant. Antioxidants are substances that may protect your cells against the effects of free radicals. Free radicals are molecules produced when your body breaks down food, or by environmental exposures like tobacco smoke and radiation. Vitamin A also plays a role in your

  • Vision
  • Bone growth
  • Reproduction
  • Cell functions
  • Immune system

Vitamin A can come from plant or animal sources. Plant sources include colorful fruits and vegetables. Animal sources include liver and whole milk. Vitamin A is also added to foods like cereals.

Vegetarians, young children, and alcoholics may need extra Vitamin A. You might also need more if you have certain conditions, such as liver diseases, cystic fibrosis, and Crohn's disease. Check with your health care provider to see if you need to take vitamin A supplements.

NIH: National Institutes of Health Office of Dietary Supplements

Definition (MSH) 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.
Definition (PDQ) The fat soluble vitamin retinol. Vitamin A binds to and activates retinoid receptors (RARs), thereby inducing cell differentiation and apoptosis of some cancer cell types and inhibiting carcinogenesis. Vitamin A plays an essential role in many physiologic processes, including proper functioning of the retina, growth and differentiation of target tissues, proper functioning of the reproductive organs, and modulation of immune function. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=39735&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=39735&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C938" NCI Thesaurus)
Concepts Organic Chemical (T109) , Vitamin (T127) , Pharmacologic Substance (T121)
MSH D014801
SnomedCT 329237001, 270000007, 82622003, 82156005
LNC LP31687-4
English Vitamin A, Vitamin A product, Vitamin A USP, vitamin A (medication), retinol, VITAMIN A, Retinol, Vitamin A [Chemical/Ingredient], RETINOL, retinols, viatmin a, vitamin-a, vit a, a vitamin, vitamin A, retinol (vit A), Vitamin A product (product), Vitamin A preparation, Vitamin A (substance), Vitamin A preparation (product), Vitamin A preparation (substance), VIATMIN A
Swedish Vitamin A
Czech vitamin A
Finnish A-vitamiini
Japanese ビタミンA, ビタミンA1, 11-シス-レチノール, レチノール, 11-cis-レチノール
Spanish vitamina A (producto), preparado de vitamina A (producto), preparado de vitamina A, preparado de vitamina A (sustancia), vitamina A (sustancia), vitamina A, Vitamina A
Croatian Not Translated[Vitamin A]
Polish Retinol, Akseroftol, Witamina A
French Vitamine A, Rétinol
German Vitamin A
Italian Vitamina A
Portuguese Vitamina A