Vitamin D

ABCDEFGHIJKLMNOPQRSTUVWXYZ
« Supplemental Index
Categories: Vitamin

Type: Compound
Vitamin: D
Name: Antirachitic Factor, Ergocalciferol, Cholecalciferol
RDA: 400 IU
Importance- to Body:
Functionally a hormone; increases calcium blood levels by enhancing absorption of calcium; in conjunction with PTH, mobilizes calcium from bones; both mechanisms serve calcium homeostasis of blood (essential for normal neuromuscular function, blood clotting, bone and took formation).
Distribution- in Body:
Group of chemically distinct sterols; concentrated in liver and to lesser extent in skin, kidneys, spleen, other tissues; stable to heat, light, acids, alkalis, oxidation.
Excess Effects:
1800 IU/day may be toxic to children, massive doses induce toxicity in adults; symptoms: Vomiting, Diarrhea, Weight Loss, Calcification of Soft Tissues, Renal Damage
Deficiency Effects:
Faulty mineralization of Bones and Teeth, Rickets in children, Osteomalacia in adults; Poor Muscle Tone, Restlessness, Irritability
Food Sources:
Fish Liver Oils, Eggs Yolk, Fortified Milk.
Environmental/Geographic Sources:
Vitamin D3 (cholecalciferol) is chief form in body cells; produced in skin by irradiation of 7- dehydrocholesterol by UV light; active form (1,25- dihydroxyvitamin D3) produced by chemical modification of vitamin D3 in liver, then kidneys.
Supplemental information:

Synonyms:
Antirachitic Factor,Ergocalciferol, Cholecalciferol
Related Articles:
  • Vitamin D and Skin
    In reality, the amount of time that a person has to spend in the sun to receive a sufficient dose of the D vitamin is extremely small and just a few minutes a day will be sufficient and not have any adverse effects from the amount of ultra-violet light received.
  • Supplemental: Calcium
    Necessary for proper bone structure, normal heart action, blood clotting, muscle contraction, excitability, nerve synapses, mental activity, buffer systems, glycogen metabolism
  • Supplemental: Phosphorus
    Necessary for proper bone structure, intermediary metabolism, buffers, membranes. Component of bones and teeth, nucleic acids, proteins, phospholipids, Combines with coenzymes in various metabolic processes; ATP
  • Shadows & Vitamin D
    The low UV index of winter sun makes it difficult, if not impossible, for us to make vitamin D, increasing the odds of colds, flu, and feeling blue.
  • Your Beauty Checklist
    No matter what your beauty challenges are, there are nutrients that can help you resolve them. Here we focus on supplements that can help restore luster to hair and revitalize skin.
Vitamin_D (Wikipedia)
For other uses, see Vitamin D (disambiguation).
Vitamin D
Drug class
Cholecalciferol-3d.png
Class identifiers
Use Rickets, osteoporosis, vitamin D deficiency
ATC code A11CC
Biological target vitamin D receptor
Clinical data
Drugs.com MedFacts Natural Products
External links
MeSH D014807
In Wikidata

Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and multiple other biological effects. In humans, the most important compounds in this group are vitamin D3 (also known as cholecalciferol) and vitamin D2 (ergocalciferol). Cholecalciferol and ergocalciferol can be ingested from the diet and from supplements. Only a few foods contain vitamin D. The major natural source of the vitamin is synthesis of cholecalciferol in the skin from cholesterol through a chemical reaction that is dependent on sun exposure (specifically UVB radiation). Dietary recommendations typically assume that all of a person's vitamin D is taken by mouth, as sun exposure in the population is variable and recommendations about the amount of sun exposure that is safe are uncertain in view of the skin cancer risk.

Vitamin D from the diet or skin synthesis is biologically inactive; enzymatic conversion (hydroxylation) in the liver and kidney is required for activation. As vitamin D can be synthesized in adequate amounts by most mammals exposed to sufficient sunlight, it is not an essential dietary factor, and so not technically a vitamin. Instead it could be considered as a hormone, with activation of the vitamin D pro-hormone resulting in the active form, calcitriol, which then produces effects via a nuclear receptor in multiple different locations. Cholecalciferol is converted in the liver to calcifediol (25-hydroxycholecalciferol); ergocalciferol is converted to 25-hydroxyergocalciferol. These two vitamin D metabolites (called 25-hydroxyvitamin D or 25(OH)D) are measured in serum to determine a person's vitamin D status. Calcifediol is further hydroxylated by the kidneys to form calcitriol (also known as 1,25-dihydroxycholecalciferol), the biologically active form of vitamin D. Calcitriol circulates as a hormone in the blood, having a major role regulating the concentration of calcium and phosphate, and promoting the healthy growth and remodeling of bone. Calcitriol also has other effects, including some on cell growth, neuromuscular and immune functions, and reduction of inflammation.

Vitamin D has a significant role in calcium homeostasis and metabolism. Its discovery was due to effort to find the dietary substance lacking in children with rickets (the childhood form of osteomalacia). Vitamin D supplements are given to treat or to prevent osteomalacia and rickets, but the evidence for other health effects of vitamin D supplementation in the general population is inconsistent. The effect of vitamin D supplementation on mortality is not clear, with one meta-analysis finding a small decrease in mortality in elderly people, and another concluding no clear justification exists for recommending supplementation for preventing many diseases, and that further research of similar design is unneeded in these areas.

« Supplemental Index