vitamin D

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vi·ta·min D

generic descriptor for all steroids exhibiting the biologic activity of ergocalciferol or cholecalciferol, the antirachitic vitamins popularly called the "sun-ray vitamins." They promote the proper use of calcium and phosphorus, thereby producing growth, together with proper bone and tooth formation, in young children; the sulfate, a water-soluble conjugate, is found in the aqueous phase of human milk; vitamin D1 is a 1:1 mixture of lumisterol and vitamin D2.

vitamin D

n.
A fat-soluble vitamin occurring in several forms, especially vitamin D2 or vitamin D3, required for normal growth of teeth and bones, and produced in general by ultraviolet irradiation of sterols found in milk, fish, and eggs.

vitamin D2

n.
A white crystalline compound, C28H44O, produced by ultraviolet irradiation of ergosterol. Also called calciferol, ergocalciferol.

vitamin D3

n.
A colorless crystalline compound, C27H44O, found in fish-liver oils, irradiated milk, and all irradiated animal foodstuffs. It has essentially the same biological activity as vitamin D2. Also called cholecalciferol.

vitamin D

a fat-soluble vitamin chemically related to the steroids and essential for the normal formation of bones and teeth and for the absorption of calcium and phosphorus from the GI tract. The vitamin is present in natural foods in small amounts, and requirements are usually met by artificial enrichment of various foods, especially milk and other dairy products, and exposure to sunlight. Ultraviolet rays activate a form of cholesterol in an oil of the skin that is converted to a form of the vitamin in the kidney. The natural foods containing vitamin D are of animal origin and include saltwater fish, especially salmon, sardines, and herring; organ meats; fish-liver oils; and egg yolk. Deficiency of the vitamin results in rickets in children, osteomalacia, osteoporosis, and osteodystrophy. Hypervitaminosis D produces a toxicity syndrome characterized by anorexia, vomiting, headache, drowsiness, diarrhea, and calcification of the soft tissues of the heart, blood vessels, renal tubules, and lungs. Treatment consists of discontinuing the vitamin dosage and initiating a low-calcium diet until symptoms resolve. See also calciferol, vitamin D3.

vitamin D

A mixture of several forms of vitamin D: Vitamin D3 is synthesised in the skin upon exposure to ultraviolet light; in contrast, vitamin D2 is obtained only from the diet. Both vitamins D2 and D3 are metabolised to 25-hydroxy vitamin D in the liver, and then to the active 1,25 dihydroxy form in the kidney. Vitamin D has a major role in the intestinal absorption of calcium, bone calcium balance and renal excretion of calcium, and is measured as part of a workup for hypocalcaemia, hypercalcaemia and hypophosphataemia.
 
Toxicity
Infants given excess vitamin D may develop atherosclerosis, severe mental retardation, facial dysmorphia, kidney damage, recurrent infections, anorexia, failure to thrive, and may die; as with adults ingesting megadoses of vitramin D, the damage is caused by excess calcium absorption.

vi·ta·min D

(vī'tă-min)
Generic descriptor for all steroids exhibiting the biologic activity of ergocalciferol or cholecalciferol, the antirachitic vitamins. They promote the proper use of calcium and phosphorus, thereby favoring proper bone and tooth formation and maintenance in children.

vitamin D

a fat-soluble molecule found in fish liver oils, and also produced in the skin when subjected to ultraviolet rays from sunlight. The main function of the vitamin is to increase the utilization of calcium and phosphorus in bones and teeth. A deficiency results in RICKETS in children and osteomalacia (bone-softening) in adults, particularly women after several pregnancies.

vitamin D

group of steroids with biological activity of cholecalciferol and ergocalciferol; promote calcium and phosphorus absorption; promote normal skeletal growth and bone/tooth formation
  • vitamin D derivatives see calcitriol, used in long-term treatment of hypocalcaemia

vitamin D,

n a fat-soluble vitamin found in fatty fish and fortified dairy products and synthesized by the body via sunlight. Has been used to remedy deficiencies (including depressed levels by taking medications such as cimetidine, corticosteroids, heparin, isoniazid, phenobarbital, phenytoin, primidone, rifampin, and valproic acid), to treat osteoporosis and polycystic ovaries (in conjunction with calcium supplementation), high blood pressure, type-1 diabetes, and psoriasis. Caution in patients with hyperparathyroidism or sarcoidosis, those taking calcium channel–blocking medications or thiazide diuretics. Caution is advised for children and pregnant or lactating women, for whom the maximum daily dose is 2000 IU (50 μg). Also called
calcipotriol (topical vitamin D3), cholecalciferol (vitamin D3), or
ergocalciferol (vitamin D2).

vi·ta·min D

(vī'tă-min)
Generic descriptor for all steroids exhibiting biologic activity of ergocalciferol or cholecalciferol, the antirachitic vitamins popularly called "sun-ray vitamins." They promote the proper use of calcium and phosphorus, thereby producing growth, together with proper bone and tooth formation, in young children.

vitamin D

a group of closely related steroids that have antirachitic properties. They commence as provitamins in both plants and animals and are converted by exposure to ultraviolet light. In plants ergosterol is converted to vitamin D2 (the provitamin ergocalciferol) by exposure to sunlight. In animals the provitamin 7-dehydrocalciferol (formed from cholesterol) is irradiated to form vitamin D3. Pharmaceutical vitamin D is manufactured by the ultraviolet irradiation of ergosterol.
A deficiency of vitamin D, from a nutritional deficiency of vitamin D2 and a deficiency of exposure to sunlight so that little vitamin D3 is formed, is characterized by the development of rickets in young animals or osteomalacia in adults.
Poisoning due to overdosing with vitamin D causes demineralization of bones and mineralization of soft tissues. The same effect is achieved by feeding on some plants. See enzootic calcinosis.

vitamin D D2
ergocalciferol.
vitamin D D3
cholecalciferol.

Patient discussion about vitamin D

Q. Recently I came to know after a test that I am vitamin D deficient so how much vitamin D should I take? I am 26 yrs old and I have fibromyalgia. Recently I came to know after a test that I am vitamin D deficient so how much vitamin D should I take?

A. what is a normal level of vitamin d for a 65 yr old woman?

Q. Should I give my baby girl vitamin D? I have a 4 month old baby girl. I have been reading that it is advised to give babies vitamin D. Is this true?

A. Yes, it is advised to give babies a vitamin D supplement. Vitamin D deficiency (not having enough) can be prevented by giving babies a daily supplement (drops) of vitamin D.
Babies need vitamin D for healthy growth and development. It helps them build strong, healthy bones and teeth.
Babies who don’t get enough vitamin D are at risk of getting rickets, a disease that affects the way bones grow and develop. Vitamin D can also help prevent certain illnesses in childhood or later in life.

Q. What food are rich with vitamin D? My son is 4 years old and the Doctor said he has vitamin D deficiency and advised me to give him a vitamin D supplement. I don't like the idea of giving him medicine, can't I just give him food which is rich with vitamin D and if so which foods are rich with vitamin D?

A. The best way to get vitamin D, the way that our bodies were designed to get the vast majority of our vitamin D, is from modest sun exposure. Going outside regularly will help your son to generate adequate amounts of vitamin D. Therefore, on top of the medicine the Doctor prescribed, have him go outside in the sun everyday for about 20 minutes. (Keep in mind that there is a concern of sunburn and increased risk of skin cancer with too much sun exposure, however.)

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