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Pronunciation | /ˌkoʊləkælˈsɪfərɒl/ |
Other names | vitamin D3 |
AHFS/Drugs.com | Professional Drug Facts |
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Routes of administration | By mouth, intramuscular |
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ECHA InfoCard | 100.000.612 |
Chemical and physical data | |
Formula | C27H44O |
Molar mass | 384.648 g·mol−1 |
3D model (JSmol) | |
Melting point | 83 to 86 °C (181 to 187 °F) |
Boiling point | 496.4 °C (925.5 °F) |
Solubility in water | Practically insoluble in water, freely soluble in ethanol, methanol and some other organic solvents. Slightly soluble in vegetable oils. |
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Cholecalciferol, also known as vitamin D3 or colecalciferol, is a type of vitamin D that is produced by the skin when exposed to UVB light; it is found in certain foods and can be taken as a dietary supplement. [3]
Cholecalciferol is synthesised in the skin following sunlight exposure. [4] It is then converted in the liver to calcifediol (25-hydroxycholecalciferol D), which is further converted in the kidney to calcitriol (1,25-dihydroxycholecalciferol D). [4] One of calcitriol’s most important functions is to promote calcium uptake by the intestines. [5] Cholecalciferol is present in food such as fatty fish, beef liver, eggs, and cheese. [6] [7] In some countries, cholecalciferol is also added to products like plants, cow milk, fruit juice, yogurt, and margarine. [6] [7]
Cholecalciferol can be taken orally as a dietary supplement to prevent vitamin D deficiency or as a medication to treat associated diseases, including rickets. [8] [9] It is also used in the management of familial hypophosphatemia, hypoparathyroidism that is causing low blood calcium, and Fanconi syndrome. [9] [10] Vitamin-D supplements may not be effective in people with severe kidney disease. [11] [10] Excessive doses in humans can result in vomiting, constipation, muscle weakness, and confusion. [5] Other risks include kidney stones. [11] Doses greater than 40000 IU (1000 μg) per day are generally required before high blood calcium occurs. [12] Normal doses, 800–2000 IU per day, are safe in pregnancy. [5]
Cholecalciferol was first described in 1936. [13] It is on the World Health Organization's List of Essential Medicines. [14] In 2022, it was the 62nd most commonly prescribed medication in the United States, with more than 10 million prescriptions. [15] [16] Cholecalciferol is available as a generic medication. [10] [17] [18]
Cholecalciferol (vitamin D3) appears to stimulate the body's interferon type I signaling system that protects against bacteria and viruses, unlike vitamin D2. [19]
Cholecalciferol is a form of vitamin D which is naturally synthesized in skin and functions as a pro-hormone, being converted to calcitriol. This is important for maintaining calcium levels and promoting bone health and development. [4] As a medication, cholecalciferol may be taken as a dietary supplement to prevent or to treat vitamin D deficiency. One gram is 40000000 (40×106) IU, equivalently 1 IU is 0.025 μg, or 25 ng. Dietary reference intake values for vitamin D (ergocalciferol, which is D2, or cholecalciferol, which is D3), or both, have been established and recommendations vary depending on the country:
Low levels of vitamin D3 are more commonly found in individuals living in northern latitudes or with other reasons for a lack of regular sun exposure, including being housebound, frail, elderly, or obese, having darker skin, and wearing clothes that cover most of the skin. [23] [24] Supplements are recommended for these groups of people. [24]
The Institute of Medicine in 2010 recommended a maximum uptake of vitamin D of 4000 IU/d, finding that the dose for lowest observed adverse effect level is 40,000 IU daily for at least 12 weeks, [25] and that there was a single case of toxicity above 10000 IU after more than seven years of daily intake; this case of toxicity occurred in circumstances that have led other researchers to dispute whether it is a credible case to consider when making vitamin D intake recommendations. [25] Patients with severe vitamin D deficiency will require treatment with a loading dose; its magnitude can be calculated based on the actual serum 25-hydroxy-vitamin D level and body weight. [26]
There are conflicting reports concerning the relative effectiveness of cholecalciferol (D3) versus ergocalciferol (D2), with some studies suggesting less efficacy of D2, and others showing no difference. There are differences in absorption, binding and inactivation of the two forms, with evidence usually favoring cholecalciferol in raising levels in blood, although more research is needed. [27]
A much less common use of cholecalciferol therapy in rickets utilizes a single large dose and has been called stoss therapy. [28] [29] [30] Treatment is given either orally or by intramuscular injection of 300000 IU (7500 μg) to 500000 IU (12500 μg = 12.5 mg), in a single dose, or sometimes in two to four divided doses. There are concerns about the safety of such large doses. [30]
Low circulating vitamin D levels have been associated with lower total testosterone levels in males. Vitamin D supplementation could potentially improve total testosterone concentration, although more research is needed. [31]
A meta-analysis of 2007 concluded that daily intake of 1000 to 2000 IU/d of vitamin D3 could reduce the incidence of colorectal cancer with minimal risk. [32] Also a 2008 study published in Cancer Research has shown the addition of vitamin D3 (along with calcium) to the diet of some mice fed a regimen similar in nutritional content to a new Western diet with 1000 IU cholecalciferol per day prevented colon cancer development. [33] In humans, with 400 IU daily, there was no effect of cholecalciferol supplements on the risk of colorectal cancer. [34]
Supplements are not recommended for prevention of cancer as any effects of cholecalciferol are very small. [35] Although correlations exist between low levels of blood serum cholecalciferol and higher rates of various cancers, multiple sclerosis, tuberculosis, heart disease, and diabetes, [36] the consensus is that supplementing levels is not beneficial. [37] It is thought that tuberculosis may result in lower levels. [38] It, however, is not entirely clear how the two are related. [39]
Cholecalciferol is one of the five forms of vitamin D. [40] Cholecalciferol is a secosteroid, that is, a steroid molecule with one ring open. [41]
By itself cholecalciferol is inactive. It is converted to its active form by two hydroxylations: the first in the liver, by CYP2R1 or CYP27A1, to form 25-hydroxycholecalciferol (calcifediol, 25-OH vitamin D3). The second hydroxylation occurs mainly in the kidney through the action of CYP27B1 to convert 25-OH vitamin D3 into 1,25-dihydroxycholecalciferol (calcitriol, 1,25-(OH)2vitamin D3). All these metabolites are bound in blood to the vitamin D-binding protein. The action of calcitriol is mediated by the vitamin D receptor, a nuclear receptor which regulates the synthesis of hundreds of proteins and is present in virtually every cell in the body. [4]
Click on icon in lower right corner to open.
Click on genes, proteins and metabolites below to link to respective articles. [§ 1]
7-Dehydrocholesterol is the precursor of cholecalciferol. [4] Within the epidermal layer of skin, 7-dehydrocholesterol undergoes an electrocyclic reaction as a result of UVB light at wavelengths between 290 and 310 nm, with peak synthesis occurring at 293 nm. [42] This results in the opening of the vitamin precursor B-ring through a conrotatory pathway making previtamin D3 (pre-cholecalciferol). [43] In a process which is independent of UV light, the pre-cholecalciferol then undergoes a [1,7] antarafacial sigmatropic rearrangement [44] and therein finally isomerizes to form vitamin D3.
The active UVB wavelengths are little present in sunlight, and sufficient amounts of cholecalciferol can be produced with moderate exposure of the skin, depending on the strength of the sun. [42] Time of day, season, latitude, and altitude affect the strength of the sun, and pollution, cloud cover or glass all reduce the amount of UVB exposure. Exposure of face, arms and legs, averaging 5–30 minutes twice per week, may be sufficient, but the darker the skin, and the weaker the sunlight, the more minutes of exposure are needed. Vitamin D overdose is impossible from UV exposure; the skin reaches an equilibrium where the vitamin degrades as fast as it is created. [42]
Cholecalciferol can be produced in skin from the light emitted by the UV lamps in tanning beds, which produce ultraviolet primarily in the UVA spectrum, but typically produce 4% to 10% of the total UV emissions as UVB. Levels in blood are higher in frequent users of tanning salons. [42]
A 293 nanometer UVB light emitting diode (LED) was found to be 2.4 times more efficient in producing vitamin D3 than the sun in less than 1⁄60 the time. (https://pubmed.ncbi.nlm.nih.gov/28904394/).
Whether cholecalciferol and all forms of vitamin D are by definition "vitamins" can be disputed, since the definition of vitamins includes that the substance cannot be synthesized by the body and must be ingested. Cholecalciferol is synthesized by the body during UVB radiation exposure. [4]
The three steps in the synthesis and activation of vitamin D3 are regulated as follows:
Cholecalciferol is produced industrially for use in vitamin supplements and to fortify foods. As a pharmaceutical drug it is called cholecalciferol (USAN) or colecalciferol (INN, BAN). It is produced by the ultraviolet irradiation of 7-dehydrocholesterol extracted from lanolin found in sheep's wool. [45] Cholesterol is extracted from wool grease and wool wax alcohols obtained from the cleaning of wool after shearing. The cholesterol undergoes a four-step process to make 7-dehydrocholesterol, the same compound that is produced in the skin of animals. The 7-dehydrocholesterol is then irradiated with ultraviolet light. Some unwanted isomers are formed during irradiation: these are removed by various techniques, leaving a resin which melts at about room temperature and usually has a potency of 25000000 to 30000000 International Units/gram.
Cholecalciferol is also produced industrially for use in vitamin supplements from lichens, which is suitable for vegans. [46] [47]
Cholecalciferol is very sensitive to UV radiation and will rapidly, but reversibly, break down to form supra-sterols, which can further irreversibly convert to ergosterol.[ citation needed ]
Rodents are somewhat more susceptible to high doses than other species, and cholecalciferol has been used in poison bait for the control of these pests. [48] [18]
The mechanism of high dose cholecalciferol is that it can produce "hypercalcemia, which results in systemic calcification of soft tissue, leading to kidney failure, cardiac abnormalities, hypertension, CNS depression, and GI upset. Signs generally develop within 18–36 h of ingestion and can include depression, loss of appetite, polyuria, and polydipsia." [17] High-dose cholecalciferol will tend to rapidly accumulate in adipose tissue yet release more slowly [49] which will tend to delay time of death for several days from the time that high-dose bait is introduced. [48]
In New Zealand, possums have become a significant pest animal. For possum control, cholecalciferol has been used as the active ingredient in lethal baits. [50] The LD50 is 16.8 mg/kg, but only 9.8 mg/kg if calcium carbonate is added to the bait. [51] [52] Kidneys and heart are target organs. [53] LD50 of 4.4 mg/kg has been reported in rabbits, with lethality to almost all rabbits ingesting doses greater than 15 mg/kg. [54] Toxicity has been reported across a wide range of cholecalciferol dosages, with LD50 as high as 88 mg/kg or LDLo as low as 2 mg/kg reported for dogs. [55]
Researchers have reported that the compound is less toxic to non-target species than earlier generations of anticoagulant rodenticides (Warfarin and congeners) or Bromethalin, [56] and that relay toxicosis (poisoning by eating a poisoned animal) has not been documented. [17] Nevertheless, the same source reports that use of cholecalciferol in rodenticides may still pose a significant hazard to other animals, such as dogs and cats, when rodenticide bait or other forms of cholecalciferol are directly ingested. [17]
Rickets, scientific nomenclature: rachitis, is a condition that results in weak or soft bones in children and is caused by either dietary deficiency or genetic causes. Symptoms include bowed legs, stunted growth, bone pain, large forehead, and trouble sleeping. Complications may include bone deformities, bone pseudofractures and fractures, muscle spasms, or an abnormally curved spine.
Vitamin K is a family of structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. The human body requires vitamin K for post-synthesis modification of certain proteins that are required for blood coagulation or for controlling binding of calcium in bones and other tissues. The complete synthesis involves final modification of these so-called "Gla proteins" by the enzyme gamma-glutamyl carboxylase that uses vitamin K as a cofactor.
7-Dehydrocholesterol (7-DHC) is a zoosterol that functions in the serum as a cholesterol precursor, and is photochemically converted to vitamin D3 in the skin, therefore functioning as provitamin-D3. The presence of this compound in human skin enables humans to manufacture vitamin D3 (cholecalciferol). Upon exposure to ultraviolet UV-B rays in the sun light, 7-DHC is converted into vitamin D3 via previtamin D3 as an intermediate isomer. It is also found in the milk of several mammalian species. Lanolin, a waxy substance that is naturally secreted by wool-bearing mammals, contains 7-DHC which is converted into vitamin D by sunlight and then ingested during grooming as a nutrient. In insects 7-dehydrocholesterol is a precursor for the hormone ecdysone, required for reaching adulthood. 7-DHC was discovered by Nobel-laureate organic chemist Adolf Windaus.
Calcium metabolism is the movement and regulation of calcium ions (Ca2+) in (via the gut) and out (via the gut and kidneys) of the body, and between body compartments: the blood plasma, the extracellular and intracellular fluids, and bone. Bone acts as a calcium storage center for deposits and withdrawals as needed by the blood via continual bone remodeling.
Ergocalciferol, also known as vitamin D2 and nonspecifically calciferol, is a type of vitamin D found in food and used as a dietary supplement. As a supplement it is used to prevent and treat vitamin D deficiency. This includes vitamin D deficiency due to poor absorption by the intestines or liver disease. It may also be used for low blood calcium due to hypoparathyroidism. It is taken by mouth or via injection into a muscle.
β-Carotene (beta-carotene) is an organic, strongly colored red-orange pigment abundant in fungi, plants, and fruits. It is a member of the carotenes, which are terpenoids (isoprenoids), synthesized biochemically from eight isoprene units and thus having 40 carbons.
Rodenticides are chemicals made and sold for the purpose of killing rodents. While commonly referred to as "rat poison", rodenticides are also used to kill mice, woodchucks, chipmunks, porcupines, nutria, beavers, and voles. Despite the crucial roles that rodents play in nature, there are times when they need to be controlled.
Calcitriol is a hormone and the active form of vitamin D, normally made in the kidney. It is also known as 1,25-dihydroxycholecalciferol. It binds to and activates the vitamin D receptor in the nucleus of the cell, which then increases the expression of many genes. Calcitriol increases blood calcium mainly by increasing the uptake of calcium from the intestines.
Vitamin D toxicity, or hypervitaminosis D, is the toxic state of an excess of vitamin D. The normal range for blood concentration in adults is 20 to 50 nanograms per milliliter (ng/mL).
Nutrition and pregnancy refers to the nutrient intake, and dietary planning that is undertaken before, during and after pregnancy. Nutrition of the fetus begins at conception. For this reason, the nutrition of the mother is important from before conception as well as throughout pregnancy and breastfeeding. An ever-increasing number of studies have shown that the nutrition of the mother will have an effect on the child, up to and including the risk for cancer, cardiovascular disease, hypertension and diabetes throughout life.
Calcifediol, also known as calcidiol, 25-hydroxycholecalciferol, or 25-hydroxyvitamin D3 (abbreviated 25(OH)D3), is a form of vitamin D produced in the liver by hydroxylation of vitamin D3 (cholecalciferol) by the enzyme vitamin D 25-hydroxylase. Calcifediol can be further hydroxylated by the enzyme 25(OH)D-1α-hydroxylase, primarily in the kidney, to form calcitriol (1,25-(OH)2D3), which is the active hormonal form of vitamin D.
Previtamin D3 is an intermediate in the production of cholecalciferol (vitamin D3).
CYP2R1 is cytochrome P450 2R1, an enzyme which is the principal vitamin D 25-hydroxylase. In humans it is encoded by the CYP2R1 gene located on chromosome 11p15.2. It is expressed in the endoplasmic reticulum in liver, where it performs the first step in the activation of vitamin D by catalyzing the formation of 25-hydroxyvitamin D.
Vitamin D5 (sitocalciferol) is a form of vitamin D.
Vitamin D deficiency or hypovitaminosis D is a vitamin D level that is below normal. It most commonly occurs in people when they have inadequate exposure to sunlight, particularly sunlight with adequate ultraviolet B rays (UVB). Vitamin D deficiency can also be caused by inadequate nutritional intake of vitamin D; disorders that limit vitamin D absorption; and disorders that impair the conversion of vitamin D to active metabolites, including certain liver, kidney, and hereditary disorders. Deficiency impairs bone mineralization, leading to bone-softening diseases, such as rickets in children. It can also worsen osteomalacia and osteoporosis in adults, increasing the risk of bone fractures. Muscle weakness is also a common symptom of vitamin D deficiency, further increasing the risk of fall and bone fractures in adults. Vitamin D deficiency is associated with the development of schizophrenia.
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, along with numerous other biological functions. In humans, the most significant compounds within this group are vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol).
Michael F. Holick is an American adult endocrinologist, specializing in vitamin D, such as the identification of both calcidiol, the major circulating form of vitamin D, and calcitriol, the active form of vitamin D. His work has been the basis for diagnostic tests and therapies for vitamin D-related diseases. He is a professor of medicine at the Boston University Medical Center and editor-in-chief of the journal Clinical Laboratory.
Associations have been shown between vitamin D levels and several respiratory tract infections suggesting that vitamin D deficiency may predispose to infection. Outbreaks of respiratory infections occur predominantly during months associated with lower exposure to the sun. The Institute of Medicine concluded in a 2011 report that the existing data were "not consistently supportive of a causal role" for vitamin D in reducing the risk of infection. Other studies suggest that vitamin D supplementation can provide a protective role in reducing the incidence or severity of respiratory infections.
Vitamin D deficiency has become a worldwide health epidemic with clinical rates on the rise. In the years of 2011–12, it was estimated that around 4 million adults were considered deficient in Vitamin D throughout Australia. The Australian Bureau of Statistics (ABS) found 23%, or one in four Australian adults suffer from some form of Vitamin D deficiency. Outlined throughout the article are the causes of increase through subgroups populations, influencing factors and strategies in place to control deficiency rates throughout Australia.
As in the human practice of veganism, vegan dog foods are those formulated with the exclusion of ingredients that contain or were processed with any part of an animal, or any animal byproduct. Vegan dog food may incorporate the use of fruits, vegetables, cereals, legumes including soya, nuts, vegetable oils, as well as any other non-animal based foods.
Incidence of vitamin D3 toxicosis in animals is relatively less than that of anticoagulant and bromethalin toxicosis. Relay toxicosis from vitamin D3 has not been documented.
0.15% cholecalciferol bait appears to have application for pocket gopher control.' Cholecalciferol can be a single high-dose toxicant or a cumulative multiple low-dose toxicant.
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: CS1 maint: overridden setting (link)Cholecalciferol is an acute (single-feeding) and/or chronic (multiple-feeding) rodenticide toxicant with unique activity for controlling commensal rodents including anticoagulant-resistant rats. Cholecalciferol differs from conventional acute rodenticides in that no bait shyness is associated with consumption and time to death is delayed, with first dead rodents appearing 3–4 days after treatment.
We investigated the effect of oral high-dose cholecalciferol on plasma and adipose tissue cholecalciferol and its subsequent release, and on plasma 25-hydroxyvitamin D (25(OH)D). ... We conclude that orally-administered cholecalciferol rapidly accumulates in adipose tissue and that it is very slowly released while there is energy balance.
Use of cholecalciferol as a rodenticide in bait lowered the risk of secondary poisoning and minimized the toxicity of non-target species