| Cholecalciferol | |
|---|---|
 |
 |
| IUPAC name | (3β,5Z,7E)-9,10-secocholesta- 5,7,10(19)-trien-3-ol |
| Other names | vitamin D3, activated 7-dehydrocholesterol. |
| Identifiers | |
| CAS number | [67-97-0] |
| EINECS number | |
| SMILES |
|
| Properties | |
| Molecular formula | C27H44O |
| Molar mass | 384.64 g/mol |
| Appearance | White, needle-like crystals |
| Melting point |
83–86 °C |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references |
|
Cholecalciferol is a form of Vitamin D, also called vitamin D3. It is structurally similar to steroids such as testosterone, cholesterol, and cortisol (though vitamin D3 itself is a secosteroid).
1g of pure vitamin D3 is 40 000 000 (40x106) IU, or in other words, one IU is 0.025 μg.
Contents |
Cholecalciferol has several forms:
7-Dehydrocholesterol is the precursor of vitamin D3 and only forms the vitamin after being exposed to solar UV radiation. This creates calciol.
Calciol is then hydroxylated in the liver to become calcidiol.
Next, calcidiol is once again hydroxylated, this time in the kidney, and becomes calcitriol. Calcitriol is the active hormone form of vitamin D3; for this reason vitamin D is often referred to as a prohormone.
Cholecalciferol is the form of vitamin D normally added during fortification of foods.[citation needed] Cholecalciferol is produced industrially by the irradiation of 7-dehydrocholesterol extracted from lanolin found in sheep's wool. In products where animal products are not desired, the alternative is to use ergocalciferol (also known as vitamin D2) derived from the fungal sterol ergosterol.
Healthy individuals absorb cholecalciferol and ergocalciferol approximately equally well[2], and while initial reports suggested that vitamin D3 was more potent in humans, the same journal has published newer research which contradicts those initial reports.[2] [3] The human body does not tolerate vitamin D3 as well as vitamin D2[citation needed], limiting the maximum efficacy of vitamin D3 supplementation compared to vitamin D2. Cholecalciferol is synthesized by the bone marrow of the skeletal system. Hepatic synthesis of 25-hydroxycholecalciferol is only loosely regulated, and blood levels of this molecule largely reflect the amount of vitamin D produced in the skin or ingested. In contrast, the activity of 1-alpha-hydroxylase in the kidney is tightly regulated and serves as the major control point in production of the active hormone.
Cholecalciferol is very sensitive to UV radiation and will rapidly, but reversibly break down to form supra-sterols, which can further irreversibly convert to tachysterol.
A 2008 study published in Cancer Research has shown the addition of vitamin D3 (along with calcium) to the diet of mice fed a regimen nutritionally similar to a new Western diet prevented colon cancer development.[4]
|
||||||||||||||
|
|||||