|Trade names||Drisdol, Calcidol, others|
|Chemical and physical data|
|Molar mass||396.65 g/mol|
|3D model (Jmol)|
|Melting point||114 to 118 °C (237 to 244 °F)|
Ergocalciferol, also known as vitamin D2 and 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 used by mouth or injection into a muscle.
Excessive doses can result in increased urine production, high blood pressure, kidney stones, kidney failure, weakness, and constipation. If high doses are taken for a long period of time tissue calcification may occur. It is recommended that people on high doses have their blood calcium levels regularly checked. Normal doses are safe in pregnancy. It works by increasing the amount of calcium absorbed by the intestines and kidneys. Food in which it is found include some mushrooms.
Ergocalciferol was first described in 1936. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Ergocalciferol is available as a generic medication and over the counter. In the United Kingdom a typical dose costs the NHS less than 10 pounds a month. Certain foods such as breakfast cereal and margarine have ergocalciferol added to them in some countries.
Ergocalciferol may be used as a vitamin D supplement, and a 2011 clinical guideline considered ergocalciferol to be as effective as cholecalciferol (vitamin D3) which is produced naturally by the skin when exposed to ultraviolet light.
- Cladina arbuscula specimens grown under different natural conditions: The contents of vitamin D3 range from 0.67 to 2.04 μg/g dry matter in the thalli of C. arbuscula specimens grown under different natural conditions, while provitamin D3 could not be detected. The ranges for provitamin D2 and vitamin D2 were 89-146 and 0.22-0.55 μg/g dry matter, respectively, while the contents of provitamin D3 were below the detection limit (0.01 μg/g dry matter).
Fungus, from USDA nutrient database (per 100g) 
- Mushrooms, portobello, exposed to ultraviolet light, raw: Vitamin D (D2 + D3): 11.2 µg (446 IU)
- Mushrooms, portobello, exposed to ultraviolet light, grilled: Vitamin D (D2 + D3): 13.1 µg (524 IU)
- Mushrooms, shiitake, dried: Vitamin D (D2 + D3): 3.9 μg (154 IU)
- Mushrooms, shiitake, raw: Vitamin D (D2 + D3): 0.4 μg (18 IU)
- Mushrooms, portobello, raw: Vitamin D (D2 + D3): 0.3 μg (10 IU)
- Alfalfa (Medicago sativa subsp. sativa), shoot: 4.8 μg (192 IU) vitamin D2, 0.1 μg (4 IU) vitamin D3
Ergocalciferol is produced in fungi synthetically through irradiation of ergosterol. Human bioavailability of vitamin D2 from vitamin D2-enhanced button mushrooms via UV-B irradiation is effective in improving vitamin D status and not different from a vitamin D2 supplement. Vitamin D2 from UV-irradiated yeast baked into bread is bioavailable. By visual assessment or using a chromometer, no significant discoloration of irradiated mushrooms, as measured by the degree of "whiteness", was observed. Claims that a normal serving of mushrooms treated with ultraviolet light provides the equivalent of 3,500 International Units of vitamin D when exposed to ultraviolet light after harvest have gained popular attention.
Ergocalciferol is manufactured and marketed under various names, including Deltalin (Eli Lilly and Company), Drisdol (Sanofi-Synthelabo) and Calcidol (Patrin Pharma).
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