Dermato-Endocrinology Jan 2013
Raphael-John H. Keegan, Zhiren Lu, Jaimee M. Bogusz, Jennifer E. Williams, Michael F Holick*
1 Department of Medicine; Section of Endocrinology, Nutrition, and Diabetes; Vitamin D, Skin and Bone Research Laboratory; Boston University Medical Center; Boston, MA USA
Michael F Holick Corresponding author: mfholick at bu.edu
Mushrooms exposed to sunlight or UV radiation are an excellent source of dietary vitamin D2 because they contain high concentrations of the vitamin D precursor, provitamin D2. When mushrooms are exposed to UV radiation, provitamin D2 is converted to previtamin D2. Once formed, previtamin D2 rapidly isomerizes to vitamin D2 in a similar manner that previtamin D3 isomerizes to vitamin D3 in human skin. Continued exposure of mushrooms to UV radiation results in the production of lumisterol2 and tachysterol2. It was observed that the concentration of lumisterol2 remained constant in white button mushrooms for up to 24 h after being produced. However, in the same mushroom tachysterol2 concentrations rapidly declined and were undetectable after 24 h. Shiitake mushrooms not only produce vitamin D2 but also produce vitamin D3 and vitamin D4. A study of the bioavailability of vitamin D2 in mushrooms compared with the bioavailability of vitamin D2 or vitamin D3 in a supplement revealed that ingestion of 2000 IUs of vitamin D2 in mushrooms is as effective as ingesting 2000 IUs of vitamin D2 or vitamin D3 in a supplement in raising and maintaining blood levels of 25-hydroxyvitamin D which is a marker for a person's vitamin D status. Therefore, mushrooms are a rich source of vitamin D2 that when consumed can increase and maintain blood levels of 25-hydroxyvitamin D in a healthy range. Ingestion of mushrooms may also provide the consumer with a source of vitamin D3 and vitamin D4.
Note: mushrooms must be exposed to the sun/uv to develope any Vitamin D2
See also VitaminDWiki
- Overview Vitamin D3 not D2
- Vitamin D3 for Vegans - many studies
- Mushroom vitamin D2 update – 200 to 1000 IU per 100 gram – June 2011
- Soup with UVB irradiated mushrooms added 8 ng to vitamin D blood levels – May 2011
- Statement: 1/3 of herbs from Far East were made with sun-dried mushrooms. Now all the mushrooms in herbs are oven-dried (= no vitamin D)