Mushrooms are a good source of vitamin D2 and is as effective as taking vitamin D supplements. Vitamin D intake is crucial to the process of calcium absorption and maintaining healthy bones.

The new findings from researchers out of the Boston University School of Medicine appear in the journal Dermato-Endocrinology.  The research results were also presented Monday at the annual meeting of the American Society for Biochemistry and Microbiology.

Vitamin D helps maintain bone density to reduce the risk of fracture and bone disorders such as osteomalacia, osteoarthritis, and osteoporosis. It also helps fight the flu and similar infections, and reduces the risk of cancer, heart disease, depression and diabetes.

For the study, researchers studied the data obtained from 30 healthy adult participants who were asked to take vitamin D supplements or vitamin D2 mushroom powder. The participants were randomly selected to take either vitamin D2, vitamin D3 or the mushroom powder for 12 weeks. At the end of the study, there was no difference in the amount of vitmamin D found among the paricipants. 

"These results provide evidence that ingesting mushrooms which have been exposed to ultraviolet light and contain vitamin D2, are a good source of vitamin D that can improve the vitamin D status of healthy adults," Michael F. Holick, senior author of the study, said.

Mushrooms also provide two additional kinds vitamin D to consumers, including vitamin D3 which is one of the most important types of vitamin D for the body. The researchers also found that some mushrooms produce vitamin D3 and vitamin D4 when exposed to ultraviolet B (shortwave) rays. The process that occurs in human skin after being exposed to the sun is similar to the process in which the mushrooms make vitamin D2.

"Although it has been previously reported that mushrooms have the ability to produce both vitamin D2 and vitamin D4, through our own research we were able to detect several types of vitamin Ds and provitamin Ds in mushroom samples including vitamin D3 which is also made in human skin," Holick said.