I didn't know this ...
http://www.drweil.com/drw/u/ART02935/Four-Unexpected-Food-Facts.htmlMushrooms make vitamin D in sunlight.
Most people are aware that the human body makes vitamin D in response to sunlight. Less known is the fact that mushrooms, even picked ones, can perform the same feat - which means that eating mushrooms that have been exposed to sunlight can be an excellent way to supplement your "D" levels.
In the summer of 2004, mycologist Paul Stamets discovered that the level of vitamin D in freshly picked, indoor- grown shiitake mushrooms rose from 110 IU (international units) to an astonishing 46,000 IU per 100 grams when the mushrooms were placed outdoors in the sun for just six hours with the gills facing up (when the gills were facing down, the level rose to 10,900 IU).
This means that eating just one gram of sun-treated shiitake - about one tenth of one mushroom - would give you 460 IU, close to the FDA's recommended daily dose of 400 IU, and about half of Dr. Weil's recommended 1,000 IU.
In his book, Mycelium Running: How Mushrooms Can Help Save the World, Stamets concluded, "(In) populations where vitamin D is seriously deficient, sun-exposed dried mushrooms can help address a serious health issue."