Posted on 05/23/2011 at 02:20:52 PM by Student BloggerBy: Ann L.
While sun exposure causes us to produce vitamin D in our skin, a little bit of ultraviolet light also boosts vitamin D production in a place you might not expect – fresh mushrooms.
Vitamin D is essential for building and maintaining strong bones, but it is notoriously difficult to obtain through dietary sources. Fatty fish are some of the few foods that naturally contain vitamin D. Most food sources of vitamin D such as milk and breakfast cereal have been fortified.
Interestingly mushrooms contain ergosterol, a precursor to vitamin D2. When mushrooms are exposed ultraviolet (UV) light, vitamin D2 levels increase dramatically (1).
Now, your regular grocery store mushrooms are grown in the dark, so they don't contain high amounts of vitamin D2, but companies have recently begun to produce special UV-treated mushrooms that have provide close to 400 IU of vitamin D per serving (2).
To put that in perspective, the IOM recently recommended that the recommended dietary allowance for vitamin D be increased from 200 IU to 600 IU. So in theory, you could come close to meeting your vitamin D requirement by consuming a single serving of these UV-treated mushrooms.
Of course, there are also those who take the do-it-yourself approach. A case study from the United Kingdom reported the case of an Indian man who presented with vitamin D deficiency as determined by serum 25-hydroxyvitamin D levels (3). The doctors prescribed a vitamin D supplement, but the patient took it upon himself to buy a UV light bulb from the hardware store and proceeded to expose mushrooms to UV light, cook them, and consume them every day for three months. After this time, which coincided with English winter, his serum vitamin D levels had increased from 17 nmol/L to 39 nmol/L, which is within the normal range.
Now, we could all buy UV light bulbs, but it's much more convenient to check out the produce section.
Have you seen UV-treated mushrooms in your grocery store?