The findings will be presented at
the annual meeting of the American Society for Biochemistry and Molecular
being held in conjunction with the Experimental Biology 2013
meeting in Boston.
Vitamin D, also known as the sunshine vitamin, is
crucial for good bone health and muscle strength
as it reduces the risk of
fracture, osteomalacia (softening of the bone because of vitamin D deficiency),
osteoarthritis and osteoporosis. It also impacts the immune system to help
fight against cancer, autoimmune diseases (for example, celiac disease,
multiple sclerosis, rheumatoid arthritis, type 1 diabetes, Addison's disease,
etc), infectious diseases, type 2 diabetes and cardiovascular diseases.
Mushrooms are one of the few
plant food sources which contain ergosterol, a precursor to vitamin D2. The two
major physiological forms of active vitamin D for humans are ergocalciferol
(D2) and cholecalciferol (D3). Ergosterol, found in mushrooms is converted
to ergocalciferol or vitamin D2 by exposure to UV light
. Small amount of
vitamin D2 are synthesized in the mushrooms by exposure to naturally occurring
UV light during growing or processing.
The current recommended Adequate
Intake (AI) for Vitamin D for most adults is 5 microgram (200 IU).
Michael F. Holick, Professor
of Medicine, Physiology and Biophysics at Boston University School of Medicine
and the principal investigator of this study and his colleagues recruited 30
healthy adults who were given capsules containing 2,000 International Units
(IU) of vitamin D2; 2,000 IU of vitamin D3; or 2,000 IU of mushroom powder
containing vitamin D2 once a day for 12 weeks during the winter.
Initially, the participants'
vitamin D status, measured by serum 25-hydroxyvitamin D [25(OH)D], were not
significantly different among the groups.
The 25(OH)D levels gradually
increased and plateaued at 7 weeks and were maintained for the next 5 weeks in
all the three groups.
After 12 weeks (end of the
study), 25(OH)D levels were not significantly different in any of the group
suggesting that mushroom, mushroom powder and vitamin D supplements were
equally effective in maintaining and increasing vitamin D levels in the body.
"These results provide
evidence that ingesting mushrooms that 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,"
"Furthermore we found ingesting
mushrooms containing vitamin D2 was as effective in raising and maintaining a
healthy adult's vitamin D status as ingesting a supplement that contained
either vitamin D2 or vitamin D3," he added.
The researchers also found that
some mushrooms when exposed to UVB light produce vitamin D3 and vitamin D4 as
well thus providing the consumer with at least two additional vitamin Ds.
In their second presentation at
the same meeting, Dr Holick and his team will discuss how mushrooms make
vitamin D2 using a process similar to what occurs in human skin after sun
"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
pro-vitamin Ds in mushroom samples, including vitamin D3, which is also made in