Scientists at Penn
State University (Pennsylvania,
USA) have found that
mushrooms are a better natural source of the antioxidant ergothioneine
than either of the two dietary sources previously believed to be best.
This result was discovered using a new and more sensitive-testing
approach that they have recently developed for fungi.
The researchers found that white button mushrooms, which are the most
commonly consumed type of mushroom in the U.S., have about 12 times
more of the antioxidant ergothioneine than wheat germ and 4 times more
than chicken liver (these food types being the top-rated
dietary sources of ergothioneine - according to previously available data).
Until the Penn State researchers developed their testing approach, known
as an "assay", there was no method employing the most sensitive modern
instrumentation and analytical techniques to quantify the amount of ergothioneine
in fungi.
The researchers say that their assay can be used for other
plants, too, not just mushrooms.
Joy Dubost, doctoral candidate in food science, who conducted the study,
says,
"Numerous studies have shown that consuming fruits and vegetables
which are high in antioxidants may reduce the risk of developing chronic
diseases. Ergothioneine, a unique metabolite produced by fungi, has been
shown to have strong antioxidant properties and to provide cellular protection
within the human body."
Dubost detailed the new assay and the amounts of ergothioneine in the
most common and exotic mushrooms typically available in U.S. food stores
in a paper presented at the
230th
American Chemical Society meeting in Washington, D. C. on 31st August 2005.
Her paper is
"Identification and Quantification
of Ergothioneine in Cultivated Mushrooms by Liquid Chromatography-Mass
Spectroscopy". Co-authors are Dr. Robert B. Beelman, professor of
food science; Dr. Devin G. Peterson, assistant professor of food science,
and Dr. Daniel J. Royse, professor of plant pathology.
The Penn State researchers found that among the most commonly consumed
mushrooms, portabellas and criminis have the most ergothioneine, followed
closely by the white buttons. A standard 3-ounce USDA serving of these
mushrooms, about the amount you'd put on a cheese steak or mushroom-topped
burger, supplies up to 5 milligrams.
The exotic mushrooms have even more ergothioneine. The same standard
serving size of shiitake, oyster, king oyster or maitake (hen of the
woods) can contain up to 13mg in a 3-ounce serving or about 40 times
as much as wheat germ.
Dubost notes that the levels of ergothioneine do not decrease when the
mushrooms are cooked.
In developing their new assay, the researchers adapted an assay used
to quantify the amount of ergothioneine in bovine ocular tissue. They
used high performance liquid chromatography (HPLC), a UV-VIS detector
and mass spectroscopy, instruments normally used in analytical chemistry.
The Penn State Experiment Station and Mushroom Endowment Fund supported
the study. The Mushroom Council and NutriCore Northeast are supporting
the Penn State's team's continuing research in this area.
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to inform visitors about current health issues, but not to endorse
any particular view or activity. Material in this news item
was first published by the American Association for Cancer Research
on 1st September 2005. For further information, please visit their
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