Perhaps George Washington wouldn't have chopped
down his father's cherry tree if he knew what chemists now know.
They have identified a group of naturally occurring chemicals
abundant in cherries that could help lower blood sugar levels
in people with diabetes. In early laboratory studies using animal
pancreatic cells, the chemicals, called anthocyanins, increased
insulin production by 50 percent, according to a peer-reviewed
study scheduled to appear in the Jan. 5 issue of the American
Chemical Society's Journal of Agricultural and Food Chemistry.
ACS is the world's largest scientific society.
Anthocyanins are a class of plant pigments responsible for
the color of many fruits, including cherries. They also are
potent antioxidants, highly active chemicals that have been
increasingly associated with a variety of health benefits, including
protection against heart disease and cancer.
"It is possible that consumption of cherries and other fruits
containing these compounds [anthocyanins] could have a significant
impact on insulin levels in humans," says study leader Muralee
Nair, Ph.D., a natural products chemist at Michigan State University
in East Lansing. "We're excited with the laboratory results
so far, but more studies are needed." Michigan is the top cherry
producing state in the nation.
Until human studies are done on cherry anthocyanins, those
with diabetes should continue following their doctor's treatment
recommendations, including any medicine prescribed, and monitor
their insulin carefully, the researcher says. The compounds
show promise for both the prevention of type 2 (non-insulin-dependent)
diabetes, the most common type, and for helping control glucose
levels in those who already have diabetes, he adds.
While fresh cherries and fruits containing these anthocyanins
are readily available, medicinal products may be the most efficient
way to provide the beneficial compounds, according to Nair.
It's possible that anthocyanins eventually could be incorporated
into new products, such as pills or specialty juices that people
could take to help treat diabetes. Such disease-specific products
may take several more years to develop, he notes.
Scientists in Nair's laboratory have even developed a unique
process, patented by the university, for removing sugar from
fruit extracts that contain anthocyanins. This could lead to
"sugar-free" medicinal products for people with diabetes.
The current study, partially funded by the U.S. Department
of Agriculture, involved tart cherries (also known as sour cherries
or pie cherries), a popular variety in the United States, and
the Cornelian cherry, which is widely consumed in Europe. Nair
and his associates, B. Jayaprakasam, Ph.D., L.K. Olson, Ph.D.,
and graduate student S. K. Vareed, tested several types of anthocyanins
extracted from these cherries against mouse pancreatic-beta
cells, which normally produce insulin, in the presence of high
concentrations of glucose.
Insulin is the protein produced by the pancreas that helps
regulate blood sugar (glucose) levels. Compared to cells that
were not exposed to anthocyanins, exposed cells were associated
with a 50 percent increase in insulin levels, the researchers
say. The mechanism of action by which these anthocyanins boost
insulin production is not known, Nair says.
Nair and his colleagues are currently feeding anthocyanins
to a group of obese, diabetic mice to determine how the chemicals
influence insulin levels in live subjects. Results of these
tests are not yet available.
Although other fruits, including red grapes, strawberries and
blueberries, also contain anthocyanins, cherries appear to be
the most promising source of these compounds on the basis of
serving size, according to the researcher. The compounds are
found in both sweet and sour (tart) cherry varieties.
The potential benefits of cherries extend beyond diabetes.
Previous studies by the researcher found that certain anthocyanins
isolated from cherries have anti-inflammatory properties and
may be useful in fighting arthritis. Nair's colleagues have
found that cherries also may help fight colon cancer.
But people with diabetes are encouraged to use caution when
it comes to consuming maraschino cherries, the bright red candied
version that adorns ice cream and cocktails, Nair points out.
Many of the beneficial cherry pigments that were present in
the fresh fruit have been removed during processing, replaced
with food coloring, and extra sugar has been added.
The American Chemical Society is a nonprofit organization,
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of more than 159,000 chemists and chemical engineers. It publishes
numerous scientific journals and databases, convenes major research
conferences and provides educational, science policy and career
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and Columbus, Ohio.