Thank
hungry gut microbes
The health benefits of
eating dark chocolate have been extolled for centuries, but the exact reason
has remained a mystery -- until now.
Researchers have just reported that
certain bacteria in the stomach gobble the chocolate and ferment it into
anti-inflammatory compounds that are good for the heart.
"We found that
there are two kinds of microbes in the gut: the 'good' ones and the 'bad'
ones," explained Maria Moore, an undergraduate student and one of the
study's researchers.
"The good
microbes, such as Bifidobacterium and lactic acid bacteria, feast on
chocolate," she said. "When you eat dark chocolate, they grow and
ferment it, producing compounds that are anti-inflammatory." The other
bacteria in the gut are associated with inflammation and can cause gas,
bloating, diarrhea and constipation. These include some Clostridia and some E. coli.
"When these
compounds are absorbed by the body, they lessen the inflammation of
cardiovascular tissue, reducing the long-term risk of stroke," said John
Finley, Ph.D., who led the work. He said that this study is the first to look
at the effects of dark chocolate on the various types of bacteria in the
stomach. The researchers are with Louisiana State University.
The team tested three
cocoa powders using a model digestive tract, composed of a series of modified
test tubes, to simulate normal digestion. They then subjected the
non-digestible materials to anaerobic fermentation using human fecal bacteria,
according to Finley.
He explained that cocoa
powder, an ingredient in chocolate, contains several polyphenolic, or
antioxidant, compounds such as catechin and epicatechin, and a small amount of
dietary fiber. Both components are poorly digested and absorbed, but when they
reach the colon, the desirable microbes take over.
"In our study we found
that the fiber is fermented and the large polyphenolic polymers are metabolized
to smaller molecules, which are more easily absorbed. These smaller polymers
exhibit anti-inflammatory activity," he said.
Finley also noted that
combining the fiber in cocoa with prebiotics is likely to improve a person's
overall health and help convert polyphenolics in the stomach into
anti-inflammatory compounds.
"When you ingest prebiotics, the beneficial
gut microbial population increases and outcompetes any undesirable microbes in
the gut, like those that cause stomach problems," he added. Prebiotics are
carbohydrates found in foods like raw garlic and cooked whole wheat flour that
humans can't digest but that good bacteria like to eat. This food for your
gut's helpful inhabitants also comes in dietary supplements.
Finley said that people
could experience even more health benefits when dark chocolate is combined with
solid fruits like pomegranates and acai. Looking to the future, he said that
the next step would be for industry to do just that.
This study was
supported by the Louisiana State College of Agriculture and a Louisiana
AgCenter Undergraduate Research Grant.
Story Source:
The above story is
based on materials provided
by American Chemical Society.Note:
Materials may be edited for content and length.
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American Chemical Society.
"Precise reason for health benefits of dark chocolate: Thank hungry gut
microbes." Science Daily, 18
March 2014. <www.sciencedaily.com/releases/2014/03/140318154725.htm>.
