Hops
compounds help with metabolic syndrome while reducing microbiome diversity
Oregon
State University
Compounds
from hops may combat metabolic syndrome by changing the gut microbiome and
altering the metabolism of acids produced in the liver, new research at Oregon
State University suggests.
The findings,
published in Molecular
Nutrition and Food Research, are a key advance in understanding how
xanthohumol, a compound that contributes to hops' flavor, and its derivatives
work.
That is an important step toward improving the lives of the estimated 35% of U.S. adults who suffer from metabolic syndrome.
That is an important step toward improving the lives of the estimated 35% of U.S. adults who suffer from metabolic syndrome.
The study builds
on earlier research at OSU that found xanthohumol, often abbreviated to XN, and
two hydrogenated derivatives, DXN and TXN, can likely improve cognitive and
other functions in people with the syndrome.
People are
considered to have metabolic syndrome if they have at least two of the
following conditions: abdominal obesity, high blood pressure, high blood sugar,
low levels of "good" cholesterol and high levels of triglycerides.
A diet high in saturated fat and refined sugars causes chronic low-grade inflammation that contributes to the development of metabolic syndrome; the syndrome is associated with cognitive dysfunction and dementia as well as being a major risk factor for cardiovascular disease and Type 2 diabetes.
In the previous study, testing in a mouse model showed that XN, DXN and TXN improve glucose intolerance, insulin resistance and sensitivity to leptin -- a hormone that tells you to feel full when you have eaten enough and also helps regulate energy expenditure. All of these changes are thought to be beneficial in the fight against metabolic syndrome.
In the most
recent research, laboratory animals were given a high-fat diet exclusively, or
a high-fat diet that included XN, TXN or DXN. Scientists then measured the
compounds' effects on bile acids -- bile is a fluid produced by the liver that
helps with the digestion of fats -- tissue inflammation and gut microbiome
composition.
Results show
that each of the hops compounds decreased the amount and diversity of microbes,
reduced inflammation and changed bile acid metabolism -- there was a reduction
in secondary bile acid production and an increase of conjugated bile acids,
which are indicators of improved energy metabolism, glucose metabolism and
cholesterol metabolism.
"Changes in
gut microbiota and bile acid metabolism seem to explain at least partially why
XN and its derivatives lead to improvements in obesity and other aspects of
metabolic syndrome," said the study's corresponding author, Adrian
Gombart, professor of biochemistry and biophysics in the College of Science and
a principal investigator at OSU's Linus Pauling Institute.
"But this is not necessarily cause and effect -- we need to know which changes to the microbiota are beneficial."
"But this is not necessarily cause and effect -- we need to know which changes to the microbiota are beneficial."
Collaborator
Fred Stevens, professor of pharmaceutical sciences in the OSU College of
Pharmacy and also a principal investigator at the Linus Pauling Institute,
found it surprising that the benefits were accompanied by a decrease rather
than increase in microbiome diversity.
Gombart noted
that the hops compounds have previously been shown to have antimicrobial
properties, "so they may be killing off certain bugs that aren't
beneficial and preserving other ones that are."
Stevens added:
"And further research will try to determine what the compounds are doing
directly to the body in addition to what they're doing through the gut
microbiota. These compounds must be having some direct effect on the body
through their specific molecular size and shape."