EMBARGOED
FOR RELEASE UNTIL
August 8, 2007
APS Contact
Donna Krupa
Office:
(301) 634-7253
Cell: (703) 967-2751
dkrupa@the-aps.org
Grapes, Soy And Kudzu Blunt
Some Menopausal Side Effects
Memory
loss, hypertension and insulin resistance reduced in several animal studies
Austin, TX – Menopausal women are at relatively
high risk for memory loss, high blood pressure (hypertension) and diabetes.
A decade ago, the standard treatment for these problems was long-term
hormone replacement therapy (HRT). Since then, studies have shown that
extensive use of HRT is associated with significant adverse effects. As a
result, alternatives have been sought. Certain naturally occurring edible
compounds found in plants – dietary polyphenols – have been shown to have
some beneficial effects similar to HRT but without the appreciable adverse
effects. Grape, soy and kudzu are dietary polyphenols. One research lab
investigating them through several studies has found they can blunt
cognitive loss, hypertension and insulin resistance in an experimental
model.
These and related studies are being led by physiologist
J. Michael Wyss, Department of Cell Biology, University of Alabama at
Birmingham (UAB), Birmingham, AL. Dr. Wyss will be discussing his work,
entitled “The Role of Estrogens and Polyphenols in Hypertension and
Diabetes,” at the upcoming conference, Sex and Gender in
Cardiovascular-Renal Physiology and Pathophysiology, being held August
9-12, 2007 at the Hyatt Regency Austin on Town Lake, Austin, TX. The meeting
is the second scientific event to be sponsored by the American Physiological
Society (APS;
www.The-APS.org) this year.
Incorporated in Dr. Wyss’ presentation are results from
the following studies:
Study 1: Grapes, Cognitive Enhancement and
Hypertension
The research team examined
whether grape polyphenols were associated with reduced cognitive dysfunction
and a lower incidence of high blood pressure. They found that the effect of
the polyphenols on working and reference memory errors indicated that both
short-term (working memory) and long-term (reference memory) were
beneficially and nearly equally enhanced by grape polyphenols.
However, a more formal test
of this hypothesis, using other indices of these forms of memory, is needed
before the effect can be fully interpreted.
The researchers also tested
the hypothesis that grape seed polyphenols reduced salt-sensitive
hypertension in young, estrogen-depleted rats. After ten weeks on specific
diets, grape seed supplementation significantly reduced arterial pressure in
the rats fed a high salt diet, compared to controls. The results indicate
that grape seed polyphenols decrease arterial pressure in rats, probably via
an antioxidant mechanism. The published results of this study are the first
to demonstrate that dietary grape seed polyphenols blunt memory loss and
hypertension in an animal model.
Study 2: Soy and Hypertension
Previous studies from the
Wyss lab indicate that polyphenols in soy diets protect against hypertension
in estrogen-depleted/ovariectomized rats. Specifically, they have found that
estrogen deprivation (by surgical removal of the ovaries) only modestly
increases arterial pressure in hypertensive rats. However, in estrogen
depleted rats, the removal of soy polyphenols from the diet results in a
large increase in arterial pressure, putting the animal at a much greater
risk of stroke and other cardiovascular complications. The precise mechanism
by which soy interacts with the blood to affect hypertension is not yet
known.
Study 3: Kudzu and Insulin Resistance
The UAB researchers have
examined kudzu, a vine growing in the southeast United States. Their
research, and others’, shows kudzu root extract blunts a significant percent
of the blood pressure rise that occurs in rats placed on a high salt diet.
Kudzu has also been shown to reduce blood glucose, insulin and leptin in
this animal model of insulin resistance (a precursor to type 2 diabetes).
Glucose tolerance and sensitivity are improved some 20 percent in chronic
studies and about 50 percent when kudzu and glucose are administered
simultaneously.
Conclusion
These studies demonstrate that three polyphenols –
grape, soy and kudzu – blunt hypertension, insulin resistance and cognitive
decline when estrogen is not present in female rats. According to Dr. Wyss,
“It is unlikely that these polyphenols could eventually provide effective
stand-alone therapy for post-menopausal women, but in the future they may
provide effective adjunct therapy that complements the use of lower doses of
traditional pharmaceutical compounds.”
***
The American
Physiological Society (APS;
www.The-APS.org) has been an integral part of the scientific discovery
process since it was established in 1887. Physiology is the study of
how molecules, cells, tissues and organs function to create health or
disease.
NOTE TO EDITORS: The APS meeting is being held
August 9-12, 2007 at the Hyatt Regency Austin on Town Lake, Austin, TX.
Members of the media are invited to attend the sessions. To schedule an
interview with Dr. Wyss, please contact Donna Krupa at 301.634.7209
(direct dial), 703.967.2751 (cell) or
DKrupa@the-APS.org.
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