Menopausal women are at a comparatively high risk for memory loss, high blood pressure and diabetes. The standard treatment for these problems, a decade ago, was long-term hormone replacement therapy (HRT). But studies have shown that widespread use of HRT is associated with significant adverse effects.
As a result, certain alternatives have been sought through several studies.
One research lab investigating through several studies has found that grape, soy and kudzu, which are dietary polyphenols, can have some beneficial effects similar to HRT but without the substantial adverse effects.
These and related studies are being led by physiologist J. Michael Wyss, Department of Cell Biology, University of Alabama at Birmingham (UAB), Birmingham.
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 supposition that grape seed polyphenols reduced salt-sensitive hypertension in young, estrogen-depleted rats. After ten weeks on specific diets, grape seed supplementation considerably reduced arterial pressure in the rats fed a high salt diet, compared to controls. The results signify that grape seed polyphenols reduce arterial pressure in rats, probably via an antioxidant mechanism.
In a second test, the team found that the removal of soy polyphenols from the diet of estrogen depleted rats, 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.
In the third test, the UAB researchers 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.
These studies reveal that three polyphenols, grape, soy and kudzu, blunt hypertension, insulin resistance and cognitive decline when estrogen is not present in female rats.
"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," says Dr. Wyss.