By Michael Smith, North American Correspondent, MedPage Today
Published: August 27, 2009
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planne
Kudzu is a nuisance in the garden but might be a boon to the diet.
In rats, an extract from the root of the runaway vine lowered blood pressure, cholesterol, and other markers of metabolic disorders, according to J. Michael Wyss, PhD, of the University of Alabama Birmingham, and colleagues.
The findings suggest that kudzu extracts in humans might complement other strategies to reduce metabolic disorders, the researchers concluded online in the Journal of Agricultural and Food Chemistry.
Kudzu, introduced to the U.S. from Japan, was long promoted as an erosion fighter. But in the South, where the climate is ideal for it, kudzu soon grew out of control, and in 1953 the U.S. Department of Agriculture officially named it a pest weed.
Extracts of the root, a part of traditional medicine in China, have recently become available in the U.S., Wyss and colleagues said.
Among the extract’s components that might affect blood pressure and other conditions are a range of isoflavone glucosides, including puerarin, daidzin, and daidzein.
For this study, the researchers tested a commercially available extract on female, stroke-prone spontaneously hypertensive rats.
Half of the 28 animals had their ovaries removed before the experiments began, since there is some evidence that estrogen pathways play a role in the antihypertensive effects of some of the tested compounds.
The rats were divided into two groups — one fed a control diet and the other the same diet with the addition of 0.2% kudzu root extract. Within each diet group, half of the animals had intact ovaries and half did not.
After two months, the researchers said, rats getting the supplement had significantly lower arterial blood pressure (11 to 15 millimeters of mercury), plasma cholesterol, fasting blood glucose (between 20 and 30% lower), and fasting plasma insulin.
The reductions — all significant at P<0.05 -- were found in both the ovariectomized and intact animals, the researchers said.
Although the animals on the kudzu diet ate the same amount as their littermates, they gained significantly less weight during the experiments (at P<0.05), the researchers found. There was no apparent effect on their health, and no signs of toxicity or adverse events, they said.
Researchers said the exact mechanism is still unclear, but the results “suggest that incorporation of kudzu root supplements into a diet modulates glucose, lipids, and blood pressure.”
The study was supported by the NIH. The researchers did not report any conflicts.
Peng N, et al “Chronic dietary kudzu isoflavones improve components of metabolic syndrome in stroke-prone spontaneously hypertensive rats” J Agric Food Chem 2009; 57: 7268–73.