Grape juice may lower BP by relaxing arteries
new studies presented at the Experimental Biology meeting this
A human trial on 40 Korean men with mild hypertension has shown that grape juice consumed for eight weeks caused a significant drop in blood pressure.
A new laboratory study presented this week appears to offer a mechanism for this effect. Researchers from the Louis Pasteur University in Strasbourg, France, led by Valerie Schini-Kerth, found that Concord grape juice produced arterial relaxation by increasing the activity of a nitric oxide synthase in cells lining the arterial wall.
John D. Folts, professor of medicine at the University of Wisconsin School of Medicine also presented research showing the lowering of blood pressure in a laboratory model, as well as the lowering of cholesterol and the inhibition of atherosclerosis, compared to a placebo group.
"Previous studies by my group have shown that Concord grape juice enables the brachial arteries to expand to accommodate increased blood flow. Likewise, other researchers have shown that nitric oxide production from platelets may well be the mechanism behind Concord grape juice's ability to reduce the tendency for the blood to clot," said Dr Folts.
He said the new results "add credence to the Korean study, suggesting that the Concord grape juice is functioning on a number of levels in the cardiovascular system".
"Nonetheless, we need to be cautious when interpreting preliminary data such as from the Korean study. For example, the placebo group also saw a small drop in blood pressure, although not a significant one, and while the Concord grape juice group's numbers were significant compared to baseline, they did not reach significance when compared group to group."
A larger trial will be necessary to confirm the blood pressure lowering effect, according to the researcher.
The US National High Blood Pressure Education Program estimates that lowering systolic blood pressure by five points would results in a 14 per cent drop in deaths from stroke, a 9 per cent drop in heart disease deaths, and a 7 per cent drop in overall mortality.
The Concord grape juice for these studies was provided by Welch Foods. The company also partially supported the lab research.