The researchers found men with hypertension who drank Concord grape juice for 12 weeks had a significant reduction in both their systolic and diastolic blood pressure.
Researchers studied 80 healthy men, aged 45 to 70, for 12 weeks. Half the men drank an average of 12 ounces of grape juice a day and the other half drank the same amount of a placebo that looked and tasted like grape juice.
At the end of the 12 weeks, the 19 men who drank the grape juice had a drop from an average baseline systolic blood pressure of 142.7 mm Hg, to 137.0, and a drop in diastolic blood pressure from 87.9, to 82.1 mm Hg. The men who drank the placebo showed no change.
The study, by Radiant Research in Chicago, was funded by Welch Foods Inc. and presented at this week's Experimental Biology meeting in San Diego.
It's estimated that lowering systolic blood pressure by five points would result in a 14 percent reduction in deaths from stroke and a 9 percent reduction in deaths from heart disease, says the U.S. National High Blood Pressure Education Program.
Two previous clinical studies found Concord grape juice improved arterial wall flexibility, something that may help reduce blood pressure. Recent research also found that purple grape juice may inhibit the tendency of blood to clot and slow the oxidization of LDL (bad) cholesterol.
Here's where you can learn more about high blood pressure.