Study leader Dr. Janet Novotny of the U.S. Department of Agriculture in Beltsville, Md., and colleagues, had 56 study participants drink either a glass of low-calorie cranberry juice or low-calorie sweetened placebo drink for breakfast and dinner for eight weeks as part of a controlled diet, Medpagetoday.com reported.
Blood pressure was measured at the beginning, mid-point and end of the study, Novotny said.
The study found after eight weeks, blood pressure levels dropped from an average of 121/73 mmHg to 118/70 mmHg for those drinking the low-calorie cranberry juice. The placebo group showed no change, the study said.
Cranberry juice is rich in antioxidants -- naturally occurring molecules in fruit, tea, wine and other foods -- which have been associated with lower blood pressure in other studies, Novotny said.
However, since cranberry juice is tart, it is often sweetened, and Novotny suggested drinking the low-calorie juice or subtract something from the diet so the extra calories don't add weight.
The findings were presented at the American Heart Association's High Blood Pressure Research Scientific Sessions in Washington.