The health benefits of berries have been well documented, and cranberries are no exception.

Cranberry juice has long been used to maintain a clean urinary tract and healthy kidneys, but researchers from the University of Duesseldorf in Germany found that the tart, tasty beverage may also have a positive effect on the health of your heart. Results from the small study revealed a promising relationship between cranberry juice and improved heart function.

Researchers gave male subjects, ages 18-40, a little under two cups of sweetened cranberry juice from concentrate. The juice was prepared with water to concentrations ranging from 0 to 117 percent. Measurements such as blood pressure and arterial stiffness were taken at one, two, four, six and eight hours post-consumption.

Blood and urine samples were also collected for 24 hours following consumption to detect changes in plasma and urinary cranberry-derived polyphenols, which are micronutrients that play a role in the prevention of conditions such as cancer and cardiovascular disease. Participants showed improvement of vascular function across the board, even those given just 25 percent of concentrated cranberry, which is equivalent to cranberry juice cocktail. Participants who were given the highest concentration of cranberry juice also saw improvements in systolic blood pressure.

The researchers concluded that cranberry juice’s role in defending the circulatory system could help lower the risk of plaque buildup in the arteries. This suggests that cranberries play an important role in a heart-healthy diet.

The study was small so more research is needed to confirm how beneficial cranberries are to your health. Cranberries are often served with a side of sugar in juice drinks, so moderation is key if you are thinking of adding cranberry to your diet.