Scientists from the University of Düsseldorf have found that eating cranberries every day may improve blood vessel function and support heart health.
Cranberries, an evergreen shrub native to wet regions of the Northeastern and North Central United States, have a long history of medicinal use.
Traditionally, cranberry fruits and leaves were used to treat bladder, stomach, and liver conditions, as well as diabetes, wounds, and other ailments. Today, cranberries are best known for their role in preventing urinary tract infections (UTIs).
Cranberries are exceptionally rich in polyphenols—plant compounds linked to numerous health benefits.
They contain high levels of flavan-3-ols, anthocyanins, and flavonols, and provide more polyphenols per serving (373 mg per 50 g) than apples, cherries, blueberries, blackberries, grapes, or strawberries.
Previous studies have suggested that cranberry juice may support heart health by improving cholesterol levels, lowering blood pressure, and reducing arterial stiffness due to its anthocyanin content.
However, it has been unclear whether eating whole cranberries daily would offer sustained cardiovascular benefits, especially in healthy individuals. To examine this, researchers tested the effects of daily consumption of freeze-dried whole cranberry powder in 45 healthy men.
Participants consumed either 9 g of cranberry powder dissolved in water (equivalent to 100 g of fresh cranberries) or a control powder for one month.
The researchers measured several markers of blood vessel and heart health—including blood pressure, heart rate, blood lipids, and blood glucose—at baseline, two hours after the first dose, and after one month. They found that cranberry consumption significantly improved blood vessel function both two hours after intake and after one month of daily use.
In addition, cranberry polyphenol metabolites were detected in the participants’ blood and urine. Further analysis identified specific metabolites, such as cinnamic acid-4′-glucuronide, 4-hydroxybenzoic acid-3-sulfate, and 2,5-dihydroxybenzoic acid, that were associated with improved vascular function shortly after consumption. Other metabolites, including 3′-hydroxycinnamic acid and 4-methoxycinnamic acid-3′-glucuronide, were linked to longer-term improvements in blood vessel health after one month of daily intake.
Based on these findings, the researchers suggest that eating whole cranberry powder daily can provide both immediate and sustained benefits to blood vessel function in healthy men. These improvements appear to be closely linked to measurable levels of cranberry-derived metabolites in the bloodstream.
The study does have limitations. It included only young, healthy men, which means the results may not apply to women, older adults, or people at increased risk of heart disease. Additionally, the intervention lasted only one month, so the long-term effects of daily cranberry consumption remain uncertain. Further research is needed to explore these questions.
The study was conducted by Ana Rodriguez-Mateos and colleagues and published in Food & Function.
