Across 37 studies spanning a decade of research, scientists have found that the polyphenols in grapes and blueberries offer modest but real encouragement for cardiovascular health — nudging blood vessel function and blood pressure in favorable directions. Yet the story carries a familiar tension in nutritional science: what works in concentrated extracts and short trials does not always translate to the plate, and no study has yet confirmed whether eating these fruits prevents actual heart attacks or strokes. The findings invite cautious optimism rather than prescription, reminding us that bio