Maybe. A study in The Journal of the Academy of Nutrition and Dietetics found that those people in the study, (women ages 45 to 65 with high blood pressure) saw an average 5.1% decrease in systolic blood pressure (the top number) and a 6.3% decrease in diastolic pressure. Half ate 22 grams of freeze-dried blueberry powder (equivalent to a cup of blueberries) daily for 8 weeks. The others consumed an identical-looking and tasting placebo. Levels of nitric oxide, known to be involved in relaxing and widening blood vessels increased significantly in the blueberry eaters. There were no significant changes in the placebo group.
The scientists write that the improvement was moderate compared with that of blood pressure medicines. But, they say, eating blueberries in larger amounts or for longer periods could increase the effect.
Sarah A. Johnson, the lead author, and a postdoctoral researcher at Florida State University said she saw no reason for people to radically change their diet, but that if they are not eating blueberries, they might want to try them. “There is something very special about the composition of blueberries that is responsible for their effect on blood pressure,” she said. Other fruits and plant extracts have not produced the same result.”