"Can a cup of blueberries keep the doctor away Maybe. Researchers conducted a randomized doubleblind placebocontrolled study of  postmenopausal women ages  to  with high blood pressure. Half ate  grams of freezedried blueberry powder equivalent to a cup of blueberries daily for eight weeks. The others consumed an identicallooking and tasting placebo. The study in The Journal of the Academy of Nutrition and Dietetics https found that those who ate the blueberry preparation saw an average . percent decrease in systolic blood pressure the top number and a . percent decrease in diastolic pressure. 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 improvement the scientists write 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. The lead author Sarah A. Johnson https 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."