Several news outlets have reported on findings that were discussed this past weekend at the American College of Cardiology Annual Conference, but I have not been able to track down the actual published research.  It may not be published yet. 

There were actually two stories making the headlines - one involves raisins and the other soy products.  Both are said to be associated with a lowering of blood pressure in the people studied.

The raisin research (for which I have no rich details) involved at least two groups of people.  One group had a snack of about a handful of raisins three times a day and the other group had a different snack, like cookies.  The results are that the raisin group lowered its blood pressure numbers and the mechanism is thought to be the potassium in the raisins.  Potassium has been found to lower blood pressure.
I want to look at the study to see 1) what else was going on 2) how much the blood pressure changed, and 3) if the snacks were equivalent calorie wise.  The raisins would have about 85 calories times 3 servings.  Over 250 calories of snack food every day.  Raisins are not a low energy dense food so those 85 calories are not that many raisins.

Just some things to think about - perhaps another place to get potassium is in bell peppers!