There is trial data indicating blueberries help reduce both systolic and diastolic blood pressure.
This double-blind, placebo controlled trial assigned 48 women to receive either 22 grams of freeze-dried blueberry powder or 22 grams of a control powder daily for 8-weeks. Results indicate that blueberry consumption may reduce blood pressure and arterial stiffness.
These improvements may be linked to enhanced nitric oxide mediated vasodilation. Vasodilation refers to the widening of blood vessels, which in turn lowers blood pressure because the heart then exerts less force against arterial walls as it circulates blood.
At the conclusion of the study, participants consuming the blueberry powder daily on average reduced systolic blood pressure 5.1% and diastolic blood pressure was lowered on average 6.3%.
Twenty-two grams of freeze-dried blueberry powder is equal to about 1 cup of fresh blueberries daily.