Having one cup of blueberries daily could help reduce blood pressure and arterial stiffness, both of which are linked to heart disease, according to scientists from the Florida State University.
During the eight-week study period, 48 postmenopausal women with pre- and stage-1 hypertension were randomly assigned to receive either 22 grams of freeze-dried blueberry powder, equivalent to one cup of fresh blueberries, or 22 grams of a placebo powder along with their normal diet and exercise routines. The participants' blood pressure, arterial stiffness and select blood biomarkers were recorded at the beginning and post the 8-week study period.
It was found that participants who received the blueberry powder on average had a 7 mmHg (5.1 percent) decrease in systolic blood pressure that measures the pressure in the arteries when the heart beats, and a 5 mmHg (6.3 percent) reduction in diastolic blood pressure that measures the pressure in the arteries between heartbeats. Also, participants in the blueberry-treated group had an average reduction of 97 cm/second (6.5 percent) in arterial stiffness. Researchers also noticed that nitric oxide, a blood biomarker known to be involved in the widening of blood vessels, increased by 68.5 percent.
Researcher Sarah A. Johnson said, "Our findings suggested regular consumption of blueberries could potentially delay the progression of pre-hypertension to hypertension, therefore reducing cardiovascular disease risk. Arterial stiffness and the narrowing of blood vessels are both a part of hypertension. The rise in nitric oxide helps explain the reductions in blood pressure."
The study is published in the Journal of the Academy of Nutrition and Dietetics.