Blueberries Shown to Pack Big Heart Health Benefits

“Our findings suggest that regular consumption of blueberries could potentially delay the progression of prehypertension to hypertension, therefore reducing cardiovascular disease risk,” said Dr. Sarah A. Johnson, assistant director of the Center for Advancing Exercise and Nutrition Research on Aging (CAENRA), and postdoctoral fellow in the department of nutrition, food and exercise sciences at Florida State University (FSU; Tallahassee, USA).

Dr. Johnson and nutrition and exercise scientists colleagues at FSU are the authors of a new study, which was published online January 7, 2015, in the Journal of the Academy of Nutrition and Dietetics. Dr. Johnson stated she is interested in looking at how functional foods—foodstuffs that have a positive impact on health beyond essential nutrition—can prevent and reverse negative health outcomes, especially for postmenopausal women. “Cardiovascular disease is the leading cause of death in the United States,” she said. “Once women go through menopause, this puts them at an even greater risk for it. Our findings suggest that the addition of a single food, blueberries, to the diet may mitigate the negative cardiovascular effects that often occur as a result of menopause.”

Over an eight-week period, 48 postmenopausal women with pre- and stage-1 hypertension were randomly assigned to receive either 22 g of freeze-dried blueberry powder (one cup of fresh blueberries) or 22 g of a placebo powder. In the meantime, participants kept on their normal diet and exercise routines.

At the start of the study, the team took participants’ blood pressure and measured their arterial stiffness and specific blood biomarkers. At the end of the eight weeks, participants receiving the blueberry powder on average had a 7 mmHg (5.1%) decrease in systolic blood pressure, which is the top number in the blood pressure reading that measures the pressure in the arteries when the heart beats. They also saw a 5 mmHg (6.3%) reduction in diastolic blood pressure, or the bottom number measuring the pressure in the arteries between heartbeats. Moreover, study participants in the blueberry-treated group had an average reduction of 97 cm/second (6.5%) in arterial stiffness.

The investigators also discovered that nitric oxide, a blood biomarker known to be involved in the widening of blood vessels, increased by 68.5%. That is important, according to Dr. Johnson, because arterial stiffness and the narrowing of blood vessels are both a part of hypertension. This rise in nitric oxide helps explain the reductions in blood pressure.

Earlier research on blueberries have shown positive effects on cardiovascular risk factors including blood pressure, but they all included large amounts of blueberry powder consumption, anywhere from 50–250 g. In the case of 250 g, that would mean more than 11 cups of fresh blueberries, which may not be realistic for individuals to eat on a regular basis.

Dr. Johnson reported that future studies will consider other dosages of blueberries, longer intervention periods, and other sample populations.

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