One cup of blueberries a day helps reduce risk of heart disease

Washington: Adding one cup of blueberries to your daily diet could help reduce blood pressure and arterial stiffness, both of which are linked to cardiovascular disease.

Sarah A. Johnson from Florida State University said that their findings suggested regular consumption of blueberries could potentially delay the progression of prehypertension to hypertension, therefore reducing cardiovascular disease risk.

Johnson, who wanted to look at how functional foods could prevent and reverse negative health outcomes, particularly for postmenopausal women, said that once women go through menopause, it puts them at an even greater risk for it. The 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 grams of freeze-dried blueberry powder-the equivalent to one cup of fresh blueberries-or 22 grams of a placebo powder. Participants, meanwhile, continued their normal diet and exercise routines.

At the beginning of the study, the team took participants' blood pressure and measured their arterial stiffness and select blood biomarkers.

At the end of the eight weeks, participants receiving the blueberry powder on average had a 7 mmHg (5.1 percent) 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 percent) reduction in diastolic blood pressure, or the bottom number measuring the pressure in the arteries between heartbeats.

Additionally, participants in the blueberry-treated group had an average reduction of 97 cm/second (6.5 percent) in arterial stiffness.

They also found that nitric oxide, a blood biomarker known to be involved in the widening of blood vessels, increased by 68.5 percent. That is important, Johnson said, 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.

The study appears in the Journal of the Academy of Nutrition and Dietetics.