A daily intake of one cup of blueberries will reduce blood pressure and arterial stiffness, which decreases heart disease risk.
The effect of lowering blood pressure and arterial stiffness may be due to a rise in nitric oxide production in the blood vessels.
Blueberries are a rich source of flavonoids such as anthocyanin, a natural compound that acts as an antioxidant.
Flavonoids have an anti-inflammatory effect as well as increasing the production of nitric oxide in the body.
Nitric oxide can make the inner muscles of the blood vessels relax and so they widen and circulation improves.
By increasing blood flow through the body, blood pressure will consequently go down.
In the study, a group of subjects were fed an equivalent of one cup of blueberries per day for 8 weeks to see if they had any effect on lowering blood pressure.
There were no other changes in these participants’ normal diet and routines.
After 8 weeks, there was a reduction of 7 mm/Hg in their systolic blood pressure and 5 mm/Hg reduction in their diastolic blood pressure.
Systolic blood pressure is the top number of the blood pressure reading, which is the pressure when the heart beats.
Diastolic blood pressure is the bottom number, which is the pressure when the heart rests between beats.
In addition, arterial stiffness was reduced by 6.5 percent in participants who were in the blueberry-treated group.
The study shows that the nitric oxide level in these people was increased by 68.5 percent, which explains the declines in blood pressure.
Dr Sarah A. Johnson, the study’s first author, said:
“Our findings suggest that regular consumption of blueberries could potentially delay the progression of prehypertension to hypertension, therefore reducing cardiovascular disease risk.”
“Cardiovascular disease is the leading cause of death in the United States.
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.”
The study was published in the Journal of the Academy of Nutrition and Dietetics (Johnson et al., 2015).