As one of the few fruits native to North America, blueberries have been enjoyed by Native Americans for hundreds of years. They have also enjoyed great popularity around the world in cuisines from Asia to the Mediterranean.
In terms of U.S. fruit consumption, blueberries rank only second to strawberries in popularity of berries. Blueberries are not only popular, but also repeatedly ranked in the U.S. diet as having one of the highest antioxidant capacities among all fruits, vegetables, spices and seasonings.
Research shows they can reduce both systolic and diastolic blood pressure and potentially better than pharmaceuticals.В The blood pressure relief comes from pterostilbene, a compound found in both grapes and blueberries. This antioxidant is chemically related to reservatrol, another heart-healthy compound that is found in the skin of grapes. Various studies have shown pterostilbene to have possible anti-cancer and anti-diabetes properties.
A growing body of research is also establishing blueberries as a potential ally to protect against diseases such heart disease and AlzheimerвЂ™s вЂ” so itвЂ™s no surprise that more and more people are picking blueberries than ever before!
вЂњThis tells us that blueberries may improve the health of blood vessels in addition to reducing blood pressure,вЂќ said Sarah Johnson, a nutrition and exercise researcher at Florida State University in Tallahassee who led the study.
Johnson and her coauthors do not suggest that blueberries should replace hypertension medications. But they say the berries might help offset a tendency toward rising blood pressure and stiffening blood vessels after menopause that raises womenвЂ™s heart disease risk.
Past research has suggested that blueberries may help lower blood pressure, the authors write in the Journal of the Academy of Nutrition and Dietetics. Some studies have also indicated that the flavonoids and other healthy plant compounds in blueberries may help to boost nitric oxide, a chemical that affects the cells that line blood vessel walls.
The Florida State researchers recruited 48 women to participate in their eight-week, randomized, double-blind, placebo-controlled clinical trial. Participants were randomly assigned to receive either 22 grams per day of freeze-dried blueberry powder or 22 grams of a control powder for eight weeks. This dose was equivalent to one cup of fresh blueberries.
The data showed that the blueberry powder was associated with significant reductions in systolic and diastolic blood pressure.
вЂњThe changes in blood pressure noted in this study are of clinical significance as they demonstrate that blood pressure can be favorably altered by the addition of a single dietary component (e.g. blueberries),вЂќ said lead author Sarah Johnson, PhD.
In addition, improvements in brachial-ankle pulse wave velocity were also reported. Pulse wave velocity is a non-invasive method for assessing arterial stiffness and has been shown to predict future cardiovascular events. In the current study, brachial ankle pulse wave velocity (baPWV), which is a composite measure of central (aortic) and peripheral arterial stiffness, was significantly reduced after eight weeks in the blueberry-treated group, whereas there were no changes in the control group.
On the other hand, carotid-femoral pulse wave velocity (cfPWV), the best measure of aortic stiffness, did not change in either group. This suggests that peripheral arteries may be more responsive to dietary interventions than central arteries.
вЂњThis [study] suggests that regular consumption of blueberries over the long term could potentially delay the progression of hypertension and reduce cardiovascular risk in postmenopausal women,вЂќ concluded the researchers.
The study was supported by the US Highbush Blueberry Council and the US Department of Agriculture.