The study – published in the Journal of Nutrition – evaluates the effects of grape polyphenols in people with metabolic syndrome (MetS) – revealing that consumption of a freeze dried whole-grape powder led to reductions in blood pressure, improved blood flow and reduced inflammation.
Led by Dr Maria Luz Fernandez at the University of Connecticut, USA, the research team suggested that consumption of grapes may help protect heart health in people with metabolic syndrome by improving vascular functions.
Metabolic syndrome refers to a cluster of conditions including high blood pressure, raised blood sugar level, excess body fat around the waist or low HDL (the good cholesterol) and increased blood triglycerides – all of which are known to significantly increase the risk for heart disease, stroke and diabetes.
"These results suggest that consuming grapes can improve important risk factors associated with heart disease, in a population that is already at higher risk," said Fernandez.
"This further supports the accumulating evidence that grapes can positively influence heart health, and extends it to men with metabolic syndrome."
The randomized, placebo-controlled, crossover study, recruited 24 men between the age of 30 and 70 years – all of whom had metabolic syndrome.
The participants were randomly assigned to consume grapes, in the form of a freeze-dried whole grape powder, or a placebo powder, for four weeks. Following a three week washout period, individuals were then allocated to the alternate supplementation for a further four weeks.
Fernandez and her colleagues observed reductions in key risk factors for heart disease in men with metabolic syndrome when the grape powder was consumed, they said – revealing that blood pressure was lowered, while blood flow was improved and inflammation was reduced
They said the study findings suggest that grape polyphenols “may potentiate vasorelaxation and reduce blood pressure and circulating cell adhesion molecules, resulting in improvements in vascular function.”
Source: Journal of Nutrition
Published online ahead of print, doi: 10.3945/jn.112.162743
“Grape Polyphenols Reduce Blood Pressure and Increase Flow-Mediated Vasodilation in Men with Metabolic Syndrome”
Authors: Jacqueline Barona, Juan C. Aristizabal, Christopher N. Blesso, Jeff S. Volek, Maria Luz Fernandez