J Nutr. 2012 Sep;142(9):1626-32.
Grape polyphenols reduce blood pressure and increase flow-mediated vasodilation in men with metabolic syndrome.
Barona J, Aristizabal JC, Blesso CN, Volek JS, Fernandez ML.
Source
Department of Nutritional Sciences, University of Connecticut, Storrs, CT, USA.
Abstract
We evaluated the effects of grape polyphenols in individuals classified with
metabolic syndrome (MetS). Men (n = 24) aged 30-70 y were randomly assigned to
consume either a freeze-dried grape polyphenol powder (GRAPE) or a placebo for
30 d in a double-blind, crossover design, separated by a 3-wk washout period.
Participants were asked to maintain their usual diet and physical activity
during the study and abstain from consuming polyphenol-rich foods. MetS criteria
including blood pressure (BP) and markers of vascular endothelial function
including brachial artery flow-mediated vasodilation (FMD), plasma total nitrite
+ nitrate (NOx) to estimate NO production, plasma soluble intercellular adhesion
molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1)
were measured at the end of each dietary period. Systolic BP (P < 0.0025) and
plasma sICAM-1 concentrations (P < 0.025) were lower, whereas the FMD response
was higher (P < 0.0001), during the GRAPE compared with the placebo period. In
addition, changes in sVCAM-1 concentrations between periods were positively
correlated with changes in systolic BP (r = 0.45; P < 0.05). Although NOx
concentrations did not differ between periods, changes in systolic BP were
negatively correlated with changes in NOx concentrations (r = -0.44; P < 0.05),
indicating the vasodilating properties of NO. Other MetS variables did not
differ between the GRAPE and placebo periods. These results suggest that GRAPE
polyphenols may potentiate vasorelaxation and reduce BP and circulating cell
adhesion molecules, resulting in improvements in vascular function.
PMID: 22810991 [PubMed - indexed for MEDLINE]