Posted on Oct 10, 2013, 6 a.m.
Flavonoids in blueberries may improve flow mediated dilation – a marker of blood vessel elasticity, among healthy men.
Blueberries are an abundant source of flavonoids – antioxidant compounds that occur in plants. Jeremy Spencer, from the University of Reading (United Kingdom), and colleagues conducted two double-blind crossover trials involving 21 healthy men. The first study assessed the effect of 4 different doses of blueberry flavonoids on flow mediated dilation (FMD) – a marker of blood vessel elasticity, at 5 different timepoints. The team observed that FMD increased at 1-2 hours post-consumption, and again at 6 hours post-consumption. The researchers then investigated the effects of 5 different doses of blueberry polyphenols between timepoint 0 and one hour later. They observed a dose-dependent response for consumptions up to 766 total blueberry polyphenols, after which the response reached a plateau. Positing that the increases in flow-mediated dilation observed decreased the activity of nicotinamide-adenine dinucleotide phosphate (NADPH) – an enzyme involved in the production of free radicals, the study authors submit that: “Blueberry intake acutely improves vascular function in healthy men in a time- and intake-dependent manner.”
Rodriguez-Mateos A, Rendeiro C, Bergillos-Meca T, Tabatabaee S, George TW, Heiss C, Spencer JP. “Intake and time dependence of blueberry flavonoid-induced improvements in vascular function: a randomized, controlled, double-blind, crossover intervention study with mechanistic insights into biological activity.” Am J Clin Nutr. 2013 Sep 4.