The Effects of Orange Polyphenols on Vascular and Cognitive Function

Abstract

IntroductionEvidence suggests that polyphenols may beneficially influence vascular function and neurocognition. The aims of the current research was to determine the pharmacokinetics of the major polyphenols in oranges and to determine whether orange beverages, with different levels of polyphenols, can modulate vascular and cognitive function.MethodsIn men (n=6) we measured the maximum plasma concentration (Cmax) and time to reach maximum concentration (Tmax) of hesperetin and naringenin following consumption of 3 different orange beverages. Subsequently we assessed flow mediated dilatation (FMD) at baseline and at 2, 5 and 7 hours in a randomized, double blind, cross over study in males with moderately raised lipids or BMI (n=37) following one of 4 treatments; water with sugar control (WSC), orange juice without pulp (OJWP), processed whole orange (PWO) or whole orange (WO). We also assessed cognitive performance at baseline and 2 and 5 hours following consumption of either the WSC or PWO.ResultsThe Cmax of hesperetin and naringenin were 0.25µm and 0.09µm respectively and the Tmax 6.8h and 6.7h. Compared to the control OJWP, PWO and WO attenuated a meal induced decrease in FMD (fig. 1). PWO attenuated a decline in subjective alertness, improved speed of processing and overall cognitive performance.imageConclusionThe effects on vascular and cognitive function correlated with the peak plasma concentration of flavonoid metabolites. The effects on cognition are likely due to changes in blood flow and improved delivery of metabolic substrates to neural tissue.These results suggest that polyphenol rich orange products can modify a biomarker associated with a reduced risk of cardiovascular disease and beneficially influence neurocognition.