Anthocyanins are a subclass of (poly)phenols very abundant in berries and red grapes. Increasing evidence from human epidemiological and dietary intervention studies suggests that anthocyanins may have cardiovascular health benefits. A double blind randomized controlled crossover, dose-response study will be conducted in 10 young healthy men. On 6 different days, subjects will consume capsules containing 0, 80, 160, 240, 320 and 480 mg of purified anthocyanins with a one-week wash-out period. Flow-mediated dilation (FMD) and blood pressure will be measured at baseline and at 2 and 6 h after consumption. Blood samples will also be taken and quantification of plasma anthocyanin metabolites using UPLC-Q-TOF-MS will be performed. The aim is to investigate whether purified anthocyanins are able to increase FMD at 2h and 6h post consumption and whether these effects correlate with anthocyanin- derived phenolic acids quantified in the plasma.