Anthocyanins are the most common polyphenols in berries and red wine, along with other flavonoids, phenolic acids, minerals and vitamins. Anthocyanins are extensively metabolized and they are transformed into glucuronides and phenolic acids. The investigators have recently shown that the acute consumption of blueberries leads to an increase in endothelium-dependent vasodilation measured as flow-mediated dilatation (FMD) in young male volunteers. There were significant correlations of these effects with the plasma concentration of phenolic acids and anthocyanin metabolites. Therefore, the present study aims at understanding to which extent the anthocyanins contained in berries are related with positive effects in endothelial function. A large part of the absorbed anthocyanin circulate in the blood in as methyl, glucuronyl and sulfate metabolites, as well as phenolic acids. The formation of these metabolites begins right as early as 2h after consumption due to metabolism at the small intestine and a second plasmatic peak occurs around 6h due the metabolism of colonic bacteria. Whether and which metabolites are associated with biological effects and the mechanisms underlying this effect remains unclear.

Inclusion Criteria:

• Post-menopausal female subjects without clinical signs or symptoms of cardiovascular disease, no menstruation cycle for more than 1 year, postmenopausal status conformed by female hormone analysis
• > 50 years

Exclusion Criteria:

• cardiovascular disease
• acute inflammation
• cardiac arrhythmia
• renal failure
• heart failure (NYHA II-IV)
• diabetes mellitus
• C-reactive protein > 0.5 mg/dL
• malignant disease
• hypotension (≤100 / 60 mm Hg)