Colonic Availability of Bilberry Anthocyanins in Humans

Anthocyanins comprise a group of flavonoids and are important pigments in various plant species responsible for the distinctive colours of many flowers, fruits and vegetables. Dietary anthocyanins also receive considerable interest for their presumed roles in the prevention of various degenerative diseases. The aim of this study was to determine the amounts of anthocyanins reaching the colon after oral intake of bilberries (Vaccinium myrtillus L.), which were found to contain very high levels of anthocyanins (7834 mg/kg, compared to 365 mg/kg in cultivated blueberries according to quantitative analyses with authentic standards). After a polyphenol-free diet five healthy ileostomy volunteers each ate 300 g of bilberries. Ileostomy effluent was subsequently collected and anthocyanins in it were identified and quantified by HPLC-electrospray ionization tandem mass spectrometry and HPLC-diode array detection. In total, 46% ± 15% of the consumed anthocyanins were detected in the ileostomy effluent, with excretion peaking between one and four hours after intake. The results show that most of the bilberry anthocyanins were recovered in the ileostomy effluent, which would reach the colon under standard physiological circumstances and contribute to the prevention of inflammatory bowel diseases and malignant gastrointestinal diseases.