Chlorogenic acid and caffeic acid are absorbed in humans

Chlorogenic acid, an ester of caffeic acid and quinic acid, is a major phen olic compound in coffee; daily intake in coffee drinkers is 0.5-1 g. Chloro genic acid and caffeic acid are antioxidants in vitro and might therefore c ontribute to the prevention of cardiovascular disease. However, data on the absorption of chlorogenic acid and caffeic acid in humans are lacking. We determined the absorption of chlorogenic acid and caffeic acid in a cross-o ver study with 4 female and 3 male healthy ileostomy subjects. In such subj ects, degradation by the colonic microflora is minimal and absorption can b e calculated as the amount ingested minus the amount excreted in ileostomy effluent. The ileostomy subjects ingested 2.8 mmol chlorogenic acid and 2.8 mmol caffeic acid on separate days in random order and subsequently collec ted ileostomy fluid and urine for 24 h. Absorption of chlorogenic acid was 33 +/- 17% (mean +/- SD) and of caffeic acid 95 +/- 4%. Traces of the inges ted chlorogenic acid and 11% of the ingested caffeic acid were excreted in urine. Thus, one third of chlorogenic acid and almost all of the caffeic ac id were absorbed in the small intestine of humans. This implies that part o f chlorogenic acid from foods will enter into the blood circulation, but mo st will reach the colon.