title: Polyphenols from alcoholic apple cider are absorbed, metabolized and excreted by humans.
abstract: We determined the uptake and excretion of low doses of polyphenols in six subjects who each consumed 1.1 L of an alcoholic cider beverage. Over a 24-h period, no phloretin was detected in plasma (detection limit = 0.036 micromol/L), but 21 +/- 5% of the dose (4.8 mg) was excreted in the urine. In contrast, from a low dose of 1.6-mg quercetin equivalents, no quercetin was found in urine or plasma, but 3'-methyl quercetin was detected in plasma [C(max) (maximum concentration) = 0.14 +/- 0.19 micromol/L; range: 0 to 0.44 micromol/L]. No flavanol monomers (dose of free (+)-catechin and (-)-epicatechin = 3.5 mg) were detected in urine or plasma (detection limit: 0.01 micromol/L). Caffeic acid (total dose including esters = 11 mg) was detected only in plasma within 2 h, with C(max) = 0.43 +/- 0.3 micromol/L (range: 0.18 to 0.84 micromol/L). An almost 3-fold increase in hippuric acid was detected in 24-h urine (74 +/- 29 micromol/L; range: 38-116 micromol/L), compared with a prestudy value of 19 +/- 9 micromol/L. These data show that polyphenols are taken up from cider, that phloretin is excreted in the urine and suggest that low doses of quercetin are extensively methylated in humans.
authors.affiliation: Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA United Kingdom.
authors.forename: M Susan
authors.initials: MS
authors.lastname: DuPont
authors.forename: Richard N
authors.initials: RN
authors.lastname: Bennett
authors.forename: Fred A
authors.initials: FA
authors.lastname: Mellon
authors.forename: Gary
authors.initials: G
authors.lastname: Williamson
mesh_terms: D000042:Absorption; D000328:Adult; D000434:Alcoholic Beverages; D002109:Caffeic Acids / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005419:Flavonoids; D006626:Hippurates / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D006801:Humans; D008297:Male; D027845:Malus / Q000737:chemistry; D008745:Methylation; D010636:Phenols / Q000097:blood / Q000378:metabolism* / Q000652:urine; D010693:Phloretin / Q000097:blood / Q000652:urine; D011108:Polymers / Q000378:metabolism*; D011794:Quercetin / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine
chemical_list: D002109:Caffeic Acids; D005419:Flavonoids; D006626:Hippurates; D010636:Phenols; D011108:Polymers; D011794:Quercetin; D010693:Phloretin; C030514:hippuric acid; C040048:caffeic acid