title: Milk decreases urinary excretion but not plasma pharmacokinetics of cocoa flavan-3-ol metabolites in humans.
abstract: BACKGROUND
  Cocoa drinks containing flavan-3-ols are associated with many health benefits, and conflicting evidence exists as to whether milk adversely affects the bioavailability of flavan-3-ols.
  
  
  OBJECTIVE
  The objective was to determine the effect of milk on the bioavailability of cocoa flavan-3-ol metabolites.
  
  
  METHODS
  Nine human volunteers followed a low-flavonoid diet for 2 d before drinking 250 mL of a cocoa beverage, made with water or milk, that contained 45 micromol (-)-epicatechin and (-)-catechin. Plasma and urine samples were collected for 24 h, and flavan-3-ol metabolites were analyzed by HPLC with photodiode array and mass spectrometric detection.
  
  
  RESULTS
  Milk affected neither gastric emptying nor the transit time through the small intestine. Two flavan-3-ol metabolites were detected in plasma and 4 in urine. Milk had only minor effects on the plasma pharmacokinetics of an (epi)catechin-O-sulfate and had no effect on an O-methyl-(epi)catechin-O-sulfate. However, milk significantly lowered the excretion of 4 urinary flavan-3-ol metabolites from 18.3% to 10.5% of the ingested dose (P = 0.016). Studies that showed protective effects of cocoa and those that showed no effect of milk on bioavailability used products that have a much higher flavan-3-ol content than does the commercial cocoa used in the present study.
  
  
  CONCLUSIONS
  Most studies of the protective effects of cocoa have used drinks with a very high flavan-3-ol content. Whether similar protective effects are associated with the consumption of many commercial chocolate and cocoa products containing substantially lower amounts of flavan-3-ols, especially when absorption at lower doses is obstructed by milk, remains to be determined.
authors.affiliation: Division of Ecology and Evolutionary Biology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
authors.forename: William
authors.initials: W
authors.lastname: Mullen
authors.forename: Gina
authors.initials: G
authors.lastname: Borges
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Donovan
authors.forename: Christine A
authors.initials: CA
authors.lastname: Edwards
authors.forename: Mauro
authors.initials: M
authors.lastname: Serafini
authors.forename: Michael E J
authors.initials: ME
authors.lastname: Lean
authors.forename: Alan
authors.initials: A
authors.lastname: Crozier
mesh_terms: D000082:Acetaminophen / Q000097:blood; D000818:Animals; D001628:Beverages; D001682:Biological Availability; D002099:Cacao; D002392:Catechin / Q000031:analogs & derivatives / Q000097:blood / Q000652:urine; D002417:Cattle; D005419:Flavonoids / Q000378:metabolism / Q000493:pharmacokinetics*; D005746:Gastric Emptying / Q000502:physiology*; D005772:Gastrointestinal Transit / Q000502:physiology*; D006801:Humans; D008892:Milk / Q000378:metabolism*; D010936:Plant Extracts / Q000493:pharmacokinetics*; D012639:Seeds; D013463:Sulfuric Acid Esters / Q000097:blood / Q000652:urine
chemical_list: D005419:Flavonoids; D010936:Plant Extracts; D013463:Sulfuric Acid Esters; C452422:epicatechin sulfate; C404987:flavan-3-ol; D000082:Acetaminophen; D002392:Catechin