title: Effect of milk on the urinary excretion of microbial phenolic acids after cocoa powder consumption in humans.
abstract: Health effects of cocoa flavonols depend on their bioavailability, which is strongly influenced by the food matrix and the degree of flavanol polymerization. The effect of milk on the bioavailability of cocoa flavanoids considering phase II metabolites of epicatechin has been the subject of considerable debate. This work studies the effect of milk at the colonic microbial metabolism level of the nonabsorbed flavanol fraction that reaches the colon and is metabolized by the colonic microbiota into various phenolic acids. Twenty-one human volunteers followed a diet low in polyphenols for at least 48 h before taking, in a random order, 40 g of cocoa powder dissolved either in 250 mL of whole milk or in 250 mL of water. Urine samples were collected before the intake and during three different periods (0-6, 6-12, and 12-24 h). Phenolic acids were analyzed by LC-MS/MS after solid-phase extraction. Of the 15 metabolites assessed, the excretion of 9 phenolic acids was affected by the intake of milk. The urinary concentration of 3,4-dihydroxyphenylacetic, protocatechuic, 4-hydroxybenzoic, 4-hydroxyhippuric, hippuric, caffeic, and ferulic acids diminished after the intake of cocoa with milk, whereas urinary concentrations of vanillic and phenylacetic acids increased. In conclusion, milk partially affects the formation of microbial phenolic acids derived from the colonic degradation of procyanidins and other compounds present in cocoa powder.
authors.affiliation: Nutrition and Food Science Department, XaRTA, INSA, Pharmacy Faculty, University of Barcelona, Barcelona, Spain.
authors.forename: Mireia
authors.initials: M
authors.lastname: Urpi-Sarda
authors.forename: Rafael
authors.initials: R
authors.lastname: Llorach
authors.forename: Nasiruddin
authors.initials: N
authors.lastname: Khan
authors.forename: Maria
authors.initials: M
authors.lastname: Monagas
authors.forename: Maria
authors.initials: M
authors.lastname: Rotches-Ribalta
authors.forename: Rosa
authors.initials: R
authors.lastname: Lamuela-Raventos
authors.forename: Ramon
authors.initials: R
authors.lastname: Estruch
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Tinahones
authors.forename: Cristina
authors.initials: C
authors.lastname: Andres-Lacueva
mesh_terms: D000818:Animals; D002099:Cacao; D006801:Humans; D062385:Hydroxybenzoates / Q000652:urine*; D008892:Milk
chemical_list: D062385:Hydroxybenzoates; C017616:phenolic acid