Chocolate intake increases urinary excretion of polyphenol-derived phenolic acids in healthy human subjects.
BACKGROUND
Proanthocyanidins, the most abundant polyphenols in chocolate, are not depolymerized in the stomach and reach the small intestine intact, where they are hardly absorbed because of their high molecular weight. In vitro and in vivo studies using pure compounds as substrates suggest that proanthocyanidins and the related catechin monomers may be degraded into more bioavailable low-molecular-weight phenolic acids by the microflora in the colon.


OBJECTIVE
The aim of the study was to estimate the amounts of phenolic acids formed by the microflora and excreted in the urine of human subjects after consumption of polyphenol-rich chocolate.


METHODS
After consumption of a polyphenol-free diet for 2 d and a subsequent overnight fast, 11 healthy subjects (7 men and 4 women) consumed 80 g chocolate containing 439 mg proanthocyanidins and 147 mg catechin monomers. All urine was collected during the 24 h before chocolate consumption and at 3, 6, 9, 24, and 48 h after chocolate consumption. Aromatic acids were identified in urine by gas chromatography-mass spectrometry and were quantified by HPLC-electrospray ionization tandem mass spectrometry.


RESULTS
Chocolate intake increased the urinary excretion of the 6 following phenolic acids: m-hydroxyphenylpropionic acid, ferulic acid, 3,4-dihydroxyphenylacetic acid, m-hydroxyphenylacetic acid, vanillic acid, and m-hydroxybenzoic acid.


CONCLUSIONS
The antioxidant and biological effects of chocolate may be explained not solely by the established absorption of catechin monomers but also by the absorption of microbial phenolic acid metabolites.
Rios
Laurent Y
LY
Laboratoire des Maladies Métaboliques et Micronutriments, INRA, Saint-Genès-Champanelle, France.
Gonthier
Marie-Paule
MP
Rémésy
Christian
C
Mila
Isabelle
I
Lapierre
Catherine
C
Lazarus
Sheryl A
SA
Williamson
Gary
G
Scalbert
Augustin
A
D015102:3,4-Dihydroxyphenylacetic Acid / Q000652:urine; D000328:Adult; D002099:Cacao / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003373:Coumaric Acids / Q000652:urine; D005260:Female; D005419:Flavonoids; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D062385:Hydroxybenzoates / Q000652:urine*; D007700:Kinetics; D008297:Male; D010636:Phenols / Q000008:administration & dosage* / Q000032:analysis; D011108:Polymers / Q000008:administration & dosage* / Q000032:analysis; D059808:Polyphenols; D021241:Spectrometry, Mass, Electrospray Ionization; D014641:Vanillic Acid / Q000652:urine
D003373:Coumaric Acids; D005419:Flavonoids; D062385:Hydroxybenzoates; D010636:Phenols; D011108:Polymers; D059808:Polyphenols; D015102:3,4-Dihydroxyphenylacetic Acid; C038547:dihydro-3-coumaric acid; C004999:ferulic acid; D014641:Vanillic Acid; C017616:phenolic acid