Absorption, metabolism, and excretion of green tea flavan-3-ols in humans with an ileostomy

Angélique Stalmach, William Mullen, Heike Steiling, Gary Williamson, Michael E J Lean, Alan Crozier

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133 Citations (Scopus)

Abstract

Green tea containing 634 mmol of flavan-3-ols was ingested by human subjects with an ileostomy. Ileal fluid, plasma, and urine collected 0-24 h after ingestion were analysed by HPLC-MS. The ileal fluid contained 70% of the ingested flavan-3-ols in the form of parent compounds (33%) and 23 metabolites (37%). The main metabolites effluxed back into the lumen of the small intestine were O-linked sulphates and methyl-sulphates of (epi)catechin and (epi)gallocatechin. Thus, in subjects with a functioning colon substantial quantities of flavan-3-ols would pass from the small to the large intestine. Plasma contained 16 metabolites, principally methylated, sulphated, and glucuronidated conjugates of (epi)catechin and (epi)gallocatechin, exhibiting 101-256nM peak plasma concentration and the time to reach peak plasma concentration ranging from 0.8 to 2.2 h. Plasma pharmacokinetic profiles were similar to those obtained with healthy subjects, indicating that flavan-3-ol absorption occurs in the small intestine. Ileostomists had earlier plasma time to reach peak plasma concentration values than subjects with an intact colon, indicating the absence of an ileal brake. Urine contained 18 metabolites of (epi)catechin and (epi)gallocatechin in amounts corresponding to 6.8±0.6% of total flavan-3-ol intake. However, excretion of (epi)catechin metabolites was equivalent to 27% of the ingested (-)-epicatechin and (+)-catechin.

Original languageEnglish
Pages (from-to)323-334
Number of pages12
JournalMolecular Nutrition & Food Research
Volume54
Issue number3
DOIs
Publication statusPublished - 1 Mar 2010
Externally publishedYes

Keywords

  • Glucuronide and sulphate metabolites
  • Green tea flavan-3-ol bioavailability
  • Ileal and urinary excretion
  • Ileostomists
  • Plasma pharmacokinetics

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