Simultaneous Ingestion of Dietary Proteins Reduces the Bioavailability of Galloylated Catechins From Green Tea in Humans

Eur J Nutr. 2013 Feb;52(1):281-8. doi: 10.1007/s00394-012-0330-8. Epub 2012 Feb 25.

Abstract

Purpose: To investigate the influence of dietary proteins (casein, soy protein) and skimmed milk on the plasma kinetics of green tea (GT) catechins.

Methods: In a randomized cross-over design with one-week intervals, 24 healthy normal-weight women consumed a test drink containing 1.75 g GT extract with or without the addition of different proteins. Treatments were GT (control), GT with skimmed milk (GT + M), GT with caseinate (GT + CS), or GT with soy protein (GT + S). Venous blood samples were taken before and several times during a period of 4.5 h after consumption of the test drink. Plasma concentrations of catechins were analyzed by HPLC with electrochemical detection.

Results: Compared to control, consumption of GT with milk, caseinate, or soy protein significantly reduced the bioavailability (mean area under the plasma concentration-time curve) of total catechins (means ± SEM; GT + M, 87 ± 5%; GT + CS, 79 ± 5%; GT + S, 88 ± 4%), epigallocatechin gallate (GT + M, 68 ± 4%; GT + CS, 63 ± 5%; GT + S, 76 ± 5%), and epicatechin gallate (GT + M, 68 ± 5%; GT + CS, 66 ± 6%; GT + S, 77 ± 6%), while the bioavailability of non-galloylated catechins such as epigallocatechin (GT + M, 134 ± 9%; GT + CS, 118 ± 9 %; GT + S, 123 ± 8%) and epicatechin (GT + M, 125 ± 10%; GT + CS, 114 ± 11%; GT + S, 110 ± 8%) significantly increased. No significant differences in bioavailability of GT catechins were observed between the treatments GT + M, GT + CS, or GT + S.

Conclusion: Simultaneous ingestion of dietary proteins reduces the bioavailability of galloylated catechins from GT in humans.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Antioxidants / administration & dosage
  • Antioxidants / pharmacokinetics*
  • Biological Availability
  • Body Mass Index
  • Catechin / administration & dosage
  • Catechin / analogs & derivatives*
  • Catechin / pharmacokinetics
  • Chromatography, High Pressure Liquid
  • Cross-Over Studies
  • Dietary Proteins / administration & dosage*
  • Female
  • Humans
  • Surveys and Questionnaires
  • Tea / chemistry*
  • Young Adult

Substances

  • Antioxidants
  • Dietary Proteins
  • Tea
  • Catechin
  • epicatechin gallate
  • epigallocatechin gallate
  • gallocatechol