European Journal of Nutrition

, Volume 52, Issue 1, pp 281–288

Simultaneous ingestion of dietary proteins reduces the bioavailability of galloylated catechins from green tea in humans

  • Sarah Egert
  • Jane Tereszczuk
  • Silvia Wein
  • Manfred James Müller
  • Jan Frank
  • Gerald Rimbach
  • Siegfried Wolffram
Original Contribution

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.

Keywords

Catechins Flavan-3-ols Bioavailability Dietary protein Human study 

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Sarah Egert
    • 1
    • 2
  • Jane Tereszczuk
    • 3
  • Silvia Wein
    • 3
  • Manfred James Müller
    • 2
  • Jan Frank
    • 4
    • 5
  • Gerald Rimbach
    • 5
  • Siegfried Wolffram
    • 3
  1. 1.Department of Nutrition and Food Science, Nutritional PhysiologyUniversity of BonnBonnGermany
  2. 2.Department of Human Nutrition, Institute of Human Nutrition and Food ScienceChristian-Albrechts-University of KielKielGermany
  3. 3.Institute of Animal Nutrition and PhysiologyChristian-Albrechts-University of KielKielGermany
  4. 4.Institute of Biological Chemistry and NutritionUniversity of HohenheimStuttgartGermany
  5. 5.Department of Food Science, Institute of Human Nutrition and Food ScienceChristian-Albrechts-University of KielKielGermany

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