Effects of timing of acute catechin-rich green tea ingestion on postprandial glucose metabolism in healthy men

J Nutr Biochem. 2019 Nov;73:108221. doi: 10.1016/j.jnutbio.2019.108221. Epub 2019 Aug 15.


Green tea polyphenols, particularly catechins, decrease fasting and postprandial glucose. However, no studies have compared the timing of green tea ingestion on glucose metabolism and changes in catechin concentrations. Here, we examined the effects of timing of acute catechin-rich green tea ingestion on postprandial glucose metabolism in young men. Seventeen healthy young men completed four trials involving blood collection in a fasting state and at 30, 60, 120, and 180 min after meal consumption in a random order: 1) morning placebo trial (09:00 h; MP trial), 2) evening placebo trial (17:00 h; EP trial), 3) morning catechin-rich green tea trial (09:00 h; MGT trial), and 4) evening catechin-rich green tea trial (17:00 h; EGT trial). The concentrations of glucose at 120 min (P=.031) and 180 min (P=.013) after meal intake were significantly higher in the MGT trials than in the MP trials. Additionally, the concentration of glucose was significantly lower in EGT trials than in the EP trials at 60 min (P=.014). Moreover, the concentrations of glucose-dependent insulinotropic polypeptide were significantly lower in the green tea trials than in the placebo trials at 30 min (morning: P=.010, evening: P=.006) and 60 min (morning: P=.001, evening: P=.006) after meal intake in both the morning and evening trials. Our study demonstrated that acute ingestion of catechin-rich green tea in the evening reduced postprandial plasma glucose concentrations.

Keywords: Circadian rhythm; Epigallocatechin gallate; Glucose metabolism; Incretin; Meal timing.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Glucose / analysis*
  • Catechin / administration & dosage*
  • Catechin / analogs & derivatives
  • Circadian Rhythm*
  • Cross-Over Studies
  • Double-Blind Method
  • Fasting
  • Fatty Acids, Nonesterified / blood
  • Gastric Inhibitory Polypeptide / blood
  • Glucagon-Like Peptide 1 / blood
  • Humans
  • Insulin / blood
  • Male
  • Meals
  • Placebos
  • Postprandial Period*
  • Tea*
  • Time Factors
  • Triglycerides / blood
  • Young Adult


  • Blood Glucose
  • Fatty Acids, Nonesterified
  • Insulin
  • Placebos
  • Tea
  • Triglycerides
  • Gastric Inhibitory Polypeptide
  • Glucagon-Like Peptide 1
  • Catechin
  • epigallocatechin gallate