Epigallocatechin Gallate Lowers Circulating Catecholamine Concentrations and Alters Lipid Metabolism.
Condition: EGCG Influence on Catecholamine Metabolism
Study type: Interventional
Phase: Phase 4

Summary: 
      The aim of this study was to explore the impact of acute ingestion of the polyphenol
      epigallocatechin galate (EGCG) on catecholamine, catecholamine metabolite, systemic metabolic
      and cardio-vascular variables across a range of exercise intensities during graded cycle
      exercise in man.
    

Detailed description: 
      Written informed consent was obtained from all subjects and all subjects completed the
      AHA/ACSM health screening questionnaire to ascertain their health status and to show their
      eligibility to partake in this study.

      In a randomized, placebo-controlled, single blind, cross-over design study participants
      completed two trials after acute consumption of either EGCG or a placebo (PLAC) supplement
      after an overnight fast. After a two-hour monitoring period following ingestion participants
      performed a continuous graded cycle exercise test to volitional exhaustion. There was at
      least a 7-day washout period between trials.

      Participants were randomly assigned to either the intervention or placebo trial. After an
      overnight fast participants arrived to the laboratory and were observed ingesting two
      capsules each of EGCG (minimum 94% EGCG <0.1% caffeine) from a commercially available brand
      (TEAVIGO™; TAIYO GmbH, 1450 mg) or a placebo (1450 mg Corn Flour). Capsules were weighed and
      sorted to within ±5%. The supplement was consumed in two size 00 vegetarian gelatin capsules
      alongside a standardized amount of distilled water (200ml).

      Experimental Protocol Prior to participation in the experimental trials participants were
      familiarized with the laboratory equipment and the test procedures. On the morning of the
      test participants reported to the Exercise Physiology Laboratory following an 8-10 hour fast
      where standard measures of the participants' body mass, (weighting scales; Seca 770 Digital
      Scales, Seca Ltd, Birmingham, UK) height (stadiometer; Holtain Stadiometer, Holtain Ltd,
      Cymrych, Wales) and body fat percentage using bioelectrical impedance analysis (Bodystat
      Quadscan 4000, Bodystat Ltd, Isle of Man, UK) whilst wearing minimal clothing, were taken.

      Participants were then seated for a 10-minute period while a cannula was inserted into an
      antecubital vein. This was connected to a three-way stopcock for the repeated collection of
      venous blood at rest and during the exercise test. Saline (2-3 ml) was infused regularly keep
      the cannula patent. After a 10-minute rest period a venous blood sample (7 ml) was collected
      into a lithium-heparinised vacutainer. In addition, baseline measures of heart rate (Polar
      RS800CX), and a 10-minute sample of respiratory gas (Jaeger Vyuntus CPX, Erich Jaeger
      GmbH,CareFusion Hoechbegh, Germany) were also taken at this time. Expired air was measured
      for the fractional concentration of oxygen (FEO2%) and carbon dioxide (FECO2%) and for the
      volume of air (SentrySuite Software, Erich Jaeger GmbH,CareFusion Hoechbegh, Germany) expired
      during the period to allow for determination of volumes of O2 utilization and CO2 production.
      These data were used for determination of oxidative energy expenditure using principles of
      indirect calorimetry (Frayn 1983; Jeukendrup & Wallis, 2005).

      Following collection of resting parameters participants were rested in a semi-reclined
      position for two hours. Thereafter, after a 5-minute transition period, participants mounted
      a cycle ergometer (Lode Excalibur Sport Ergometer, Lode BV Groningen, The Netherlands) to
      perform a graded exercise test. Participants were instructed to cycle between 60-70 rpm at an
      initial power output of 60 Watts (W) with an increase in 30 W every 3 minutes. Verbal
      encouragement was provided to the participant throughout. Heart rate was measured constantly
      throughout the exercise test in real-time via a telemetry chest strap and wireless receiver
      (Polar RS800CX) alongside respiratory gas measurements. Two and a half minutes into each
      stage, a rating of perceived exertion (RPE) was taken from the participant (Borg, 1982) and a
      venous blood sample taken. The test continued until volitional exhaustion which was defined
      by the following criteria 1) cadence dropping below 50 rpm, 2) heart rate within 10 beats of
      age-predicted maximum, 3) levelling off of VO2 though workload had increased. At this point
      cardio-respiratory variables were recorded and a final blood sample was taken at exhaustion.

      Participants were given a food and physical activity diaries to complete in the 72 hours
      prior to the first experimental trial. Participants were also instructed to avoid alcohol,
      foods with high polyphenols content and additional green tea consumption during this period.
      Participants were also instructed not to perform any physical activity in the 24h period
      immediately prior to the exercise trial.

      Blood Analyses Venous blood samples were analysed immediately for lactate and glucose levels
      (Biosen C-Line, EKF Diagnostics). Thereafter, the remainder of the sample was centrifuged
      (Heraeus Megafuge 8, Thermo Scientific) for 10 minutes at 3,000 rpm) with ~3ml of plasma
      extracted into individual 1ml microcentrifuge tubes and frozen immediately (-80°C) for later
      analysis of metanephrine, normetanephrine and catecholamine (adrenaline and noradrenaline)
      concentrations using commercially available enzyme linked absorbent assays (ELISA, Eagle
      Biosciences Inc, Nashua, New Hampshire, USA). Blood points selected for use with the assay
      kits were, baseline (REST), two hours post ingestion at rest (POST-ING) and during exercise
      at highest lipid oxidation rate (FATpeak), lactate threshold (LT) and at peak rate of oxygen
      consumption (VO2peak) for each individual were analysed. Lactate threshold was calculated
      using Lactate-E software (Newell et al, 2007).

      The data was analysed using the Statistical Package for the Social Sciences software (Version
      22, SPSS, inc). Data was reported as means±SD with P0.05 accepted. All variables were
      examined using paired t-tests for comparison of experimental trial differences.
    

Intervention name(s): Epigallocatechin gallate; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): 1450mg Corn Flour
Intervention MeSH terms: Epigallocatechin gallate
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Basic Science
Keywords: catecholamines; Exercise; lipid metabolism