Overweight and ObesityGreenTeaNCT04628624
Green Tea Supplementation, Fat Oxidation and Body Composition in Overweight Individuals
A study testing GTE 1 and GTE 2 in people with Overweight and Obesity and Fat Burn, run by Anglia Ruskin University at 1 site in United Kingdom.
Trial summary
The purpose of this study is to investigate the effects of green tea extract (GTE) on fat oxidation, body composition and exercise performance in overweight individuals. The study will be conducted under laboratory conditions following an 8 week supplemental period. Read more about this study
- Who is it for?
- Ages 18 to 55 yearsHealthy volunteers can take part
- Conditions the study is for
- Overweight and Obesity, Fat Burn
- What is being tested?
- GTE 1 and GTE 2
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 30 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 1 Dec 2018to 1 Mar 2020
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 55 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Men and women, UK based, above 18 years of age
- Below 45 years of age (for men) and below 55 years of age (for women)
- Baseline maximal oxygen uptake >25ml/kg/min and <45ml/kg/min representative of normal (but not high) fitness levels; and a body mass index (BMI) >25kg/m2 and <33kg/m2
- All participants: No known history (including family history) of heart abnormalities, hypertension, coronary heart disease or diabetes (determined from pre-study health screen questionnaire)
- All participants: No known history of liver related disorders (e.g. hepatitis, Wilsons disease, cirrhosis).
- All participants: Not currently suffering from any musculo-skeletal injury, or any other reason that may prevent participation in cardiovascular exercise
Show all 10Show fewer
- All participants: Have not suffered from recent viral infections ie: influenza (defined within the prior 2 months)
- All participants: Not suffering from any known blood related disorders, including blood coagulation abnormalities, or have any adverse reactions to blood taking
- All participants: Not taking any prescribed or over-the-counter medication which may influence exercise training (with the exception of inhalers for exercise induced asthma or contraceptive pill)
- All participants: Not consuming or prepared to refrain from consumption, any commercial supplementation which conflicts with the study parameters ie: creatine, other green tea or weight loss products.
Who cannot join
- Anyone below the age of 18 years, or above 45 years (for men) and 55 years (for women) - based on exercise testing guidelines by the American College of Sports Medicine (ACSM).
- Those who do not meet the criteria for baseline maximal oxygen uptake or BMI assessment
- All participants: anyone with a known history (including family history) of heart abnormalities, hypertension, coronary heart disease or diabetes (determined from pre-study health screen questionnaire)
- All participants: anyone with a known previous history of liver related disorders.
- All participants: Anyone suffering from a current musculo-skeletal injury, or any other reason that may prevent participation in cardiovascular exercise
- All participants: those suffering from recent viral infections ie: influenza (defined within the prior 2 months)
Show all 10Show fewer
- All participants: Those with known blood related disorders, including blood coagulation abnormalities, or have any adverse reactions to blood taking. This includes any participant who has or potentially has an infectious disease, inc. HIV, and all types of hepatitis.
- All participants: Anyone taking any prescribed or over-the-counter medication which may influence exercise training (with the exception of inhalers for exercise induced asthma or contraceptive pill)
- All participants: Anyone consuming or not prepared to refrain from consumption, any commercial supplementation which conflicts with the study parameters ie: creatine, other green tea or weight loss products.
- FEMALE ONLY: Any participant who is, suspects they may be or becomes pregnant during the study.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Effect of Green Tea Supplementation Strategies on Fat Oxidation and Body Composition in Overweight Individuals
The purpose of this study is to investigate the effects of green tea extract (GTE) on fat oxidation, body composition and exercise performance in overweight individuals. The study will be conducted under laboratory conditions following an 8 week supplemental period. Participants will be required to attend the laboratory for a pre-screening/familiarisation trial followed by assessments at week 0 (baseline), week 2, 4 and 8. Across the intervention, participants will maintain habitual dietary intake and follow a prescribed exercise programme. Additionally participants will be randomised to either a placebo, green tea extract or GTE with antioxidant supplementation.
It is hypothesised that the addition of antioxidants with GTE will enhance fat oxidation in overweight individuals more than GTE or placebo. It is further hypothesised that such improvements in fat oxidation due to GTE will lead to improvements in both body composition variables and submaximal exercise performance (metabolic efficiency) in overweight, but otherwise healthy persons.
Read the detailed description
The health benefits of polyphenols found in green tea (GT), the unfermented leaves of the tea plant, Camellia sinensis, are of current scientific interest. These health benefits, in part, relate to the bioactive catechin polyphenol content of GT, of which (-)-epigallocatechin-3-gallate (EGCG) can account for between 50-80% of the total catechin content. GT catechins have been proposed to influence metabolic and thermogenic activities in the short term, leading to enhanced fat oxidation capacity, although this has been disputed.
Research investigating GT extracts (GTE) and exercise have produced conflicting results. Modest EGCG dosage in the short term (270 mg·d-1 EGCG for 6 days, and 68 mg·d-1 EGCG for 3 weeks) did not alter metabolic or performance variables in healthy or endurance trained volunteers. However, the inclusion of 100.5 mg·d-1 EGCG over a 10 week training period enhanced whole-body metabolic efficiency elsewhere. One confounding factor though is the use of caffeinated GTE in these studies. When decaffeinated GTE (dGTE) has been employed, 366 mg EGCG was found to acutely increase fat oxidation by 17%. Indeed a recent publication from our research group investigating the short term use of dGTE demonstrated positive changes in fat oxidation in healthy volunteers. However, less is known as to whether dGTE (or indeed combinations of dGTE with antioxidant nutrients which may improve GTE bioavailability) could provide similar results in overweight or sedentary individuals embarking on an exercise programme.
The aim of this research proposal is therefore to assess the impact of two GTE strategies on fat oxidation, cardiometabolic health, visceral fat reduction, and exercise performance in a healthy, but overweight cohort undertaking a standardised exercise training programme.
Research Questions:
Q1: Does regular consumption of dGTE favourably enhance fat oxidation and/or improve variables associated with cardiometabolic health and body composition in comparison to a placebo supplement in healthy, but overweight individuals? Q2: Does a dGTE complex (including key antioxidant nutrients) enhance fat oxidation and/or improve variables associated with cardiometabolic health and body composition more so than dGTE or placebo supplementation in healthy, but overweight individuals?
This study will involve participants attending sessions at Compass House, ARU, undertaking the following:
- Baseline trial: all participants will attend a subject briefing, provide written, informed consent prior to participation. Following this, all participants will undertake a baseline test for maximal fat oxidation rates (FATmax) and oxygen uptake using a standardised incremental cycling exercise protocol and expired air analysis
- Intervention period: participants will be randomly assigned to either dGTE (400mg EGCG daily), dGTE with antioxidants (150mg quercetin, 150mg alpha-lipoic acid) or placebo for 8 weeks. During this period, participants will undertake regular aerobic exercise (3x/ week; 45mins; at ~ FATmax intensity)
- Experimental evaluation of progress will be assessed at weeks 0,2,4, and 8. During laboratory visits, participants will be required to have a single venepuncture blood sample, assessment of blood pressure/ body composition (skinfold, bioelectrical impedance, waist circumference), assessment of FATmax, and assessment of fat oxidation during steady state exercise at FATmax.
- Conditions
- Overweight and Obesity, Fat Burn
- Being tested
- Placebo control, GTE 1, GTE 2
- Keywords
- Green Tea, Exercise Metabolism
- Medical subject headings
- Overweight, Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Placebo controlDietary supplement
Also called Placebo
8 week supplementation period, with participants consuming 2 capsules per day containing potato starch
GTE 1Dietary supplement
Also called Decaffeinated green tea extract
8 week supplementation period, with participants consuming 2 capsules per day containing green tea extract (571mg/d)
GTE 2Dietary supplement
Also called Decaffeinated green tea extract and antioxidants
8 week supplementation period, with participants consuming 2 capsules per day containing green tea extract with additional antioxidants (150mg of quercitin and 150mg of alpha lipoic acid)
| Study group | Role | What they receive |
|---|---|---|
| Placebo group | Placebo comparator | Placebo - capsulated, colour matched potato starch (~450mg per capsule) - provided by Biocare Ltd., UK using standard 00 vegetable capsules (hydroxypropyl methylcellulose). Dosage: 2 divided doses (1 capsule mid morning, 1 capsule mid afternoon) - daily for 8 weeks. Receives: Dietary Supplement: Placebo control |
| Green tea 1 | Experimental | Capsulated decaffeinated green tea extract (dGTE) (standardised to 70% EGCG concentration, 571mg total per day, containing 400mg EGCG - provided by Biocare Ltd., UK using standard 00 vegetable capsules (hydroxypropyl methylcellulose). Dosage: 2 divided doses (1 capsule mid morning, 1 capsule mid afternoon) - daily for 8 weeks. Receives: Dietary Supplement: GTE 1 |
| Green tea 2 | Experimental | Capsulated decaffeinated green tea extract (dGTE) (standardised to 70% EGCG concentration, 571mg total per day, containing 400mg EGCG + 150mg quercitin and 150mg alpha lipoic acid - provided by Biocare Ltd., UK using standard 00 vegetable capsules (hydroxypropyl methylcellulose). Dosage: 2 divided doses (1 capsule mid morning, 1 capsule mid afternoon) - daily for 8 weeks. Receives: Dietary Supplement: GTE 2 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Fat oxidation (max)
Assessment of maximal fat oxidation rate (via expired air) during incremental exercise
Measured: Change from Baseline maximal fat oxidation at 1 month
Fat oxidation (max)
Assessment of maximal fat oxidation rate (via expired air) during incremental exercise
Measured: Change from Baseline maximal fat oxidation at 2 months
Fat oxidation (min)
Assessment of exercise intensity at which point fat oxidation is negligable
Measured: Change from Baseline minimum fat oxidation at 1 month
Fat oxidation (min)
Assessment of exercise intensity at which point fat oxidation is negligable
Measured: Change from Baseline minimum fat oxidation at 2 months
Secondary outcomes (30)
Height
Assessment of height (in metres)
Measured: Change from baseline height at 1 month
Height
Assessment of height (in metres)
Measured: Change from baseline height at 2 months
Weight
Assessment of weight (in kilograms)
Measured: Change from baseline weight at 1 month
Weight
Assessment of weight (in kilograms)
Measured: Change from baseline weight at 2 months
Bodyfat percentage
Assessment of bodyfat (%)
Measured: Change from baseline bodyfat percentage at 1 month
Bodyfat percentage
Assessment of bodyfat (%)
Measured: Change from baseline bodyfat percentage at 2 months
Waist to hip ratio
Assessment of waist to hip ratio (cm)
Measured: Change from baseline waist to hip ratio at 1 month
Waist to hip ratio
Assessment of waist to hip ratio (cm)
Measured: Change from baseline waist to hip ratio at 2 months
Body mass index
Assessment of body mass index or BMI (measured in kilograms per metre squared)
Measured: Change from baseline BMI at 1 month
Body mass index
Assessment of body mass index or BMI (measured in kilograms per metre squared)
Measured: Change from baseline BMI at 2 months
Central abdomen depth
Assessment of central abdomen depth (in cm)
Measured: Change from baseline central abdominal depth at 1 month
Central abdomen depth
Assessment of central abdomen depth (in cm)
Measured: Change from baseline central abdominal depth at 2 months
Blood cholesterol
Assessment of total cholesterol, triglycerides, HDL-c and LDL-c (all in mmol/L)
Measured: Change from Baseline at 1 month
Blood cholesterol
Assessment of total cholesterol, triglycerides, HDL-c and LDL-c (all in mmol/L)
Measured: Change from Baseline at 2 months
Blood glucose
Assessment of blood glucose (in mmol/L)
Measured: Change from Baseline blood glucose at 1 month
Blood glucose
Assessment of blood glucose (in mmol/L)
Measured: Change from Baseline blood glucose at 2 months
Blood insulin
Assessment of blood glucose (in pmol/L)
Measured: Change from Baseline blood insulin at 1 month
Blood insulin
Assessment of blood glucose (in pmol/L)
Measured: Change from Baseline blood insulin at 2 months
Blood leptin
Assessment of blood leptin (in ng/ml)
Measured: Change from Baseline blood leptin at 1 month
Blood leptin
Assessment of blood leptin (in ng/ml)
Measured: Change from Baseline blood leptin at 2 months
Blood adiponectin
Assessment of blood adiponectin (in ug/ml)
Measured: Change from Baseline blood adiponectin at 1 month
Blood adiponectin
Assessment of blood adiponectin (in ug/ml)
Measured: Change from Baseline blood adiponectin at 2 months
Blood fatty acids and glycerol
Assessment of blood free fatty acids and glycerol (both in umol/L)
Measured: Change from Baseline at 1 month
Blood fatty acids and glycerol
Assessment of blood free fatty acids and glycerol (both in umol/L)
Measured: Change from Baseline at 2 months
Blood liver enzymes
Assessment of blood liver enzymes including alanine aminotransferase(ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) (all measured in U/L)
Measured: Change from baseline at 1 month
Blood liver enzymes
Assessment of blood liver enzymes including alanine aminotransferase(ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) (all measured in U/L)
Measured: Change from baseline at 2 months
Blood bilirubin
Assessment of blood concentration of bilirubin (in umol/L)
Measured: Change from baseline bilirubin at 1 month
Blood bilirubin
Assessment of blood concentration of bilirubin (in umol/L)
Measured: Change from baseline bilirubin at 2 months
Respiratory measures (oxygen, carbon dioxide) during steady state exercise
Assessment of expired oxygen and carbon dioxide (in litres per minute)
Measured: Change from baseline at 1 month
Respiratory measures (oxygen, carbon dioxide) during steady state exercise
Assessment of mean expired oxygen and carbon dioxide (in litres per minute)
Measured: Change from baseline at 2 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Nov 2020
- Study start1 Dec 2018
- Primary completion1 Dec 2019
- Study completion1 Mar 2020
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (13)Papers the sponsor has linked to this study.
- Other trials for Overweight and ObesityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants randomly assigned to either placebo, green tea extract (GTE) or GTE with antioxidants in a parallel, double blind manner
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 30 participants (actual)
Sponsor and investigators
- Lead sponsor
- Anglia Ruskin University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Justin Roberts, Anglia Ruskin University
- Investigators
- Justin Roberts, PhD, Principal investigator, Anglia Ruskin University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04628624
- Sponsor's protocol ID
- FST/FREP/17/703
- Acronym
- GreenTea
- Status last verified
- Nov 2020
- First submitted
- 5 Nov 2020
- Last updated
- 13 Nov 2020
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Roberts JD, Roberts MG, Tarpey MD, Weekes JC, Thomas CH. The effect of a decaffeinated green tea extract formula on fat oxidation, body composition and exercise performance. J Int Soc Sports Nutr. 2015 Jan 21;12(1):1. doi: 10.1186/s12970-014-0062-7. eCollection 2015.
PubMed 25650043Hursel R, Viechtbauer W, Westerterp-Plantenga MS. The effects of green tea on weight loss and weight maintenance: a meta-analysis. Int J Obes (Lond). 2009 Sep;33(9):956-61. doi: 10.1038/ijo.2009.135. Epub 2009 Jul 14.
PubMed 19597519Hursel R, Westerterp-Plantenga MS. Thermogenic ingredients and body weight regulation. Int J Obes (Lond). 2010 Apr;34(4):659-69. doi: 10.1038/ijo.2009.299. Epub 2010 Feb 9.
PubMed 20142827Ichinose T, Nomura S, Someya Y, Akimoto S, Tachiyashiki K, Imaizumi K. Effect of endurance training supplemented with green tea extract on substrate metabolism during exercise in humans. Scand J Med Sci Sports. 2011 Aug;21(4):598-605. doi: 10.1111/j.1600-0838.2009.01077.x. Epub 2010 Mar 10.
PubMed 20459475Venables MC, Hulston CJ, Cox HR, Jeukendrup AE. Green tea extract ingestion, fat oxidation, and glucose tolerance in healthy humans. Am J Clin Nutr. 2008 Mar;87(3):778-84. doi: 10.1093/ajcn/87.3.778.
PubMed 18326618Dulloo AG, Duret C, Rohrer D, Girardier L, Mensi N, Fathi M, Chantre P, Vandermander J. Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. Am J Clin Nutr. 1999 Dec;70(6):1040-5. doi: 10.1093/ajcn/70.6.1040.
PubMed 10584049Ryu OH, Lee J, Lee KW, Kim HY, Seo JA, Kim SG, Kim NH, Baik SH, Choi DS, Choi KM. Effects of green tea consumption on inflammation, insulin resistance and pulse wave velocity in type 2 diabetes patients. Diabetes Res Clin Pract. 2006 Mar;71(3):356-8. doi: 10.1016/j.diabres.2005.08.001. Epub 2005 Sep 19.
PubMed 16169629Maki KC, Reeves MS, Farmer M, Yasunaga K, Matsuo N, Katsuragi Y, Komikado M, Tokimitsu I, Wilder D, Jones F, Blumberg JB, Cartwright Y. Green tea catechin consumption enhances exercise-induced abdominal fat loss in overweight and obese adults. J Nutr. 2009 Feb;139(2):264-70. doi: 10.3945/jn.108.098293. Epub 2008 Dec 11.
PubMed 19074207Feng WY. Metabolism of green tea catechins: an overview. Curr Drug Metab. 2006 Oct;7(7):755-809. doi: 10.2174/138920006778520552.
PubMed 17073579Hodgson AB, Randell RK, Jeukendrup AE. The effect of green tea extract on fat oxidation at rest and during exercise: evidence of efficacy and proposed mechanisms. Adv Nutr. 2013 Mar 1;4(2):129-40. doi: 10.3945/an.112.003269.
PubMed 23493529Dean S, Braakhuis A, Paton C. The effects of EGCG on fat oxidation and endurance performance in male cyclists. Int J Sport Nutr Exerc Metab. 2009 Dec;19(6):624-44. doi: 10.1123/ijsnem.19.6.624.
PubMed 20175431Eichenberger P, Colombani PC, Mettler S. Effects of 3-week consumption of green tea extracts on whole-body metabolism during cycling exercise in endurance-trained men. Int J Vitam Nutr Res. 2009 Jan;79(1):24-33. doi: 10.1024/0300-9831.79.1.24.
PubMed 19839000Achten J, Jeukendrup AE. Maximal fat oxidation during exercise in trained men. Int J Sports Med. 2003 Nov;24(8):603-8. doi: 10.1055/s-2003-43265.
PubMed 14598198
Study at a glance
From the registry record, last updated by the sponsor on 13 Nov 2020. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Green Tea Supplementation Strategies on Fat Oxidation and Body Composition in Overweight Individuals
- ClinicalTrials.gov ID
- NCT04628624
- Acronym / sponsor ID
- GreenTea / FST/FREP/17/703
- Conditions
- Overweight and Obesity, Fat Burn
- Keywords
- Green Tea, Exercise Metabolism
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 30 participants (actual)
- Lead sponsor
- Anglia Ruskin UniversityUniversity, hospital or other
- Study start
- 1 Dec 2018 (actual)
- Primary completion
- 1 Dec 2019 (actual)
- Study completion
- 1 Mar 2020 (actual)
- First posted
- 13 Nov 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to investigate the effects of green tea extract (GTE) on fat oxidation, body composition and exercise performance in overweight individuals. The study will be conducted under laboratory conditions following an 8 week supplemental period. Participants will be required to attend the laboratory for a pre-screening/familiarisation trial followed by assessments at week 0 (baseline), week 2, 4 and 8. Across the intervention, participants will maintain habitual dietary intake and follow a prescribed exercise programme. Additionally participants will be randomised to either a placebo, green tea extract or GTE with antioxidant supplementation.
It is hypothesised that the addition of antioxidants with GTE will enhance fat oxidation in overweight individuals more than GTE or placebo. It is further hypothesised that such improvements in fat oxidation due to GTE will lead to improvements in both body composition variables and submaximal exercise performance (metabolic efficiency) in overweight, but otherwise healthy persons.
Detailed description
The health benefits of polyphenols found in green tea (GT), the unfermented leaves of the tea plant, Camellia sinensis, are of current scientific interest. These health benefits, in part, relate to the bioactive catechin polyphenol content of GT, of which (-)-epigallocatechin-3-gallate (EGCG) can account for between 50-80% of the total catechin content. GT catechins have been proposed to influence metabolic and thermogenic activities in the short term, leading to enhanced fat oxidation capacity, although this has been disputed.
Research investigating GT extracts (GTE) and exercise have produced conflicting results. Modest EGCG dosage in the short term (270 mg·d-1 EGCG for 6 days, and 68 mg·d-1 EGCG for 3 weeks) did not alter metabolic or performance variables in healthy or endurance trained volunteers. However, the inclusion of 100.5 mg·d-1 EGCG over a 10 week training period enhanced whole-body metabolic efficiency elsewhere. One confounding factor though is the use of caffeinated GTE in these studies. When decaffeinated GTE (dGTE) has been employed, 366 mg EGCG was found to acutely increase fat oxidation by 17%. Indeed a recent publication from our research group investigating the short term use of dGTE demonstrated positive changes in fat oxidation in healthy volunteers. However, less is known as to whether dGTE (or indeed combinations of dGTE with antioxidant nutrients which may improve GTE bioavailability) could provide similar results in overweight or sedentary individuals embarking on an exercise programme.
The aim of this research proposal is therefore to assess the impact of two GTE strategies on fat oxidation, cardiometabolic health, visceral fat reduction, and exercise performance in a healthy, but overweight cohort undertaking a standardised exercise training programme.
Research Questions:
Q1: Does regular consumption of dGTE favourably enhance fat oxidation and/or improve variables associated with cardiometabolic health and body composition in comparison to a placebo supplement in healthy, but overweight individuals? Q2: Does a dGTE complex (including key antioxidant nutrients) enhance fat oxidation and/or improve variables associated with cardiometabolic health and body composition more so than dGTE or placebo supplementation in healthy, but overweight individuals?
This study will involve participants attending sessions at Compass House, ARU, undertaking the following:
- Baseline trial: all participants will attend a subject briefing, provide written, informed consent prior to participation. Following this, all participants will undertake a baseline test for maximal fat oxidation rates (FATmax) and oxygen uptake using a standardised incremental cycling exercise protocol and expired air analysis
- Intervention period: participants will be randomly assigned to either dGTE (400mg EGCG daily), dGTE with antioxidants (150mg quercetin, 150mg alpha-lipoic acid) or placebo for 8 weeks. During this period, participants will undertake regular aerobic exercise (3x/ week; 45mins; at ~ FATmax intensity)
- Experimental evaluation of progress will be assessed at weeks 0,2,4, and 8. During laboratory visits, participants will be required to have a single venepuncture blood sample, assessment of blood pressure/ body composition (skinfold, bioelectrical impedance, waist circumference), assessment of FATmax, and assessment of fat oxidation during steady state exercise at FATmax.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
- Model description
- Participants randomly assigned to either placebo, green tea extract (GTE) or GTE with antioxidants in a parallel, double blind manner
| Arm | Type | Receives |
|---|---|---|
| Placebo group | Placebo comparator | Dietary Supplement: Placebo controlPlacebo - capsulated, colour matched potato starch (~450mg per capsule) - provided by Biocare Ltd., UK using standard 00 vegetable capsules (hydroxypropyl methylcellulose). Dosage: 2 divided doses (1 capsule mid morning, 1 capsule mid afternoon) - daily for 8 weeks. |
| Green tea 1 | Experimental | Dietary Supplement: GTE 1Capsulated decaffeinated green tea extract (dGTE) (standardised to 70% EGCG concentration, 571mg total per day, containing 400mg EGCG - provided by Biocare Ltd., UK using standard 00 vegetable capsules (hydroxypropyl methylcellulose). Dosage: 2 divided doses (1 capsule mid morning, 1 capsule mid afternoon) - daily for 8 weeks. |
| Green tea 2 | Experimental | Dietary Supplement: GTE 2Capsulated decaffeinated green tea extract (dGTE) (standardised to 70% EGCG concentration, 571mg total per day, containing 400mg EGCG + 150mg quercitin and 150mg alpha lipoic acid - provided by Biocare Ltd., UK using standard 00 vegetable capsules (hydroxypropyl methylcellulose). Dosage: 2 divided doses (1 capsule mid morning, 1 capsule mid afternoon) - daily for 8 weeks. |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (10 listed)
- Men and women, UK based, above 18 years of age
- Below 45 years of age (for men) and below 55 years of age (for women)
- Baseline maximal oxygen uptake >25ml/kg/min and <45ml/kg/min representative of normal (but not high) fitness levels; and a body mass index (BMI) >25kg/m2 and <33kg/m2
- All participants: No known history (including family history) of heart abnormalities, hypertension, coronary heart disease or diabetes (determined from pre-study health screen questionnaire)
- All participants: No known history of liver related disorders (e.g. hepatitis, Wilsons disease, cirrhosis).
Key exclusion criteria (10 listed)
- Anyone below the age of 18 years, or above 45 years (for men) and 55 years (for women) - based on exercise testing guidelines by the American College of Sports Medicine (ACSM).
- Those who do not meet the criteria for baseline maximal oxygen uptake or BMI assessment
- All participants: anyone with a known history (including family history) of heart abnormalities, hypertension, coronary heart disease or diabetes (determined from pre-study health screen questionnaire)
- All participants: anyone with a known previous history of liver related disorders.
- All participants: Anyone suffering from a current musculo-skeletal injury, or any other reason that may prevent participation in cardiovascular exercise
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Placebo controlAlso: Placebo8 week supplementation period, with participants consuming 2 capsules per day containing potato starch | Dietary supplement | Placebo group |
| GTE 1Also: Decaffeinated green tea extract8 week supplementation period, with participants consuming 2 capsules per day containing green tea extract (571mg/d) | Dietary supplement | Green tea 1 |
| GTE 2Also: Decaffeinated green tea extract and antioxidants8 week supplementation period, with participants consuming 2 capsules per day containing green tea extract with additional antioxidants (150mg of quercitin and 150mg of alpha lipoic acid) | Dietary supplement | Green tea 2 |
Primary outcome
Fat oxidation (max)
Time frame: Change from Baseline maximal fat oxidation at 1 month
Assessment of maximal fat oxidation rate (via expired air) during incremental exercise
Fat oxidation (max)
Time frame: Change from Baseline maximal fat oxidation at 2 months
Assessment of maximal fat oxidation rate (via expired air) during incremental exercise
Fat oxidation (min)
Time frame: Change from Baseline minimum fat oxidation at 1 month
Assessment of exercise intensity at which point fat oxidation is negligable
Fat oxidation (min)
Time frame: Change from Baseline minimum fat oxidation at 2 months
Assessment of exercise intensity at which point fat oxidation is negligable
30 secondary outcomes
Height
Time frame: Change from baseline height at 1 month
Height
Time frame: Change from baseline height at 2 months
Weight
Time frame: Change from baseline weight at 1 month
Weight
Time frame: Change from baseline weight at 2 months
Bodyfat percentage
Time frame: Change from baseline bodyfat percentage at 1 month
Bodyfat percentage
Time frame: Change from baseline bodyfat percentage at 2 months
Waist to hip ratio
Time frame: Change from baseline waist to hip ratio at 1 month
Waist to hip ratio
Time frame: Change from baseline waist to hip ratio at 2 months
Body mass index
Time frame: Change from baseline BMI at 1 month
Body mass index
Time frame: Change from baseline BMI at 2 months
Central abdomen depth
Time frame: Change from baseline central abdominal depth at 1 month
Central abdomen depth
Time frame: Change from baseline central abdominal depth at 2 months
Blood cholesterol
Time frame: Change from Baseline at 1 month
Blood cholesterol
Time frame: Change from Baseline at 2 months
Blood glucose
Time frame: Change from Baseline blood glucose at 1 month
Blood glucose
Time frame: Change from Baseline blood glucose at 2 months
Blood insulin
Time frame: Change from Baseline blood insulin at 1 month
Blood insulin
Time frame: Change from Baseline blood insulin at 2 months
Blood leptin
Time frame: Change from Baseline blood leptin at 1 month
Blood leptin
Time frame: Change from Baseline blood leptin at 2 months
Blood adiponectin
Time frame: Change from Baseline blood adiponectin at 1 month
Blood adiponectin
Time frame: Change from Baseline blood adiponectin at 2 months
Blood fatty acids and glycerol
Time frame: Change from Baseline at 1 month
Blood fatty acids and glycerol
Time frame: Change from Baseline at 2 months
Blood liver enzymes
Time frame: Change from baseline at 1 month
Blood liver enzymes
Time frame: Change from baseline at 2 months
Blood bilirubin
Time frame: Change from baseline bilirubin at 1 month
Blood bilirubin
Time frame: Change from baseline bilirubin at 2 months
Respiratory measures (oxygen, carbon dioxide) during steady state exercise
Time frame: Change from baseline at 1 month
Respiratory measures (oxygen, carbon dioxide) during steady state exercise
Time frame: Change from baseline at 2 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Nov 2020.
- Background: PubMed 25650043Roberts JD, Roberts MG, Tarpey MD, Weekes JC, Thomas CH. The effect of a decaffeinated green tea extract formula on fat oxidation, body composition and exercise performance. J Int Soc Sports Nutr. 2015 Jan 21;12(1):1. doi: 10.1186/s12970-014-0062-7. eCollection 2015.
- Background: PubMed 19597519Hursel R, Viechtbauer W, Westerterp-Plantenga MS. The effects of green tea on weight loss and weight maintenance: a meta-analysis. Int J Obes (Lond). 2009 Sep;33(9):956-61. doi: 10.1038/ijo.2009.135. Epub 2009 Jul 14.
- Background: PubMed 20142827Hursel R, Westerterp-Plantenga MS. Thermogenic ingredients and body weight regulation. Int J Obes (Lond). 2010 Apr;34(4):659-69. doi: 10.1038/ijo.2009.299. Epub 2010 Feb 9.
- Background: PubMed 20459475Ichinose T, Nomura S, Someya Y, Akimoto S, Tachiyashiki K, Imaizumi K. Effect of endurance training supplemented with green tea extract on substrate metabolism during exercise in humans. Scand J Med Sci Sports. 2011 Aug;21(4):598-605. doi: 10.1111/j.1600-0838.2009.01077.x. Epub 2010 Mar 10.
- Background: PubMed 18326618Venables MC, Hulston CJ, Cox HR, Jeukendrup AE. Green tea extract ingestion, fat oxidation, and glucose tolerance in healthy humans. Am J Clin Nutr. 2008 Mar;87(3):778-84. doi: 10.1093/ajcn/87.3.778.
- Background: PubMed 10584049Dulloo AG, Duret C, Rohrer D, Girardier L, Mensi N, Fathi M, Chantre P, Vandermander J. Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. Am J Clin Nutr. 1999 Dec;70(6):1040-5. doi: 10.1093/ajcn/70.6.1040.
- Background: PubMed 16169629Ryu OH, Lee J, Lee KW, Kim HY, Seo JA, Kim SG, Kim NH, Baik SH, Choi DS, Choi KM. Effects of green tea consumption on inflammation, insulin resistance and pulse wave velocity in type 2 diabetes patients. Diabetes Res Clin Pract. 2006 Mar;71(3):356-8. doi: 10.1016/j.diabres.2005.08.001. Epub 2005 Sep 19.
- Background: PubMed 19074207Maki KC, Reeves MS, Farmer M, Yasunaga K, Matsuo N, Katsuragi Y, Komikado M, Tokimitsu I, Wilder D, Jones F, Blumberg JB, Cartwright Y. Green tea catechin consumption enhances exercise-induced abdominal fat loss in overweight and obese adults. J Nutr. 2009 Feb;139(2):264-70. doi: 10.3945/jn.108.098293. Epub 2008 Dec 11.
- Background: PubMed 17073579Feng WY. Metabolism of green tea catechins: an overview. Curr Drug Metab. 2006 Oct;7(7):755-809. doi: 10.2174/138920006778520552.
- Background: PubMed 23493529Hodgson AB, Randell RK, Jeukendrup AE. The effect of green tea extract on fat oxidation at rest and during exercise: evidence of efficacy and proposed mechanisms. Adv Nutr. 2013 Mar 1;4(2):129-40. doi: 10.3945/an.112.003269.
- Background: PubMed 20175431Dean S, Braakhuis A, Paton C. The effects of EGCG on fat oxidation and endurance performance in male cyclists. Int J Sport Nutr Exerc Metab. 2009 Dec;19(6):624-44. doi: 10.1123/ijsnem.19.6.624.
- Background: PubMed 19839000Eichenberger P, Colombani PC, Mettler S. Effects of 3-week consumption of green tea extracts on whole-body metabolism during cycling exercise in endurance-trained men. Int J Vitam Nutr Res. 2009 Jan;79(1):24-33. doi: 10.1024/0300-9831.79.1.24.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Justin Roberts, PhD principal investigator
Anglia Ruskin University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing GTE 1 and GTE 2 in people with Overweight and Obesity and Fat Burn, run by Anglia Ruskin University at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 13 Nov 2020. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Fat oxidation (max) (time frame: Change from Baseline maximal fat oxidation at 1 month). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04628624, which also lists 13 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Nov 2020.