Working...
ClinicalTrials.gov
ClinicalTrials.gov Menu

Bioavailability of Green Tea and Coffee Polyphenols (POBAS)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT03248115
Recruitment Status : Completed
First Posted : August 14, 2017
Last Update Posted : August 21, 2017
Sponsor:
Information provided by (Responsible Party):
Virginia Tomatis, MRC Human Nutrition Research

Brief Summary:

There is little information on the dietary intake, absorption, metabolism and bioavailability (degree to which a substance becomes available to the target tissues upon administration) of polyphenols (natural substances present in a variety of foods) in human participants.

This study assessed the bioavailability in healthy participants of polyphenols from 2 supplements containing green tea and green coffee extracts.

Eleven participants were recruited and their habitual diet was assessed to estimate polyphenol intake. After completing a 24-hour urine collection, participants were given six green tea extract and three green coffee extract tablets, which they took daily for a period of 8 weeks. No tablets were taken during the last 4 weeks of the study. Further 24-hour urines were collected at 2, 4, 8 and 12 weeks.

Participants were required to attend HNR (medical laboratory) the day after each 24hour urine collection. At these visits, they were asked to bring along their urine collections, completed documents (urine collection sheet, checklist for tablet intake/side effects) and any remaining supplements, which were used to assess tablet compliance.

The investigators identified and quantified the amount of polyphenols in the supplement tablets as well as the amount of polyphenols and their metabolites in urine. The investigators then evaluated polyphenol bioavailability from the relationship between their dietary intake and urinary output.

Evidence from this research could inform future intervention studies by providing data on the bioavailability of green tea and coffee polyphenols, and on the individual differences related to phenolic intake.


Condition or disease Intervention/treatment Phase
Diet, Food, and Nutrition Dietary Supplements Dietary Supplement: Green tea and green coffee extract tablets Not Applicable

Layout table for study information
Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 11 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Bioavailability of Green Tea and Coffee Polyphenols in Healthy Participants
Actual Study Start Date : April 10, 2013
Actual Primary Completion Date : October 18, 2013
Actual Study Completion Date : October 18, 2013

Resource links provided by the National Library of Medicine



Intervention Details:
  • Dietary Supplement: Green tea and green coffee extract tablets
    1. Tablets: participants were required to take 6 green tea and 3 green coffee extract tablets daily for a period of 8 weeks. No tablets were taken during the last 4 weeks of the study. Randomly chosen tablets were analysed to quantify their polyphenol content.
    2. Urine collections: Several urine collections were required during the supplementation period in order have sufficient time points to estimate the plateau of the concentration of green tea and coffee polyphenols excreted in the urine to then be able to determine their bioavailability. There was a total of five 24-hour urine collections (at week 0 -before supplementation-, 2, 4, 8, and 12 -4 weeks after finishing the supplementation period).
    3. Completion of study documents: Participants were provided with urine collection sheets, polyphenol questionnaires, checklists to record polyphenol tablet intake, and detailed instructions.


Primary Outcome Measures :
  1. Change from baseline phenolic metabolites in urine at 2 weeks [ Time Frame: Week 0 -before supplementation- and week 2 ]
    Assessment of the profile of metabolites coming from green tea and green coffee phytochemicals in urine

  2. Change from baseline phenolic metabolites in urine at 4 weeks [ Time Frame: Week 0 -before supplementation- and week 4 ]
    Assessment of the profile of metabolites coming from green tea and green coffee

  3. Change from baseline phenolic metabolites in urine at 8 weeks [ Time Frame: Week 0 -before supplementation- and week 8 ]
    Assessment of the profile of metabolites coming from green tea and green coffee

  4. Change from baseline phenolic metabolites in urine at 12 weeks [ Time Frame: Week 0 -before supplementation- and week 12 -4 weeks after finishing the supplementation period- ]
    Assessment of the profile of metabolites coming from green tea and green coffee


Secondary Outcome Measures :
  1. Phenolic compounds in tablets [ Time Frame: Through study completion, an average of 3 months ]
    Quantification of the tablet polyphenol content



Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.


Layout table for eligibility information
Ages Eligible for Study:   18 Years to 45 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Healthy men and women.
  • 18-45 years of age.
  • BMI between 18.5 and 24.9 kg/m2.

Exclusion Criteria:

  • Smoking.
  • Allergy or intolerance to intervention supplements.
  • Chronic, acute or active inflammatory conditions, haematological disorders, or any other systemic illness of renal, hepatic or gastrointestinal origin.
  • Major surgical operations in the gastrointestinal tract or medical treatment for gastrointestinal problems.
  • Active cancer or diagnosis of malignancy within the last five years.
  • Pregnant, lactating, contemplating pregnancy.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03248115


Locations
Layout table for location information
United Kingdom
MRC HNR Elsie Widdowson Laboratory
Cambridge, United Kingdom, CB1 9NL
Sponsors and Collaborators
MRC Human Nutrition Research
Investigators
Layout table for investigator information
Principal Investigator: Virginia Tomatis, PhD MRC HNR

Layout table for additonal information
Responsible Party: Virginia Tomatis, Principal Investigator, MRC Human Nutrition Research
ClinicalTrials.gov Identifier: NCT03248115     History of Changes
Other Study ID Numbers: HNR6480
First Posted: August 14, 2017    Key Record Dates
Last Update Posted: August 21, 2017
Last Verified: August 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Layout table for additional information
Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No

Keywords provided by Virginia Tomatis, MRC Human Nutrition Research:
polyphenols
green tea catechins
coffee caffeoylquinic acids
metabolism
inter-individual variability
colonic microbiota