Bioavailability of Green Tea and Coffee Polyphenols (POBAS)

Bioavailability of Green Tea and Coffee Polyphenols in Healthy Participants

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.

Study Overview

• Status: Completed
• Conditions: Dietary Supplements; Diet, Food, and Nutrition
• Intervention / Treatment: Dietary supplement: Green tea and green coffee extract tablets

• Study Type: Interventional
• Enrollment (Actual): 11
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Cambridge, United Kingdom, CB1 9NL
    • MRC HNR Elsie Widdowson Laboratory

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: NA
• Interventional Model: SINGLE_GROUP
• Masking: NONE

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline phenolic metabolites in urine at 2 weeks	Assessment of the profile of metabolites coming from green tea and green coffee phytochemicals in urine	Week 0 -before supplementation- and week 2
Change from baseline phenolic metabolites in urine at 4 weeks	Assessment of the profile of metabolites coming from green tea and green coffee	Week 0 -before supplementation- and week 4
Change from baseline phenolic metabolites in urine at 8 weeks	Assessment of the profile of metabolites coming from green tea and green coffee	Week 0 -before supplementation- and week 8
Change from baseline phenolic metabolites in urine at 12 weeks	Assessment of the profile of metabolites coming from green tea and green coffee	Week 0 -before supplementation- and week 12 -4 weeks after finishing the supplementation period-

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Phenolic compounds in tablets	Quantification of the tablet polyphenol content	Through study completion, an average of 3 months

Collaborators and Investigators

• Sponsor: MRC Human Nutrition Research
• Investigators: Principal Investigator: Virginia Tomatis, PhD, MRC HNR

Study record dates

Study Major Dates

• Study Start (ACTUAL): April 10, 2013
• Primary Completion (ACTUAL): October 18, 2013
• Study Completion (ACTUAL): October 18, 2013

Study Registration Dates

• First Submitted: August 7, 2017
• First Submitted That Met QC Criteria: August 9, 2017
• First Posted (ACTUAL): August 14, 2017

Study Record Updates

• Last Update Posted (ACTUAL): August 21, 2017
• Last Update Submitted That Met QC Criteria: August 16, 2017
• Last Verified: August 1, 2017

More Information

Terms related to this study

• Keywords: metabolism; polyphenols; green tea catechins; inter-individual variability; coffee caffeoylquinic acids; colonic microbiota
• Other Study ID Numbers: HNR6480

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No