Bioavailability of Green Tea and Coffee Polyphenols

NCT03248115 | Completed

• 1 other identifier: HNR6480
• Study Type: interventional
• Target: 11
• Locations: 1 country
• Sites: 1

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.

Conditions

Diet, Food, and Nutrition; Dietary Supplements

Keywords

polyphenols; green tea catechins; coffee caffeoylquinic acids; metabolism; inter-individual variability; colonic microbiota

Outcome Measures

Primary Outcomes (4)

• 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 Outcomes (1)

• Phenolic compounds in tablets

  Through study completion, an average of 3 months

Interventions

Green tea and green coffee extract tablets DIETARY_SUPPLEMENT

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.

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

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

You may not qualify if:

• 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.

Sponsors & Collaborators

• MRC Human Nutrition Research: lead

Study Sites (1)

MRC HNR Elsie Widdowson Laboratory

Cambridge, CB1 9NL, United Kingdom

Location

MeSH Terms

Interventions

Tea

Intervention Hierarchy (Ancestors)

Plant Preparations; Biological Products; Complex Mixtures; Beverages; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages

Study Officials

• Virginia Tomatis, PhD

  MRC HNR

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: August 7, 2017
• First Posted: August 14, 2017
• Study Start: April 10, 2013
• Primary Completion: October 18, 2013
• Study Completion: October 18, 2013
• Last Updated: August 21, 2017

Record last verified: 2017-08

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)