Bioavailability of Green Tea and Coffee Polyphenols (POBAS)
|ClinicalTrials.gov Identifier: NCT03248115|
Recruitment Status : Completed
First Posted : August 14, 2017
Last Update Posted : August 21, 2017
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|
|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|
- Dietary Supplement: Green tea and green coffee extract tablets
- 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.
- 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).
- Completion of study documents: Participants were provided with urine collection sheets, polyphenol questionnaires, checklists to record polyphenol tablet intake, and detailed instructions.
- 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
- 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
- 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
- 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
- Phenolic compounds in tablets [ Time Frame: Through study completion, an average of 3 months ]Quantification of the tablet polyphenol content
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03248115
|MRC HNR Elsie Widdowson Laboratory|
|Cambridge, United Kingdom, CB1 9NL|
|Principal Investigator:||Virginia Tomatis, PhD||MRC HNR|