Bioavailability of Green Tea and Coffee Polyphenols

Dietary Supplements Clinical Trial

— POBAS  

Official title:

Bioavailability of Green Tea and Coffee Polyphenols in Healthy Participants

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03248115
• Other study ID #: HNR6480
• Status: Completed
• Phase: N/A
• First received: August 7, 2017
• Last updated: August 16, 2017
• Start date: April 10, 2013
• Est. completion date: October 18, 2013

Study information

• Verified date: August 2017
• Source: MRC Human Nutrition Research
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 11
• Est. completion date: October 18, 2013
• Est. primary completion date: October 18, 2013
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 45 Years

Eligibility

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.

Related Conditions & MeSH terms

• Diet, Food, and Nutrition
• Dietary Supplements

Intervention

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.

Locations

Country	Name	City	State
United Kingdom	MRC HNR Elsie Widdowson Laboratory	Cambridge

Sponsors (1)

Lead Sponsor	Collaborator
MRC Human Nutrition Research

Country where clinical trial is conducted

United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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
Primary	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
Primary	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
Primary	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	Phenolic compounds in tablets	Quantification of the tablet polyphenol content	Through study completion, an average of 3 months