Clinical trial NCT03248115: Bioavailability of Green Tea and Coffee Polyphenols
Official title: Bioavailability of Green Tea and Coffee Polyphenols in Healthy Participants
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Diet, Food, and Nutrition
Dietary Supplements
Keywords: polyphenols
green tea catechins
coffee caffeoylquinic acids
metabolism
inter-individual variability
colonic microbiota
Lead sponsor: MRC Human Nutrition Research
Sponsor class: OTHER_GOV
First posted: 2017-08-14
Enrollment: 11
Sex: ALL
Minimum age (years): 18
Maximum age (years): 45
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: BASIC_SCIENCE

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.


Eligibility 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.

Primary outcomes:
measure: Change from baseline phenolic metabolites in urine at 2 weeks
timeFrame: Week 0 -before supplementation- and week 2
measure: Change from baseline phenolic metabolites in urine at 4 weeks
timeFrame: Week 0 -before supplementation- and week 4
measure: Change from baseline phenolic metabolites in urine at 8 weeks
timeFrame: Week 0 -before supplementation- and week 8
measure: Change from baseline phenolic metabolites in urine at 12 weeks
timeFrame: Week 0 -before supplementation- and week 12 -4 weeks after finishing the supplementation period-
Secondary outcomes:
measure: Phenolic compounds in tablets
timeFrame: Through study completion, an average of 3 months
Other outcomes:
Locations:
city: Cambridge
country: United Kingdom
facility: MRC HNR Elsie Widdowson Laboratory
Study officials:
affiliation: MRC HNR
name: Virginia Tomatis, PhD
role: PRINCIPAL_INVESTIGATOR
References: