Bioavailability of Green Tea and Coffee Polyphenols
- Conditions
- Diet, Food, and NutritionDietary Supplements
- Registration Number
- NCT03248115
- Lead Sponsor
- MRC Human Nutrition Research
- 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.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 11
- Healthy men and women.
- 18-45 years of age.
- BMI between 18.5 and 24.9 kg/m2.
- 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 & Design
- Study Type
- INTERVENTIONAL
- Study Design
- SINGLE_GROUP
- Primary Outcome Measures
Name Time Method Change from baseline phenolic metabolites in urine at 2 weeks 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 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 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 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
- Secondary Outcome Measures
Name Time Method Phenolic compounds in tablets Through study completion, an average of 3 months Quantification of the tablet polyphenol content
Trial Locations
- Locations (1)
MRC HNR Elsie Widdowson Laboratory
🇬🇧Cambridge, United Kingdom