Bioavailability of Green Tea and Coffee Polyphenols (POBAS)

MRC Human Nutrition Research

Status

Completed

Conditions

Diet, Food, and Nutrition

Dietary Supplements

Treatments

Dietary Supplement: Green tea and green coffee extract tablets

Study type

Interventional

Funder types

Other

Identifiers

NCT03248115

HNR6480

Details and patient eligibility

About

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.

Enrollment

11 patients

Sex

All

Ages

18 to 45 years old

Volunteers

Accepts Healthy Volunteers

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.