CPT and health: Understanding the biological effects of dietary complex phenols and tannins and their implications for the customer's health and well-being

• Research unit: EU RFP
• Project number: 95.0216

Key words (English)

Polyphenols; mineral bioavailability

Alternative project number (English)

EU project number: FAIR-CT95-0653

Research programs (English)

EU-programme: 4. Frame Research Programme - 4.3 Biomedical/Health research

Short description (English)

See abstract

Further information (English)

Full name of research-institution/enterprise:
ETH Zürich
Institut of Food Science and Nutrition
Human Nutrition Laboratory

Partners and International Organizations (English)

University of Surrey (UK), INRA (F), University of Sala-manca (E), University of Florence (I), AFRC (UK), Rijksinstitut voor Volksgezundheid en Milieuhygiene (NL)

Abstract (English)

A series of studies has been conducted in order to investigate the influence of red wine and black tea on copper and zinc absorption from the diet. Both red wine and black tea contain significant amounts of polyphenols which may inhibit absorption of copper and zinc in the intestine by complex formation. To determine copper and zinc absorption in vivo, the elements can be labeled extrinsically in the test meals using highly enriched stable isotopes (65Cu and 70Zn). By this approach, apparent copper and zinc absorption can be determined by quantifying the amount of isotopic label excreted in feces following test meal consumption.
Each of the 10 subjects participating in the study received three different test meals under strictly standardized conditions. Test meals consisted of a white wheat bread roll (75 g) served together with red wine (200 ml), black tea (200 ml) and 200 ml of water in the reference meal, respectively. Total polyphenol content (Folin-Ciocalteau) in black tea and red wine was equilibrated to 200 mg. The black tea as well as the red wine administered were obtained from the collaborative partners of the project who based their investigations on the same (black tea) or similar (red wine, different harvest) material. The separate test meals were allocated to each subject in a randomized order and served under strictly standardized conditions with a time lapse of 2-4 weeks in between. Quantitative recovery of isotopic labels in feces was accomplished by collecting feces quantitatively using a dye-technique to define the collection period (6 day fecal pooling). Urine was collected in parallel to investigate if phenolic compounds are absorbed and excreted still combined with the minerals.
All subjects completed each of the three separate studies. To quantify the amount of isotopic label present in the feces material, a sample mineralization technique was developed which allowed representative subsampling of highly inhomogenous feces material. After separation of copper and zinc from the mineralized matrix using anion-exchange chromatography, copper and zinc isotopic ratios were determined by thermal ionization mass spectrometry using the recently developed/installed techniques. Isotopic analysis of collected feces and data evaluation will be completed in early summer '99.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 95.0216