Measuring exposure to the polyphenol metabolome in observational epidemiologic studies: current tools and applications and their limits.
Much experimental evidence supports a protective role of dietary polyphenols against chronic diseases such as cardiovascular diseases, diabetes, and cancer. However, results from observational epidemiologic studies are still limited and are often inconsistent. This is largely explained by the difficulties encountered in the estimation of exposure to the polyphenol metabolome, which is composed of ~500 polyphenols distributed across a wide variety of foods and characterized by diverse biological properties. Exposure to the polyphenol metabolome in epidemiologic studies can be assessed by the use of detailed dietary questionnaires or the measurement of biomarkers of polyphenol intake. The questionnaire approach has been greatly facilitated by the use of new databases on polyphenol composition but is limited by bias as a result of self-reporting. The use of polyphenol biomarkers holds much promise for objective estimation of polyphenol exposure in future metabolome-wide association studies. These approaches are reviewed and their advantages and limitations discussed by using examples of epidemiologic studies on polyphenols and cancer. The current improvement in these techniques, along with greater emphasis on the intake of individual polyphenols rather than polyphenols considered collectively, will help unravel the role of these major food bioactive constituents in disease prevention.
From the Section of Nutrition and Metabolism, International Agency for Research on Cancer, Lyon, France (RZ-R, JAR, IR, and AS); the Unit of Nutrition, Environment, and Cancer, Catalan Institute of Oncology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain (RZ-R); and the Cancer and Environment Unit, Centre Léon Bérard, Lyon, France (MT).
Raul
R
Zamora-Ros
From the Section of Nutrition and Metabolism, International Agency for Research on Cancer, Lyon, France (RZ-R, JAR, IR, and AS); the Unit of Nutrition, Environment, and Cancer, Catalan Institute of Oncology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain (RZ-R); and the Cancer and Environment Unit, Centre Léon Bérard, Lyon, France (MT).
Marina
M
Touillaud
From the Section of Nutrition and Metabolism, International Agency for Research on Cancer, Lyon, France (RZ-R, JAR, IR, and AS); the Unit of Nutrition, Environment, and Cancer, Catalan Institute of Oncology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain (RZ-R); and the Cancer and Environment Unit, Centre Léon Bérard, Lyon, France (MT).
Joseph A
JA
Rothwell
From the Section of Nutrition and Metabolism, International Agency for Research on Cancer, Lyon, France (RZ-R, JAR, IR, and AS); the Unit of Nutrition, Environment, and Cancer, Catalan Institute of Oncology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain (RZ-R); and the Cancer and Environment Unit, Centre Léon Bérard, Lyon, France (MT).
Isabelle
I
Romieu
From the Section of Nutrition and Metabolism, International Agency for Research on Cancer, Lyon, France (RZ-R, JAR, IR, and AS); the Unit of Nutrition, Environment, and Cancer, Catalan Institute of Oncology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain (RZ-R); and the Cancer and Environment Unit, Centre Léon Bérard, Lyon, France (MT).
Augustin
A
Scalbert
D001682:Biological Availability; D015415:Biomarkers / Q000097:blood; D016208:Databases, Factual; D016021:Epidemiologic Studies; D006801:Humans; D055442:Metabolome / Q000187:drug effects*; D009369:Neoplasms / Q000517:prevention & control; D015596:Nutrition Assessment; D064887:Observational Studies as Topic; D059808:Polyphenols / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires
D015415:Biomarkers; D059808:Polyphenols