title: Assessment of the efficacy of functional food ingredients-introducing the concept "kinetics of biomarkers".
abstract: Functional foods are "foods and beverages with claimed health benefits based on scientific evidence". Health claims need to be substantiated scientifically. The future of functional foods will heavily rely on proven efficacy in well-controlled intervention studies with human volunteers. In order to have the maximum output of human trials, improvements are needed with respect to study design and optimization of study protocols. Efficacy at realistic intake levels needs to be established in studies with humans via the use of suitable biomarkers, unless the endpoint can be measured directly. The human body is able to deal with chemical entities irrespective of their origin, and the pharmaceutical terms "absorption, distribution, metabolism and excretion" have their equivalent when biomarkers are concerned. Whereas only "diurnal variation" or "circadian rhythm" is sometimes considered, little attention is paid to "kinetics of biomarkers". "Kinetics of biomarkers" comprises "formation, distribution, metabolism and excretion". However, this is at present neither an established science nor common practice in nutrition research on functional foods. As a consequence, sampling times and matrices, for example, are chosen on the basis of historical practice and convenience (for volunteers and scientists) but not on the basis of in depth insight. The concept of kinetics of biomarkers is illustrated by a variety of readily comprehensible examples, such as malaria, cholesterol, polyphenols, glutathione-S-transferase alpha, F2-isoprostanes, interleukin-6, and plasma triacylglycerides.
authors.affiliation: Unilever Health Institute, P.O. Box 114, 3130 AC, Vlaardingen, The Netherlands. hans.verhagen@unilever.com
authors.forename: Hans
authors.initials: H
authors.lastname: Verhagen
authors.forename: Stefan
authors.initials: S
authors.lastname: Coolen
authors.forename: Guus
authors.initials: G
authors.lastname: Duchateau
authors.forename: Mark
authors.initials: M
authors.lastname: Hamer
authors.forename: Janet
authors.initials: J
authors.lastname: Kyle
authors.forename: Andreas
authors.initials: A
authors.lastname: Rechner
mesh_terms: D015415:Biomarkers; D005502:Food; D005515:Food Labeling; D058870:Food, Organic; D006801:Humans; D007700:Kinetics; D009753:Nutritive Value; D012107:Research Design
chemical_list: D015415:Biomarkers