title: Mind the gap-deficits in our knowledge of aspects impacting the bioavailability of phytochemicals and their metabolites--a position paper focusing on carotenoids and polyphenols.
abstract: Various secondary plant metabolites or phytochemicals, including polyphenols and carotenoids, have been associated with a variety of health benefits, such as reduced incidence of type 2 diabetes, cardiovascular diseases, and several types of cancer, most likely due to their involvement in ameliorating inflammation and oxidative stress. However, discrepancies exist between their putative effects when comparing observational and intervention studies, especially when using pure compounds. These discrepancies may in part be explained by differences in intake levels and their bioavailability. Prior to exerting their bioactivity, these compounds must be made bioavailable, and considerable differences may arise due to their matrix release, changes during digestion, uptake, metabolism, and biodistribution, even before considering dose- and host-related factors. Though many insights have been gained on factors affecting secondary plant metabolite bioavailability, many gaps still exist in our knowledge. In this position paper, we highlight several major gaps in our understanding of phytochemical bioavailability, including effects of food processing, changes during digestion, involvement of cellular transporters in influx/efflux through the gastrointestinal epithelium, changes during colonic fermentation, and their phase I and phase II metabolism following absorption.
authors.affiliation: Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology, Belvaux, Luxembourg.
authors.forename: Torsten
authors.initials: T
authors.lastname: Bohn
authors.affiliation: The James Hutton Institute, Invergowrie, Dundee, United Kingdom.
authors.forename: Gordon J
authors.initials: GJ
authors.lastname: McDougall
authors.affiliation: Nutrition and Food Science Area, Faculty of Pharmacy, University of Valencia, Av. Vicente Andrés Estellés s/n, Burjassot, Valencia, Spain.
authors.forename: Amparo
authors.initials: A
authors.lastname: Alegría
authors.affiliation: Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Marie
authors.initials: M
authors.lastname: Alminger
authors.affiliation: Agroscope, Institute for Food Sciences (IFS), Wädenswil, Switzerland.
authors.forename: Eva
authors.initials: E
authors.lastname: Arrigoni
authors.affiliation: VTT Technical Research Centre of Finland, Espoo, Finland.
authors.forename: Anna-Marja
authors.initials: AM
authors.lastname: Aura
authors.affiliation: IBET, Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.|Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Brito
authors.affiliation: Nutrition and Food Science Area, Faculty of Pharmacy, University of Valencia, Av. Vicente Andrés Estellés s/n, Burjassot, Valencia, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Cilla
authors.affiliation: Ege University, Engineering Faculty, Food Engineering Department, Izmir, Turkey.
authors.forename: Sedef N
authors.initials: SN
authors.lastname: El
authors.affiliation: Ege University, Engineering Faculty, Food Engineering Department, Izmir, Turkey.
authors.forename: Sibel
authors.initials: S
authors.lastname: Karakaya
authors.affiliation: Instituto de Investigación en Ciencias de la Alimentación CIAL (CSIC-UAM), Madrid, Spain.
authors.forename: Marie C
authors.initials: MC
authors.lastname: Martínez-Cuesta
authors.affiliation: IBET, Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.|Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: Claudia N
authors.initials: CN
authors.lastname: Santos
mesh_terms: D001682:Biological Availability; D002338:Carotenoids / Q000378:metabolism / Q000493:pharmacokinetics*; D003106:Colon / Q000378:metabolism; D005511:Food Handling; D000069196:Gastrointestinal Microbiome; D006801:Humans; D007408:Intestinal Absorption; D007421:Intestine, Small / Q000378:metabolism / Q000382:microbiology; D064209:Phytochemicals / Q000378:metabolism / Q000493:pharmacokinetics; D059808:Polyphenols / Q000378:metabolism / Q000493:pharmacokinetics*; D012995:Solubility; D014018:Tissue Distribution
chemical_list: D064209:Phytochemicals; D059808:Polyphenols; D002338:Carotenoids
keywords: Biotransformation; Food processing; Microbiota; Mixed diet; Transporters