title: The usefulness of in vitro models to predict the bioavailability of iron and zinc: a consensus statement from the HarvestPlus expert consultation.
abstract: A combination of dietary and host-related factors determines iron and zinc absorption, and several in vitro methods have been developed as preliminary screening tools for assessing bioavailability. An expert committee has reviewed evidence for their usefulness and reached a consensus. Dialyzability (with and without simulated digestion) gives some useful information but cannot predict the correct magnitude of response and may sometimes predict the wrong direction of response. Caco-2 cell systems (with and without simulated digestion) have been developed for iron availability, but the magnitude of different effects does not always agree with results obtained in human volunteers, and the data for zinc are too limited to draw conclusions about the validity of the method. Caco-2 methodologies vary significantly between laboratories and require experienced technicians and good quality cell culture facilities to obtain reproducible results. Algorithms can provide semi-quantitative information enabling diets to be classified as high, moderate, or low bioavailability. While in vitro methods can be used to generate ideas and develop hypotheses, they cannot be used alone for important decisions concerning food fortification policy, selection of varieties for plant breeding programs, or for new product development in the food industry. Ultimately human studies are required for such determinations.
authors.affiliation: Institute of Food Research, Norwich Research Park, Norfolk, UK. sue.fairweather-tait@bbsrc.ac.uk
authors.forename: Sue
authors.initials: S
authors.lastname: Fairweather-Tait
authors.forename: Sean
authors.initials: S
authors.lastname: Lynch
authors.forename: Christine
authors.initials: C
authors.lastname: Hotz
authors.forename: Richard
authors.initials: R
authors.lastname: Hurrell
authors.forename: Leo
authors.initials: L
authors.lastname: Abrahamse
authors.forename: Steve
authors.initials: S
authors.lastname: Beebe
authors.forename: Stine
authors.initials: S
authors.lastname: Bering
authors.forename: Klaus
authors.initials: K
authors.lastname: Bukhave
authors.forename: Ray
authors.initials: R
authors.lastname: Glahn
authors.forename: Michael
authors.initials: M
authors.lastname: Hambidge
authors.forename: Janet
authors.initials: J
authors.lastname: Hunt
authors.forename: Bo
authors.initials: B
authors.lastname: Lonnerdal
authors.forename: Denis
authors.initials: D
authors.lastname: Miller
authors.forename: Najat
authors.initials: N
authors.lastname: Mohktar
authors.forename: Penelope
authors.initials: P
authors.lastname: Nestel
authors.forename: Manju
authors.initials: M
authors.lastname: Reddy
authors.forename: Ann-Sofie
authors.initials: AS
authors.lastname: Sandber
authors.forename: Paul
authors.initials: P
authors.lastname: Sharp
authors.forename: Birgit
authors.initials: B
authors.lastname: Teucher
authors.forename: Trinidad P
authors.initials: TP
authors.lastname: Trinidad
mesh_terms: D001682:Biological Availability; D018938:Caco-2 Cells; D006801:Humans; D007501:Iron / Q000378:metabolism / Q000493:pharmacokinetics*; D015032:Zinc / Q000378:metabolism / Q000493:pharmacokinetics*
chemical_list: D007501:Iron; D015032:Zinc