title: Alkylresorcinol metabolites in urine correlate with the intake of whole grains and cereal fibre in free-living Swedish adults.
abstract: Alkylresorcinols (AR) have been established as short/medium-term biomarkers for whole grain (WG) wheat and rye intake; and AR metabolites, 3,5-dihydroxybenzoic acid and 3-(3,5-dihydroxyphenyl)-propanoic acid, have been suggested as complementary biomarkers to AR. The present study examined the medium-term reproducibility and relative validity of urinary AR metabolites as biomarkers for WG and cereal fibre intake. A total of sixty-six free-living Swedes completed 3 d weighed food records and provided single 24 h urine collections and morning urine spot samples on two occasions, 2-3 months apart. The medium-term reproducibility of urinary AR metabolites was moderate when assessed in 24 h collections and lower in creatinine (CR)-adjusted morning urine. Mean AR metabolite 24 h excretions correlated well with total WG (r(s) 0·31-0·52, P < 0·05) and cereal fibre (r(s) 0·46-0·58, P < 0·001) intake on both occasions. As expected, correlations with WG (r(s) 0·28-0·38, P < 0·05) and cereal fibre (r(s) 0·35-0·42, P < 0·01) were weaker for mean CR-adjusted AR metabolite concentrations in spot samples of morning urine, although the adjusted concentrations correlated well with 24 h urinary excretion (r(s) 0·69-0·73, P < 0·001). Adjustment for intra-individual variations substantially improved the correlations between intake and excretion. These findings suggest that urinary AR metabolites can successfully reflect the medium-term intake of WG and cereal fibre when adjusted for intra-individual variation in this population, where rye was the major contributor to high WG intake. The performance of urinary AR metabolites as medium-term biomarkers appears to be comparable to that of fasting plasma AR concentration in this population.
authors.affiliation: Department of Food Science, Swedish University of Agricultural Sciences, Box 7051, SE-750 07 Uppsala, Sweden. matti.marklund@slu.se
authors.forename: Matti
authors.initials: M
authors.lastname: Marklund
authors.forename: Rikard
authors.initials: R
authors.lastname: Landberg
authors.forename: Agneta
authors.initials: A
authors.lastname: Andersson
authors.forename: Per
authors.initials: P
authors.lastname: Åman
authors.forename: Afaf
authors.initials: A
authors.lastname: Kamal-Eldin
mesh_terms: D000328:Adult; D000465:Algorithms; D000478:Alkylation; D015415:Biomarkers / Q000652:urine; D003404:Creatinine / Q000652:urine; D015930:Diet Records; D004043:Dietary Fiber / Q000008:administration & dosage / Q000378:metabolism*; D002523:Edible Grain / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D005511:Food Handling; D006801:Humans; D062385:Hydroxybenzoates / Q000378:metabolism / Q000652:urine; D008297:Male; D008875:Middle Aged; D010636:Phenols / Q000378:metabolism / Q000652:urine; D010666:Phenylpropionates; D011422:Propionates / Q000378:metabolism / Q000652:urine; D015203:Reproducibility of Results; D012118:Resorcinols / Q000378:metabolism / Q000652:urine*; D012434:Secale / Q000737:chemistry; D013548:Sweden; D013997:Time Factors
chemical_list: C532605:3-(3,5-dihydroxyphenyl)-1-propanoic acid; D015415:Biomarkers; D004043:Dietary Fiber; D062385:Hydroxybenzoates; D010636:Phenols; D010666:Phenylpropionates; D011422:Propionates; D012118:Resorcinols; D003404:Creatinine