title: Assessment of the effect of high or low protein diet on the human urine metabolome as measured by NMR.
abstract: The objective of this study was to identify urinary metabolite profiles that discriminate between high and low intake of dietary protein during a dietary intervention. Seventy-seven overweight, non-diabetic subjects followed an 8-week low-calorie diet (LCD) and were then randomly assigned to a high (HP) or low (LP) protein diet for 6 months. Twenty-four hours urine samples were collected at baseline (prior to the 8-week LCD) and after dietary intervention; at months 1, 3 and 6, respectively. Metabolite profiling was performed by (1)H NMR and chemometrics. Using partial least squares regression (PLS), it was possible to develop excellent prediction models for urinary nitrogen (root mean square error of cross validation (RMSECV) = 1.63 mmol/L; r = 0.89) and urinary creatinine (RMSECV = 0.66 mmol/L; r = 0.98). The obtained high correlations firmly establish the validity of the metabolomic approach since urinary nitrogen is a well established biomarker for daily protein consumption. The models showed that trimethylamine-N-oxide (TMAO) is correlated to urinary nitrogen. Furthermore, urinary creatine was found to be increased by the HP diet whereas citric acid was increased by the LP diet. Despite large variations in individual dietary intake, differentiated metabolite profiles were observed at the dietary group-level.
authors.affiliation: Department of Human Nutrition, Faculty of Life Sciences, University of Copenhagen, DK-1958 Frederiksberg, Denmark.
authors.forename: Lone G
authors.initials: LG
authors.lastname: Rasmussen
authors.affiliation: Foss Analytical A/S, DK-3400 Hillerød, Denmark.
authors.forename: Hanne
authors.initials: H
authors.lastname: Winning
authors.affiliation: Quality and Technology, Department of Food Science, Faculty of Life Sciences, University of Copenhagen, DK-1958 Frederiksberg, Denmark.
authors.forename: Francesco
authors.initials: F
authors.lastname: Savorani
authors.affiliation: Foss Analytical A/S, DK-3400 Hillerød, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Toft
authors.affiliation: Department of Human Nutrition, Faculty of Life Sciences, University of Copenhagen, DK-1958 Frederiksberg, Denmark.
authors.forename: Thomas M
authors.identifier: 0000-0001-7621-3131
authors.initials: TM
authors.lastname: Larsen
authors.affiliation: Department of Human Nutrition, Faculty of Life Sciences, University of Copenhagen, DK-1958 Frederiksberg, Denmark.
authors.forename: Lars O
authors.initials: LO
authors.lastname: Dragsted
authors.affiliation: Department of Human Nutrition, Faculty of Life Sciences, University of Copenhagen, DK-1958 Frederiksberg, Denmark.
authors.forename: Arne
authors.initials: A
authors.lastname: Astrup
authors.affiliation: Quality and Technology, Department of Food Science, Faculty of Life Sciences, University of Copenhagen, DK-1958 Frederiksberg, Denmark.
authors.forename: Søren B
authors.initials: SB
authors.lastname: Engelsen
mesh_terms: D000328:Adult; D019343:Citric Acid / Q000652:urine; D003404:Creatinine / Q000652:urine; D018753:Diet, Protein-Restricted; D004044:Dietary Proteins / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D055432:Metabolomics; D008875:Middle Aged; D009584:Nitrogen / Q000652:urine; D009765:Obesity / Q000178:diet therapy*; D014556:Urine / Q000737:chemistry*
chemical_list: D004044:Dietary Proteins; D019343:Citric Acid; D003404:Creatinine; D009584:Nitrogen