title: Evaluation of acute tryptophan depletion and sham depletion with a gelatin-based collagen peptide protein mixture.
abstract: Acute Tryptophan Depletion (ATD) is a dietary method used to modulate central 5-HT to study the effects of temporarily reduced 5-HT synthesis. The aim of this study is to evaluate a novel method of ATD using a gelatin-based collagen peptide (CP) mixture. We administered CP-Trp or CP+Trp mixtures to 29 healthy volunteers; 13 from a randomized, double-blinded crossover study and sixteen from a randomized, double-blinded study run in our laboratory. Plasma amino acids, mood, side effects, cortisol concentrations, mean arterial blood pressure and heart rate were measured at multiple time-points. Repeated measures analysis of variance and Wilcoxon or Mann-Whitney U non-parametric tests were used to analyze the effects of intervention. Intake of the CP-Trp mixture efficiently reduced plasma Trp; however, the CP+Trp mixture induced a large significant increase in plasma Trp. No other significant effects of CP-Trp compared to CP+Trp were observed. The transient increase in plasma Trp after CP+Trp may impair comparison to the CP-Trp and we therefore recommend in future studies to use a smaller dose of Trp supplement to the CP mixture.
authors.affiliation: Center for Integrated Molecular Brain Imaging & Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark; Faculty of Health and Medical Science, University of Copenhagen, Denmark. Electronic address: dea@nru.dk.
authors.forename: D S
authors.initials: DS
authors.lastname: Stenbæk
authors.affiliation: Center for Integrated Molecular Brain Imaging & Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark; Faculty of Health and Medical Science, University of Copenhagen, Denmark.
authors.forename: H S
authors.initials: HS
authors.lastname: Einarsdottir
authors.affiliation: Center for Integrated Molecular Brain Imaging & Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark.
authors.forename: T
authors.initials: T
authors.lastname: Goregliad-Fjaellingsdal
authors.affiliation: Center for Integrated Molecular Brain Imaging & Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark; Faculty of Health and Medical Science, University of Copenhagen, Denmark.
authors.forename: G M
authors.initials: GM
authors.lastname: Knudsen
authors.affiliation: Center for Integrated Molecular Brain Imaging & Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark.
authors.forename: V G
authors.initials: VG
authors.lastname: Frokjaer
authors.affiliation: Center for Integrated Molecular Brain Imaging & Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark; Faculty of Health and Medical Science, University of Copenhagen, Denmark; Danish Dementia Research Centre, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark.
authors.forename: S G
authors.initials: SG
authors.lastname: Hasselbalch
mesh_terms: D000293:Adolescent; D000328:Adult; D000339:Affect; D000704:Analysis of Variance; D003094:Collagen; D018592:Cross-Over Studies; D004032:Diet; D004311:Double-Blind Method; D005260:Female; D005780:Gelatin; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D008297:Male; D016896:Treatment Outcome; D014364:Tryptophan / Q000008:administration & dosage / Q000097:blood*; D055815:Young Adult
chemical_list: D014364:Tryptophan; D005780:Gelatin; D003094:Collagen; D006854:Hydrocortisone