Print Email Facebook Twitter Evening intake of α-lactalbumin increases plasma tryptophan availability and improves morning alertness and brain measures of attention Title Evening intake of α-lactalbumin increases plasma tryptophan availability and improves morning alertness and brain measures of attention Author Markus, C.R. Jonkman, L.M. Lammers, J.H.C.M. Deutz, N.E.P. Messer, M.H. Rigtering, N. TNO Kwaliteit van Leven TNO Voeding Publication year 2005 Abstract Background: Brain serotonin function is thought to promote sleep regulation and cognitive processes, whereas sleep abnormalities and subsequent behavioral decline are often attributed to deficient brain serotonin activity. Brain uptake of the serotonin precursor tryptophan is dependent on nutrients that influence the availability of tryptophan via a change in the ratio of plasma tryptophan to the sum of the other large neutral amino acids (Trp:LNAA). Objective: We tested whether evening consumption of α-lactalbumin protein with an enriched tryptophan content of 4.8 g/100 g increases plasma Trp:LNAA and improves alertness and performance on the morning after sleep, particularly in subjects with sleep complaints. Design: Healthy subjects with (n = 14) or without (n = 14) mild sleep complaints participated in a double-blind, placebo-controlled study. The subjects slept at the laboratory for 2 separate nights so that morning performance could be evaluated after an evening diet containing either tryptophan-rich α-lactalbumin or tryptophan-low placebo protein. Evening dietary changes in plasma Trp:LNAA were measured. Behavioral (reaction time and errors) and brain measures of attention were recorded during a continuous performance task. Results: Evening α-lactalbumin intake caused a 130% increase in Trp:LNAA before bedtime (P = 0.0001) and modestly but significantly reduced sleepiness (P = 0.013) and improved brain-sustained attention processes (P = 0.002) the following morning. Only in poor sleepers was this accompanied by improved behavioral performance (P = 0.05). Conclusion: Evening dietary increases in plasma tryptophan availability for uptake into the brain enhance sustained alertness early in the morning after an overnight sleep, most likely because of improved sleep. © 2005 American Society for Clinical Nutrition. Subject Biology ToxicologyToxicology and Applied Pharmacologyα-lactalbuminAttentionContinuous performance taskEvent-related brain acivitySleep complaintsTryptophanAlpha lactalbuminPlaceboTryptophanAmino acidLactalbuminAdultAlertnessBrain functionClinical trialControlled clinical trialControlled studyDietDouble blind procedureDrug effectFemaleHumanMaleReaction timeSomnolenceTask performanceAnalysis of varianceBloodBrainElectroencephalographyMetabolismPsychomotor performanceSleepTimeAdultAmino AcidsAnalysis of VarianceBrainDouble-Blind MethodElectroencephalographyFemaleHumansLactalbuminMalePsychomotor PerformanceSleepTime FactorsTryptophan To reference this document use: http://resolver.tudelft.nl/uuid:521d12e1-d5a1-4478-a1af-1670f366f82c TNO identifier 239025 ISSN 0002-9165 Source American Journal of Clinical Nutrition, 81 (5), 1026-1033 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.