Intake of tryptophan-enriched whey protein acutely enhances recall of positive loaded words in patients with multiple sclerosis.
Multiple sclerosis (MS) has physiological and/or immunological characteristics that diminish serotonin metabolism, a neurotransmitter associated with affective and cognitive functions. The aim was examine the acute and dose-dependent effects of a dietary tryptophan (TRP) enrichment on affective and cognitive functions in MS patients. We hypothesized that increased dietary availability of the amino acid TRP enhances serotonin concentrations and improves neuropsychological functions.



In a double-blind, placebo-controlled, crossover study, MS patients with (n = 15) and without (n = 17) depressed mood ingested a whey protein mixture with 4 different amounts of TRP. Mood states, total plasma TRP and plasma TRP/ΣLNAA ratio were measured during each test session and cognitive tasks were conducted three hours after dietary intake.



A fast, transient and dose-dependent increase of total plasma TRP and TRP/ΣLNAA ratio was found. Ratings of negative mood decreased over time, independent of the TRP dose. Relative to whey-only, immediate word recall and delayed recognition improved after ingestion of the lowest added TRP dose and was mainly due to better recollection for positive loaded words. Executive functions were not affected by a difference in TRP availability.



A moderate addition of TRP to whey protein enhances memory processes without improving the mood state in MS. ccmo-registration number is NL32316.096.10.
Academic MS Center Limburg, Zuyderland Medical Center, Sittard, The Netherlands; Center for Translational Research in Aging & Longevity, Department of Health & Kinesiology, Texas A&M University, USA. Electronic address: ck.lieben@ctral.org.
Cindy K
CK
Lieben
Faculty of Psychology and Neuroscience, Department of Neuropsychology & Psychopharmacology, Maastricht University, The Netherlands.
Arjan
A
Blokland
Center for Translational Research in Aging & Longevity, Department of Health & Kinesiology, Texas A&M University, USA.
Nicolaas E
NE
Deutz
Faculty of Psychology and Neuroscience, Department of Neuropsychology & Psychopharmacology, Maastricht University, The Netherlands.
Willemijn
W
Jansen
Department of Epidemiology & Biostatistics, School of Public Health, Texas A&M University, USA.
Gang
G
Han
Academic MS Center Limburg, Zuyderland Medical Center, Sittard, The Netherlands; Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, The Netherlands.
Raymond M
RM
Hupperts
D000328:Adult; D000339:Affect / Q000187:drug effects; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000187:drug effects*; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000178:diet therapy* / Q000503:physiopathology; D011581:Psychological Tests; D021641:Recognition, Psychology / Q000187:drug effects; D014364:Tryptophan / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D000067816:Whey Proteins / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use
D000067816:Whey Proteins; D014364:Tryptophan
Cognition; Hydrolyzed whey protein; Mood; Multiple sclerosis; Tryptophan enrichment