Effects of carbohydrates on brain tryptophan availability and stress performance.
Although glucose intake has been associated with enhanced mental performance, this does not follow a clear synchronized relationship and findings are inconsistent. Given the brain's need for glucose during demanding conditions, glucose intake may be beneficial for stress performance. Brain serotonin may be involved as a postprandial mechanism initiated by increases in plasma tryptophan to the sum of the other large neutral amino acids (Trp/LNAA ratio). We tested whether carbohydrate drinks compared to placebo drinks increase the plasma Trp/LNAA ratio and improve stress performance and mood. Thirty-seven healthy subjects were monitored in a double-blind placebo-controlled study for performance when continuously exposed to cold pressor stress; 2h after carbohydrate- or placebo-intake. Cold pressor stress significantly increased cortisol and reduced mood and cognitive performance, whereas carbohydrates significantly increased plasma Trp/LNAA and positively influenced performance and mood under stress.
Markus
C R
CR
Department of Biological Psycholoy & Psychopharmacology, University Maastricht, P.O. Box 6200, MD Maastricht, The Netherlands. R.Markus@psychology.unimaas.nl
D000293:Adolescent; D000328:Adult; D000339:Affect / Q000502:physiology; D000596:Amino Acids / Q000378:metabolism; D001143:Arousal / Q000502:physiology*; D001921:Brain / Q000378:metabolism*; D004040:Dietary Carbohydrates / Q000378:metabolism*; D004311:Double-Blind Method; D005260:Female; D005950:Glucose Solution, Hypertonic / Q000008:administration & dosage; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D008297:Male; D010147:Pain Measurement; D013312:Stress, Physiological / Q000503:physiopathology*; D014364:Tryptophan / Q000378:metabolism*
D000596:Amino Acids; D004040:Dietary Carbohydrates; D005950:Glucose Solution, Hypertonic; D014364:Tryptophan; D006854:Hydrocortisone