Whey protein rich in α-lactalbumin increases the ratio of plasma tryptophan to the sum of the other large neutral amino acids and improves cognitive performance in stress-vulnerable subjects
| Autor: | C. Rob Markus, Edward H F de Haan, Berend Olivier |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Adult
Male Serotonin medicine.medical_specialty Whey protein Adolescent Medicine (miscellaneous) Biology Serotonergic chemistry.chemical_compound Cognition Double-Blind Method Memory Stress Physiological Internal medicine medicine Humans Chronic stress Amino Acids Neurotransmitter Lactalbumin Cross-Over Studies Nutrition and Dietetics Tryptophan Caseins Milk Proteins Crossover study Whey Proteins Endocrinology chemistry Female |
| Zdroj: | The American Journal of Clinical Nutrition. 75:1051-1056 |
| ISSN: | 0002-9165 |
| Popis: | Background: Cognitive performance often declines under chronic stress exposure. The negative effect of chronic stress on performance may be mediated by reduced brain serotonin function. The uptake of the serotonin precursor tryptophan into the brain depends on nutrients that influence the availability of tryptophan by changing the ratio of plasma tryptophan to the sum of the other large neutral amino acids (Trp-LNAA ratio). In addition, a diet-induced increase in tryptophan may increase brain serotonergic activity levels and improve cognitive performance, particularly in high stress-vulnerable subjects. Objective: We tested whether alpha-lactalbumin, a whey protein with a high tryptophan content, would increase the plasma Trp-LNAA ratio and improve cognitive performance in high stress- vulnerable subjects. Design: Twenty-three high stress-vulnerable subjects and 29 low stress-vulnerable subjects participated in a double-blind, placebo-controlled, crossover study. All subjects conducted a memory-scanning task after the intake of a diet enriched with either alpha-lactalbumin (alpha-lactalbumin diet) or sodium caseinate (control diet). Blood samples were taken to measure the effect of dietary manipulation on the plasma Trp-LNAA ratio. Results: A significantly greater increase in the plasma Trp-LNAA ratio after consumption of the alpha-lactalbumin diet than after the control diet (P = 0.0001) was observed; memory scanning improved significantly only in the high stress-vulnerable subjects (P = 0.019). Conclusion: Because an increase in the plasma Trp-LNAA ratio is considered to be an indirect indication of increased brain serotonin function, the results suggest that dietary protein rich in alpha-lactalbumin improves cognitive performance in stress-vulnerable subjects via increased brain tryptophan and serotonin activities. |
| Databáze: | OpenAIRE |
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