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
Open accessAbstract
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.
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α-lactalbumin contains an ample supply of tryptophan which increases cognitive performance under stress.
“In addition, α-lactalbumin contains an ample supply of tryptophan which increases cognitive performance under stress [172]”
From International Society of Sports Nutrition Position Stand: protein and exercise (2017) · cites this paper as [172]
α-lactalbumin contains tryptophan which improves the quality of sleep.
“improves the quality of sleep [172, 173]”
From International Society of Sports Nutrition Position Stand: protein and exercise (2017) · cites this paper as [172]
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International Society of Sports Nutrition Position Stand: protein and exercise
Jäger, R., Kerksick, C. M., Campbell, B. I., Cribb, P. J., Wells, S. D., Skwiat, T. M., Purpura, M., Ziegenfuss, T. N., Ferrando, A. A., Arent, S. M., et al. (2017) · Journal of the International Society of Sports Nutrition · doi:10.1186/s12970-017-0177-8 · Cited by 873 · see citing works
“In addition, α-lactalbumin contains an ample supply of tryptophan which increases cognitive performance under stress [172], improves the quality of sleep [172, 173], and may also speed wound healing [172], properties which could be vital for recovery from combat and contact sporting events.”
BackgroundInternational Society of Sports Nutrition position stand: protein and exercise
Campbell, B., Kreider, R. B., Ziegenfuss, T., La Bounty, P., Roberts, M., Burke, D., Landis, J., Lopez, H., & Antonio, J. (2007) · Journal of the International Society of Sports Nutrition · doi:10.1186/1550-2783-4-8 · Cited by 716 · see citing works
Dietary protein, weight loss, and weight maintenance
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Escitalopram and Enhancement of Cognitive Recovery Following Stroke
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Milk proteins as a source of tryptophan-containing bioactive peptides
Nongonierma, A. B., & FitzGerald, R. J. (2015) · Food & Function · doi:10.1039/c5fo00407a · Cited by 83 · see citing works
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Self-citation
- Authors
- Markus, C. R., Olivier, B., & de Haan, E. H.
- Affiliations
- Utrecht University (NL)
- Corresponding author
- Markus, C Rob
- ORCID
- Olivier, Berend
- Venue
- The American Journal of Clinical Nutrition
- Publisher
- Elsevier BV
- Published
- 2002-06
- Volume
- 75
- Issue
- 6
- Pages
- 1051-1056
- ISSN
- 0002-9165 (ISSN-L)
- OpenAlex
- W2138144859
- Cited by
- 230
- References
- 1
- Citations by year
- 2026: 6 · 2025: 10 · 2024: 11 · 2023: 9 · 2022: 7 · 2021: 8 · 2020: 12 · 2019: 12 · 2018: 15 · 2017: 10 · 2016: 5 · 2015: 8 · 2014: 11 · 2013: 19 · 2012: 2
- FWCI
- 2.27
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Licence
- Locations
- American Journal of Clinical Nutrition (publishedVersion)
- PubMed (publishedVersion)
- Radboud Repository (Radboud University) (submittedVersion)
- Topics
- Life Sciences › Neuroscience › Biological Psychiatry › Tryptophan and brain disorders
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Protein Hydrolysis and Bioactive Peptides
- Health Sciences › Nursing › Nutrition and Dietetics › Fatty Acid Research and Health
- Keywords
- alpha-lactalbumin, whey protein, plasma amino acids, brain serotonin, cognitive performance, chronic stress, stress vulnerability, memory scanning, sodium caseinate, dietary protein
- MeSH terms
- Whey Proteins, Adolescent, Adult, Amino Acids, Caseins, Cognition, Double-Blind Method, Female, Humans, Lactalbumin, Male, Memory, Milk Proteins, Serotonin, Stress, Physiological, Tryptophan, Cross-Over Studies
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