title: Chronic treatment with a tryptophan-rich protein hydrolysate improves emotional processing, mental energy levels and reaction time in middle-aged women.
abstract: Common pharmacological treatments of mood disorders aim to modulate serotonergic neurotransmission and enhance serotonin levels in the brain. Brain serotonin levels are dependent on the availability of its food-derived precursor essential amino acid tryptophan (Trp). We tested the hypothesis that delivery of Trp via food may serve as an alternative treatment, and examined the effects of a Trp-rich, bioavailable dietary supplement from egg protein hydrolysate on cognitive and emotional functions, mood state, and sleep quality. In a randomised, placebo-controlled, parallel trial, fifty-nine mentally and physically healthy women aged 45-65 years received placebo (n 30) or the supplement (n 29) (both as 0.5 g twice per d) for 19 d. Emotional processing was significantly changed by supplementation, exhibiting a shift in bias away from negative stimuli. The results for the Affective Go/No-Go Task exhibited a slowing of responses to negative words, suggesting reduced attention to negative emotional stimuli. The results for the Facial Emotional Expression Rating Task also supported a shift away from attention to negative emotions and a bias towards happiness. An increase in arousal-like symptoms, labelled 'high energy', shorter reaction times and a slight benefit to sustained attention were observed in the treated subjects. Finally, when the supplement was taken 60-90 min before bedtime, a feeling of happiness before going to bed was consistently reported. In summary, daily consumption of a low-dose supplement containing bioavailable Trp may have beneficial effects on emotional and cognitive functions.
authors.affiliation: DSM Nutritional Products Limited,Wurmisweg 576,CH-4303Kaiseraugst,Switzerland.
authors.forename: M H
authors.initials: MH
authors.lastname: Mohajeri
authors.affiliation: DSM Nutritional Products Limited,Wurmisweg 576,CH-4303Kaiseraugst,Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Wittwer
authors.affiliation: Department of Psychology,Whitelands College, University of Roehampton,Holybourne Avenue,LondonSW15 4JD,UK.
authors.forename: K
authors.initials: K
authors.lastname: Vargas
authors.affiliation: Department of Psychology,Whitelands College, University of Roehampton,Holybourne Avenue,LondonSW15 4JD,UK.
authors.forename: E
authors.initials: E
authors.lastname: Hogan
authors.affiliation: Department of Psychology,Whitelands College, University of Roehampton,Holybourne Avenue,LondonSW15 4JD,UK.
authors.forename: A
authors.initials: A
authors.lastname: Holmes
authors.affiliation: School of Experimental Psychology, University of Bristol,12a, Priory Road,BristolBS8 1TU,UK.
authors.forename: P J
authors.initials: PJ
authors.lastname: Rogers
authors.affiliation: DSM Nutritional Products Limited,Wurmisweg 576,CH-4303Kaiseraugst,Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Goralczyk
authors.affiliation: Department of Psychology,Whitelands College, University of Roehampton,Holybourne Avenue,LondonSW15 4JD,UK.
authors.forename: E L
authors.initials: EL
authors.lastname: Gibson
mesh_terms: D000368:Aged; D000928:Antidepressive Agents / Q000009:adverse effects / Q000097:blood / Q000378:metabolism / Q000627:therapeutic use; D001628:Beverages; D060825:Cognitive Dysfunction / Q000097:blood / Q000378:metabolism / Q000517:prevention & control*; D015331:Cohort Studies; D003863:Depression / Q000097:blood / Q000378:metabolism / Q000517:prevention & control; D019587:Dietary Supplements / Q000009:adverse effects; D004311:Double-Blind Method; D015387:Egg Proteins, Dietary / Q000009:adverse effects / Q000378:metabolism / Q000627:therapeutic use*; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D005222:Mental Fatigue / Q000097:blood / Q000378:metabolism / Q000517:prevention & control*; D008875:Middle Aged; D018697:Nootropic Agents / Q000009:adverse effects / Q000097:blood / Q000378:metabolism / Q000627:therapeutic use; D011492:Protein Hydrolysates / Q000009:adverse effects / Q000378:metabolism / Q000627:therapeutic use*; D011569:Psychiatric Status Rating Scales; D011930:Reaction Time; D018490:Serotonin Agents / Q000009:adverse effects / Q000097:blood / Q000378:metabolism / Q000627:therapeutic use; D012893:Sleep Wake Disorders / Q000097:blood / Q000378:metabolism / Q000517:prevention & control; D013315:Stress, Psychological / Q000097:blood / Q000378:metabolism / Q000517:prevention & control*; D014364:Tryptophan / Q000009:adverse effects / Q000097:blood / Q000378:metabolism / Q000627:therapeutic use*
chemical_list: D000928:Antidepressive Agents; D015387:Egg Proteins, Dietary; C000609744:LumiVida; D018697:Nootropic Agents; D011492:Protein Hydrolysates; D018490:Serotonin Agents; D014364:Tryptophan
keywords: Cognition; Depression; Emotion; LumiVida™; Serotonin; Tryptophan; Well-being