Chronic treatment with a tryptophan-rich protein hydrolysate improves emotional processing, mental energy levels and reaction time in middle-aged women

Br J Nutr. 2015 Jan 28;113(2):350-65. doi: 10.1017/S0007114514003754. Epub 2015 Jan 9.


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.

Keywords: Cognition; Depression; Emotion; LumiVida™; Serotonin; Tryptophan; Well-being.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antidepressive Agents / adverse effects
  • Antidepressive Agents / blood
  • Antidepressive Agents / metabolism
  • Antidepressive Agents / therapeutic use
  • Beverages
  • Cognitive Dysfunction / blood
  • Cognitive Dysfunction / metabolism
  • Cognitive Dysfunction / prevention & control*
  • Cohort Studies
  • Depression / blood
  • Depression / metabolism
  • Depression / prevention & control
  • Dietary Supplements* / adverse effects
  • Double-Blind Method
  • Egg Proteins, Dietary / adverse effects
  • Egg Proteins, Dietary / metabolism
  • Egg Proteins, Dietary / therapeutic use*
  • Energy Metabolism
  • Female
  • Humans
  • Mental Fatigue / blood
  • Mental Fatigue / metabolism
  • Mental Fatigue / prevention & control*
  • Middle Aged
  • Nootropic Agents / adverse effects
  • Nootropic Agents / blood
  • Nootropic Agents / metabolism
  • Nootropic Agents / therapeutic use
  • Protein Hydrolysates / adverse effects
  • Protein Hydrolysates / metabolism
  • Protein Hydrolysates / therapeutic use*
  • Psychiatric Status Rating Scales
  • Reaction Time
  • Serotonin Agents / adverse effects
  • Serotonin Agents / blood
  • Serotonin Agents / metabolism
  • Serotonin Agents / therapeutic use
  • Sleep Wake Disorders / blood
  • Sleep Wake Disorders / metabolism
  • Sleep Wake Disorders / prevention & control
  • Stress, Psychological / blood
  • Stress, Psychological / metabolism
  • Stress, Psychological / prevention & control*
  • Tryptophan / adverse effects
  • Tryptophan / blood
  • Tryptophan / metabolism
  • Tryptophan / therapeutic use*


  • Antidepressive Agents
  • Egg Proteins, Dietary
  • LumiVida
  • Nootropic Agents
  • Protein Hydrolysates
  • Serotonin Agents
  • Tryptophan