Dietary tryptophan-rich protein hydrolysate can acutely impact physiological and psychological measures of mood and stress in healthy adults.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 35343881 · doi:10.1080/1028415X.2022.2047435
What was done
Researchers conducted a double-blind, randomized, controlled parallel-group trial in 45 healthy adults across three arms to assess the acute effects of low-dose egg protein hydrolysate (EPH; 0.5 g, 1.0 g, or a reference control in a food matrix). After ingestion, participants underwent a multi-task cognitive stressor. Measured outcomes included blood tryptophan bioavailability biomarkers, self-reported mood states, attentional task performance, autonomic parameters (heart rate variability), and electroencephalographic (EEG) emotional reactivity.
What was found
The abstract reports directional findings without numerical values, confidence intervals, or p-values. Relative to reference control, the 1.0 g dose increased tryptophan bioavailability from baseline. Both 0.5 g and 1.0 g doses improved heart rate variability parameters related to parasympathetic activation and altered late neural responses to negative versus neutral emotions on EEG. Post-hoc analyses showed baseline gender differences in tryptophan bioavailability and suggested mood rating changes depended on an interaction between gender and changes in tryptophan bioavailability.
Why it matters
This study provides preliminary evidence that egg protein hydrolysate at lower dietary doses (0.5–1.0 g) within a food matrix can acutely modulate autonomic stress responses and neural emotional reactivity.
Limits
The sample size was small (45 participants across three parallel arms, approximately 15 per group). The abstract reports no numerical data or effect sizes. Mood findings relied on exploratory post-hoc subgroup interaction analyses, and only acute effects following a single laboratory stressor were evaluated in healthy participants.
Cited by
- supports Dietary tryptophan provided by protein serves as a precursor molecule for the synthesis of the neurotransmitter serotonin.