Chronic treatment with a tryptophan-rich protein hydrolysate improves emotional processing, mental energy levels and reaction time in middle-aged women.
Level 2 - randomized trial
Randomized, placebo-controlled, parallel-group clinical trial
PubMed 25572038 · doi:10.1017/S0007114514003754
What was done
Fifty-nine healthy women aged 45–65 were randomized to receive either a tryptophan-rich egg protein hydrolysate supplement (n = 29) or a placebo (n = 30) at a dose of 0.5 g twice daily for 19 days in a parallel-group trial. Cognitive function, emotional processing (evaluated via an Affective Go/No-Go Task and a Facial Emotional Expression Rating Task), mood state, and sleep quality were measured.
What was found
The abstract reports no exact numerical values, effect sizes, or p-values. It reports that tryptophan supplementation significantly shifted emotional processing away from negative stimuli, slowed responses to negative words on the Affective Go/No-Go Task, and biased facial expression ratings toward happiness. Treated participants also experienced an increase in arousal-like symptoms ('high energy'), shorter reaction times, a slight benefit to sustained attention, and a self-reported feeling of happiness before bedtime when taken 60–90 minutes before sleep.
Why it matters
Provides preliminary clinical trial evidence that low-dose dietary tryptophan from protein hydrolysate can modulate cognitive and emotional processing in healthy middle-aged individuals without pharmaceutical intervention.
Limits
The abstract reports directional findings only, without providing effect sizes, variance, or p-values. The sample size was modest (59 participants) and limited exclusively to healthy middle-aged women, precluding direct generalization to men, other age groups, or clinical populations with mood disorders. Treatment duration was brief (19 days).
Cited by
- supports Dietary tryptophan provided by protein serves as a precursor molecule for the synthesis of the neurotransmitter serotonin.