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.

Effects of Diet on Sleep: A Narrative Review

“…Tryptophan-containing foods improved sleep indices compared with controls [15,27]. For example, compared with controls, an increase in total sleep time, sleep efficiency, and immobile time was noted after a week of tryptophan-rich (60 mg) cereal consumption in older adults [15].…”

“…Five studies were classified under this category based on the investigation of the effects of either tryptophan consumption [15,27] or acute tryptophan depletion [17,28,29] on sleep in otherwise healthy adults. All of the studies examining tryptophan depletion used PSG to measure sleep, while the studies investigating tryptophan consumption utilized actigraphy [15] and sleep diaries [27]. Table 1 summarizes the characteristics and outcomes of these studies.…”

Tryptophan supplementation and serotonin function: genetic variations in behavioural effects

“…Brain 5-HT synthesis rates are reportedly 50 % lower in women than men (105) , and ATD causes greater lowering of mood in women than men (106) . In some studies, women also appear to be more sensitive to, or to benefit more from, TRP supplementation; indeed, some researchers chose to study women only for these reasons (97,98) . Furthermore, sex interacts with serotonergic gene polymorphisms in several systems, including 5-HTTLPR, TPH1, TPH2 and MAO-A (67,107) , and these interactions can be further moderated by stress (108)(109)(110)(111) .…”

Ginger-Degraded Collagen Hydrolysate Exhibits Antidepressant Activity in Mice

“…Mori et al reported that soybean b-conglycinin hydrolysate with thermolysin had antidepressant activity via the vagus nerve in mice (18). Several groups reported that egg protein hydrolysate promoted mood and emotional function in humans (19)(20)(21). These results suggest that regulation of incentive may be impacted by food-derived peptides.…”