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Effects of acute treatment with a tryptophan-rich protein hydrolysate on plasma amino acids, mood and emotional functioning in older women.

Gibson EL, Vargas K, Hogan E, Holmes A, Rogers PJ, Wittwer J, Kloek J, Goralczyk R, Mohajeri MH - Psychopharmacology (Berl.) (2014)

Bottom Line: This treatment dose resulted in a significant shift in emotional processing towards positive words and reduced negative bias in assessing negative facial expressions.However, there was no evidence for any adverse effects.Consumption of a low dose of TRP-rich protein hydrolysate may have beneficial effects on emotional function that could promote feelings of wellbeing, possibly conferring resistance to deterioration in mood in healthy subjects or depressive episodes.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Whitelands College, University of Roehampton, Holybourne Avenue, London, SW15 4JD, UK, l.gibson@roehampton.ac.uk.

ABSTRACT

Rationale: Effective functioning of the neurotransmitter serotonin is important for optimal cognitive and emotional function. Dietary supplements able to increase availability to the brain of the precursor amino acid, tryptophan (TRP), and thereby enhance serotonin synthesis, can have measurable impact on these psychological processes.

Objectives: This study involves a randomised controlled trial of a TRP-rich egg-white protein hydrolysate (DSM Nutritional Products Ltd., Switzerland) on plasma amino acids, cognition, mood and emotional processing in older women.

Methods: Following a baseline test day without treatment, 60 healthy women aged 45-65 years received drinks containing either 2 or 4 g of TRP-rich protein hydrolysate product or 3.11 g casein hydrolysate as a control. One hour later, they undertook a 2-h battery of cognitive and emotional tests.

Results: The TRP-rich protein hydrolysate produced the expected dose-dependent increase in the ratio of plasma TRP to competing large neutral amino acids. TRP-rich protein hydrolysate (2 g only) prevented both the decline in wellbeing and increase in fatigue seen over the test session in the control group. This treatment dose resulted in a significant shift in emotional processing towards positive words and reduced negative bias in assessing negative facial expressions. Effects on cognition were small and not statistically reliable and are not reported here. However, there was no evidence for any adverse effects.

Conclusions: Consumption of a low dose of TRP-rich protein hydrolysate may have beneficial effects on emotional function that could promote feelings of wellbeing, possibly conferring resistance to deterioration in mood in healthy subjects or depressive episodes.

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Related in: MedlinePlus

Effect of LumiVida™ on errors of omission for positive target words (with negative or neutral distractor words; all trials). The lowest dose (2 g) of LumiVida™ (hashed column) significantly reduced the number of errors, *p < 0.02 vs. control (open column); 4 g LumiVida™ (solid column) did not differ from the control. Means are adjusted for baseline performance, age, NART errors and neuroticism. Data are natural log transformed to normalise positive skew
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Fig6: Effect of LumiVida™ on errors of omission for positive target words (with negative or neutral distractor words; all trials). The lowest dose (2 g) of LumiVida™ (hashed column) significantly reduced the number of errors, *p < 0.02 vs. control (open column); 4 g LumiVida™ (solid column) did not differ from the control. Means are adjusted for baseline performance, age, NART errors and neuroticism. Data are natural log transformed to normalise positive skew

Mentions: These errors indicate failing to press the key in response to a target word. It was predicted that LumiVida™ would reduce such errors when the target was positive and distractors were negative or neutral. Similarly to latency data, there was a significant effect of treatment for the positive target condition; moreover, neuroticism was a significant covariate for this variable, F(1, 52) = 6.10, p < 0.02, ηp2 = 0.11, and the resulting adjusted main effect of treatment was strongly significant, ANCOVA group effect, F(2, 52) = 6.49, p < 0.01, ηp2 = 0.20. Planned contrasts showed that this effect was due to a reduction in omissions after 2 g LumiVida™ vs. control, p < 0.02, but not after 4 g LumiVida™ vs. control, p > 0.1 (Fig. 6). This suggests that the presence of negative or neutral distractors produced less interference in accuracy of responding to positive targets after the low dose of LumiVida™. There were no significant effects of treatment on omission errors for negative target words (F < 1.62). There were also no effects of treatment on errors of commission (i.e. incorrect key pressing to a distractor word; F < 1).Fig. 6


Effects of acute treatment with a tryptophan-rich protein hydrolysate on plasma amino acids, mood and emotional functioning in older women.

Gibson EL, Vargas K, Hogan E, Holmes A, Rogers PJ, Wittwer J, Kloek J, Goralczyk R, Mohajeri MH - Psychopharmacology (Berl.) (2014)

Effect of LumiVida™ on errors of omission for positive target words (with negative or neutral distractor words; all trials). The lowest dose (2 g) of LumiVida™ (hashed column) significantly reduced the number of errors, *p < 0.02 vs. control (open column); 4 g LumiVida™ (solid column) did not differ from the control. Means are adjusted for baseline performance, age, NART errors and neuroticism. Data are natural log transformed to normalise positive skew
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4231284&req=5

Fig6: Effect of LumiVida™ on errors of omission for positive target words (with negative or neutral distractor words; all trials). The lowest dose (2 g) of LumiVida™ (hashed column) significantly reduced the number of errors, *p < 0.02 vs. control (open column); 4 g LumiVida™ (solid column) did not differ from the control. Means are adjusted for baseline performance, age, NART errors and neuroticism. Data are natural log transformed to normalise positive skew
Mentions: These errors indicate failing to press the key in response to a target word. It was predicted that LumiVida™ would reduce such errors when the target was positive and distractors were negative or neutral. Similarly to latency data, there was a significant effect of treatment for the positive target condition; moreover, neuroticism was a significant covariate for this variable, F(1, 52) = 6.10, p < 0.02, ηp2 = 0.11, and the resulting adjusted main effect of treatment was strongly significant, ANCOVA group effect, F(2, 52) = 6.49, p < 0.01, ηp2 = 0.20. Planned contrasts showed that this effect was due to a reduction in omissions after 2 g LumiVida™ vs. control, p < 0.02, but not after 4 g LumiVida™ vs. control, p > 0.1 (Fig. 6). This suggests that the presence of negative or neutral distractors produced less interference in accuracy of responding to positive targets after the low dose of LumiVida™. There were no significant effects of treatment on omission errors for negative target words (F < 1.62). There were also no effects of treatment on errors of commission (i.e. incorrect key pressing to a distractor word; F < 1).Fig. 6

Bottom Line: This treatment dose resulted in a significant shift in emotional processing towards positive words and reduced negative bias in assessing negative facial expressions.However, there was no evidence for any adverse effects.Consumption of a low dose of TRP-rich protein hydrolysate may have beneficial effects on emotional function that could promote feelings of wellbeing, possibly conferring resistance to deterioration in mood in healthy subjects or depressive episodes.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Whitelands College, University of Roehampton, Holybourne Avenue, London, SW15 4JD, UK, l.gibson@roehampton.ac.uk.

ABSTRACT

Rationale: Effective functioning of the neurotransmitter serotonin is important for optimal cognitive and emotional function. Dietary supplements able to increase availability to the brain of the precursor amino acid, tryptophan (TRP), and thereby enhance serotonin synthesis, can have measurable impact on these psychological processes.

Objectives: This study involves a randomised controlled trial of a TRP-rich egg-white protein hydrolysate (DSM Nutritional Products Ltd., Switzerland) on plasma amino acids, cognition, mood and emotional processing in older women.

Methods: Following a baseline test day without treatment, 60 healthy women aged 45-65 years received drinks containing either 2 or 4 g of TRP-rich protein hydrolysate product or 3.11 g casein hydrolysate as a control. One hour later, they undertook a 2-h battery of cognitive and emotional tests.

Results: The TRP-rich protein hydrolysate produced the expected dose-dependent increase in the ratio of plasma TRP to competing large neutral amino acids. TRP-rich protein hydrolysate (2 g only) prevented both the decline in wellbeing and increase in fatigue seen over the test session in the control group. This treatment dose resulted in a significant shift in emotional processing towards positive words and reduced negative bias in assessing negative facial expressions. Effects on cognition were small and not statistically reliable and are not reported here. However, there was no evidence for any adverse effects.

Conclusions: Consumption of a low dose of TRP-rich protein hydrolysate may have beneficial effects on emotional function that could promote feelings of wellbeing, possibly conferring resistance to deterioration in mood in healthy subjects or depressive episodes.

Show MeSH
Related in: MedlinePlus