|Partner Organization||Partner Country|
|University of Leiden||The Netherlands|
|Universidad de Extremadura||Spain|
|University of Bonn||Germany|
Recognition and understanding of intentions are key processes in social cognition. An important neuromodulator regulating social cognition is serotonin, the precursor of which is the essential amino acid tryptophan (TRP). Altered serotonin availability and metabolization is hypothesized for several mental problems, physical illnesses and further also for elderly individuals. Reduced TRP availability leads to weaker impulse control ability and higher aggression, while TRP supplementation promotes confidence.
We investigated the influence of TRP on social cognition with two social-cognitive tasks. In the moral task, participants rated the reprehensibility or permissibility of protagonists’ behaviors in short stories. In the other task, participants determined emotions from pictures of persons eye regions. Participants were given 5-hydroxytryptophan (5-HTP) or TRP and filled in food diaries or recalls. Further, participants filled in questionnaires e.g. on mood and empathy. 5-hydroxyindoleacetic acid (5-HIAA) was measured from urine samples and blood samples were taken for genetic analyses.
With 5-HTP or a TRP rich diet, immoral behavior without negative consequences for others was rated as more reprehensible, and during story reading activation in insula and supramarginal gyrus was increased after a 4-week TRP intake. An important covariate was the 5-HIAA as an indicator of serotonin status. The supramarginal gyrus is associated with empathy, pain and related information integration. Consistently, participants showed a stricter evaluation of bad behavior possibly due to better integration of information. No significant effects of TRP on emotion recognition were identified when including all age groups. Emotion recognition ability decreased with age, but not for positive emotions when consuming TRP, possibly indicating a compensatory effect. Likewise, TRP seemed to improve recognition of positive emotions in S´S´ allele carriers of the serotonin transporter polymorphism, additionally, better mood was found. The monoamine oxidase-A high activity allele (relevant for serotonin catabolism), together with the degree of methylation at a promoter CpG site on the tryptophan hydroxylase-2 gene (relevant for serotonin synthesis) explained significant proportions of variance in emotion recognition performance. Some other nutrients in the diet seemed to affect social cognition, e.g. cholesterol was negatively associated with perspective-taking.
In healthy individuals who have a lower TRP availability or an altered serotonin metabolism (e.g. older age, higher BMI, risk allele carriers, degree of methylation, natural nutrition), TRP supplementation could have a positive influence on social cognition. Besides the above mentioned factors, the 5-HIAA level might be an additional indicator for individualized diet recommendations. Our results regarding TRP may help to ameliorate interventions in healthy people at risk and initiate future research in this field.
Tryptophan compensated for age related social cognitive problems with recognizing positive emotions
A tryptophan-rich diet protected against depression and increased social cognition but the tryptophan effect on social cognition was not mediated via depression; some further nutrients in the diet seemed to affect mood and social cognition as well
5-hydroxytryptophan and a diet rich in tryptophan increased the condemnation of immoral behavior, possibly via a better integration of relevant information as tryptophan also increased brain activity in the insula and the supramarginal gyrus
The monoamine oxidase-A high activity allele (relevant for serotonin catabolism) together with the degree of methylation at a promoter CpG site on the tryptophan hydroxylase-2 gene (relevant for serotonin synthesis) explained significant proportions of variance in emotion recognition performance even after controlling for age and sex effects
Tryptophan improved the recognition of positive emotions in S´S´ allele carriers of the serotonin transporter polymorphism; additionally, better mood and further improvements in social cognition were found for this risk group when taking tryptophan especially in an elderly population
|Authors||Title||Year, Issue, PP||Partners Number||Doi|
|Target group||Authors||Means of communication||Hyperlink|
|researchers||Deris N, Melchers M, Felten A, Plieger T, Zamoscik V, Kirsch P, Colzato LS, & Reuter M, „Genetische Aspekte moralischen Urteilens: Die Bedeutung des CHRNA4 Gens“, Psychologie und Gehirn, Trier, 2017||talk|
|researchers and laypeople||Bravo R, Ugartemendia L, Castaño MY, Zamoscik V, Reuter M, Rodríguez AB, Kirsch P, “Dietetic tryptophan-enriched bars improve mood in young participants. Preliminary results suggest an improvement in social cognition in elderly participants depending on SLC6A4 genotype.”, Fifth International JPI HDHL Conference, Brussels, Belgium, 2019||poster|
|researchers and laypeople||Zamoscik V, Lischewski J, Schmidt SNL, Deris N, Bravo R, Ugartemendia L, Rodríguez Moratinos AB, Reuter M, Kirsch P, “Chocolate makes you happy and decide more ethically just? Influence of tryptophan on moral decision making”, Fifth International JPI HDHL Conference, Brussels, Belgium, 2019||poster|
|researchers (and laypeople)||Vera Zamoscik, Jana Lischewski, Yannick Schreiner, Stephanie NL Schmidt, Rafael Bravo Santos, Ana Rodríguez Moratinos, Martin Reuter, Peter Kirsch. "Influence of tryptophan on social cognition". CIMH retreat, Mannheim, 2019||poster|
|laypeople||Zamoscik V, „Von Biologie und Emotionen – Wie Sinne, Atmung und Ernährung unser Wohlbefinden beeinflussen.“ Convention ‚Unter Druck‘ Funktionelle und physiologische Aspekte des Atems im Tauchsport (Apnoe- und Gerätetauchen). Mošćenička Draga, Croatia, 2016||invited talk|
|Patent licence||Partners involved||Year||International eu or national patent||Comment|
|PhD thesis Ugartemendia L.: Tryptophan-based nutritional intervention effectiveness on age-related depression and social cognition in humans, based on SLC6A4 and BDNF genes. University of Extremadura.||all||expected 2020|
|Master thesis Lischewski J.: Effects of diet on mood and sleep quality: Ecological momentary assessment of naturally and experimentally varied tryptophan. University of Mannheim.||WP2||2018|
|Master thesis Ugartemendia L.: Influence of macronutrients and tryptophan ingest on mood and social cognition in university undergraduates. University of Extremadura.||mainly WP4||2018|
|Bachelor thesis Ugartemendia L.: The influence of 5-HTTLPR genotype on tryptophan metabolism in university students. University of Extremadura.||mainly WP4, WP5||2017|