Dietary intake of tryptophan tied emotion-related impulsivity in humans
Abstract
Abstract. Emotion-related impulsivity, defined as the tendency to say or do things that one later regret during periods of heightened emotion, has been tied to a broad range of psychopathologies. Previous work has suggested that emotion-related impulsivity is tied to an impaired function of the serotonergic system. Central serotonin synthesis relies on the intake of the essential amino acid, tryptophan and its ability to pass through the blood brain barrier. Objective: The aim of this study was to determine the association between emotion-related impulsivity and tryptophan intake. Methods: Undergraduate participants (N = 25, 16 women, 9 men) completed a self-rated measure of impulsivity (Three Factor Impulsivity Index, TFI) and daily logs of their food intake and exercise. These data were coded using the software NutriNote to evaluate intakes of tryptophan, large neutral amino acids, vitamins B6/B12, and exercise. Results: Correlational analyses indicated that higher tryptophan intake was associated with significantly lower scores on two out of three subscales of the TFI, Pervasive Influence of Feelings scores r = –.502, p < .010, and (lack-of) Follow-Through scores, r = –.407, p < .050. Conclusion: Findings provide further evidence that emotion-related impulsivity is correlated to serotonergic indices, even when considering only food habits. It also suggests the need for more research on whether tryptophan supplements might be beneficial for impulsive persons suffering from a psychological disorder.
References
1 (2008) Serotonergic function, two-mode models of self-regulation, and vulnerability to depression: What depression has in common with impulsive aggression. Psychol. Bull. 134 (6), 912–943.
2 (1985) Age norms for impulsiveness, venturesomeness and empathy in adults. Pers. Individ. Dif. 6 (5), 613–619.
3 (2015) Parsing the heterogeneity of impulsivity: A meta-analytic review of the behavioral implications of the UPPS for psychopathology. Psychol. Assess. 27 (4), 1129–1146.
4 (2007) Impulsivity as a predictor of newly diagnosed depression. Scand. J. Psychol. 48 (2), 173–179.
5 (1995) Factor structure of the Barratt impulsiveness scale. J. Clin. Psychol. 51 (6), 768–74.
6 (2001) The Five Factor Model and impulsivity: Using a structural model of personality to understand impulsivity. Pers. Individ. Dif. 30 (4), 669–689.
7 (2011) Serotonin transporter polymorphism interacts with childhood adversity to predict aspects of impulsivity. Psychol. Sci. 22 (5), 589–595.
8 (2013) ‘Impulsivity’: Relations between self-report and behavior. J. Pers. Soc. Psychol. 104 (3), 559–575.
9 (2008) Neurobehavioral mechanisms of impulsivity: Fronto-striatal systems and functional neurochemistry. Pharmacol. Biochem. Behav. 90 (2), 250–260.
10 (2015) Dissociable roles of dopamine and serotonin transporter function in a rat model of negative urgency. Behav. Brain Res. 291, 201–208.
11 (2000) Use of neurotransmitter precursors for treatment of depression. Altern. Med. Rev. 5 (1), 64–71.
12 (2016) The serotonergic system in the neurobiology of depression: Relevance for novel antidepressants. J. Psychopharmacol. 30 (1), 13–22.
13 (2001) Physiology and pathophysiology of the serotonergic system and its implications on mental and physical performance. Part II. Int. J. Sports Med. 22 (7), 482–497.
14 (2013) Tryptophan-enriched cereal intake improves nocturnal sleep, melatonin, serotonin, and total antioxidant capacity levels and mood in elderly humans. Age (Omaha). 35 (4), 1277–1285.
15 (2015) The effects of dietary tryptophan on affective disorders. Arch. Psychiatr. Nurs. 29 (2), 102–107.
16 (1981) Effect of tryptophan administration on tryptophan, 5-hydroxyindoleacetic acid and indoleacetic acid in human lumbar and cisternal cerebrospinal fluid. J. Neurol. Neurosurg. Psychiatry. 44 (4), 323–8.
17 (2006) Social behaviour and mood in everyday life: The effects of tryptophan in quarrelsome individuals. J. Psychiatry Neurosci. 31 (4), 253–262.
18 (2007) Attention switching after dietary brain 5-HT challenge in high impulsive subjects. J. Psychopharmacol. 21 (7), 700–708.
19 (2001) The effect of tryptophan on social interaction in everyday life-A placebo-controlled study. Neuropsychopharmacology. 25 (01), 277–289.
20 (2014) Serotonin (5HT) expression in rat pups treated with high-tryptophan diet during fetal and early postnatal development. Acta Histochem. 116 (2), 335–343.
21 (2015) Changes in serotonin (5-HT) and brain-derived neurotrophic factor (BDFN) expression in frontal cortex and hippocampus of aged rat treated with high tryptophan diet. Brain Res. Bull. 119, 12–18.
22 (2010) Effects of acute tryptophan depletion on three different types of behavioral impulsivity. Int. J. tryptophan Res. IJTR. 3, 99–111.
23 (2013) The effect of raising and lowering tryptophan levels on human mood and social behaviour. Philos. Trans. R. Soc. B Biol. Sci. 368 (1615), 20110375.
24 (2013) Effect of diet on serotonergic neurotransmission in depression. Neurochem. Int. 62 (3), 324–329.
25 (2013) Large neutral amino acids: Dietary effects on brain neurochemistry and function. Amino Acids. 45 (3), 419–430.
26 (2007) Amino acids and the brain: Do they play a role in ‘central fatigue’? Int. J. Sport Nutr. Exerc. Metab. 17 (Suppl), S37–46.
27 (2008) Catecholamines and the effects of exercise, training and gender. Sports Med. 38 (5), 401–23.
28 (2011) Effect of hydrolysed egg protein on brain tryptophan availability. Br. J. Nutr. 105 (04), 611–617.
29 (2011) Monoamine depletion by reuptake inhibitors. Drug. Healthc. Patient Saf. 3, 69–77.
30 (1985) Tryptophan to competing amino acids ratio in depressive disorder: Relation to efficacy of antidepressive treatments. Acta Psychiatr. Scand. Suppl. 325, 3–31.
31 (2007) Tyrosine, phenylalanine, and catecholamine synthesis and function in the brain. J. Nutr. 137 (6 Suppl 1), 1539S–1547S. discussion 1548S.
32 (2002) Behavioural effects of acute phenylalanine and tyrosine depletion in healthy male volunteers. J. Psychopharmacol. 16 (1), 51–55.
33 (2013) Catecholamine receptors differentially mediate impulsive choice in the medial prefrontal and orbitofrontal cortex. J. Psychopharmacol. 27 (2), 203–212.
34 (2004) Patients with carcinoid syndrome exhibit symptoms of aggressive impulse dysregulation. Psychosom. Med. 66 (3), 422–5.
35 (2008) Effect of different tryptophan sources on amino acids availability to the brain and mood in healthy volunteers. Psychopharmacology (Berl). 201 (1), 107–114.
36 (2016) Switching and stopping antidepressants. Aust. Prescr. 39 (3), 76–83.
37 (2013) Impulsivity and risk for mania: Towards greater specificity. Psychol. Psychother. Theory, Res. Pract. 86 (4), 401–412.
38 (2016) Positive urgency is related to difficulty inhibiting prepotent responses. Emotion.
39 (2017) Impulsivity and suicidality in adolescent inpatients. J. Abnorm. Child Psychol. 45 (1), 91–103.
40 (2017) Comparing the standards of one metabolic equivalent of task in accurately estimating physical activity energy expenditure based on acceleration. J. Sports Sci. 35 (13), 1279–1286.
41 . (2007) Protein and amino acid requirements in human nutrition. World Health Organ. Tech. Rep. Ser. (935), 1–265. back cover.
42 (2012) 5-HTP efficacy and contraindications. Neuropsychiatr. Dis. Treat. 8, 323–8.
43 (2001) Evaluation of dietary assessment instruments against doubly labeled water, a biomarker of habitual energy intake. Am. J. Physiol. Metab. 281 (5), E891–E899.
44 (2008) Underreporting of energy intake in Brazilian women varies according to dietary assessment: A cross-sectional study using doubly labeled water. J. Am. Diet. Assoc. 108 (12), 2031–2040.
45 (2016) Plasma concentrations and intakes of amino acids in male meat-eaters, fish-eaters, vegetarians and vegans: A cross-sectional analysis in the EPIC-Oxford cohort. Eur. J. Clin. Nutr. 70 (3), 306–312.
46 (2001) The effect of tryptophan on social interaction in everyday life: A placebo-controlled study. Neuropsychopharmacol. Off. Publ. Am. Coll. Neuropsychopharmacol. 25 (2), 277–289.
47 (1997) L-tryptophan augmentation of light therapy in patients with seasonal affective disorder. Can. J. Psychiatry. 42 (3), 303–306.
48 (1990) Tryptophan treatment of aggressive psychiatric inpatients. Biol. Psychiatry. 28 (8), 728–732.
49 (2016) Stress, the autonomic nervous system, and the immune-kynurenine pathway in the etiology of depression. Curr. Neuropharmacol. 14 (7), 665–673.