title: Differential effect of the 5-HTT gene-linked polymorphic region on emotional eating during stress exposure following tryptophan challenge.
abstract: Stress and negative moods, which are thought to be partly mediated by reduced brain serotonin function, often increase emotional eating in dieting women (restrainers). Because the short (S) allele polymorphism in the serotonin transporter gene (5-HTTLPR) is associated with serotonin dysfunction, S allele compared to long (L) allele 5-HTTLPR genotypes may be more susceptible to stress-induced emotional eating. Consequently, serotonin challenge via tryptophan (TRP)-rich protein hydrolysate (TPH) may alleviate stress-induced emotional eating particularly in S/S allele carriers. We tested whether acute stress affects emotional eating in women with high or low dietary restraints depending on their 5-HTTLPR genotype and TPH intake. Nineteen female subjects who were homozygous for the short-allele 5-HTTLPR genotype (S'/S'=S/L(G), L(G)/L(G): restrainers vs. nonrestrainers) and 23 female subjects who were homozygous for the long-allele 5-HTTLPR genotype (L'/L'=L(A)/L(A): restrainers vs. nonrestrainers) were tested in a double-blind, placebo-controlled crossover study of stress-induced emotional eating following intake of TPH or a placebo. TPH intake significantly increased the plasma TRP/large neutral amino acid ratio (P<.0001) in the L'/L' group (70%) compared to the S'/S' group (30%). TPH reduced food intake in both groups, but in the L'/L' group, it also reduced stress-induced negative mood (P=.037) and the desire for sweet, high-fat foods (P=.011) regardless of dietary restraint.
  
  
  CONCLUSIONS
  Since TPH caused a greater increase in the plasma TRP/large neutral amino acid ratio in the L'/L' group compared to S'/S' group, the exclusive beneficial effects of L'/L' genotype may be due to enhanced brain 5-HT function.
authors.affiliation: Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands. r.markus@psychology.unimaas.nl
authors.forename: C Rob
authors.initials: CR
authors.lastname: Markus
authors.forename: Ellen
authors.initials: E
authors.lastname: Verschoor
authors.forename: Tom
authors.initials: T
authors.lastname: Smeets
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D001921:Brain / Q000378:metabolism; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004435:Eating / Q000187:drug effects; D004644:Emotions / Q000187:drug effects* / Q000502:physiology; D005260:Female; D005838:Genotype; D006801:Humans; D007407:Interviews as Topic; D011110:Polymorphism, Genetic; D012701:Serotonin / Q000378:metabolism; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D013315:Stress, Psychological / Q000139:chemically induced / Q000235:genetics* / Q000378:metabolism* / Q000523:psychology; D011795:Surveys and Questionnaires; D014364:Tryptophan / Q000494:pharmacology*; D055815:Young Adult
chemical_list: C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D012701:Serotonin; D014364:Tryptophan