title: Essential amino acids in the gluten-free diet and serum in relation to depression in patients with celiac disease.
abstract: BACKGROUND
  Celiac disease (CD) is associated with an increased risk of major depressive disorder, possibly due to deficiencies in micronutrients in the gluten-free diet. We aimed to investigate whether essential amino acids (i.e., the precursors of serotonin, dopamine and other neurotransmitters) are depleted in the diet and serum of CD patients with major depressive disorder.
  
  
  METHODS
  In a cross-sectional study we assessed dietary intake of amino acids and serum levels of amino acids, in 77 CD patients on a gluten-free diet and in 33 healthy controls. Major depressive disorder was assessed with structured interviews (using the Mini International Neuropsychiatric Interview Plus). Dietary intake was assessed using a 203-item food frequency questionnaire.
  
  
  RESULTS
  Participants had a mean age of 55 years and 74% were women. The intake of vegetable protein was significantly lower in CD patients than in healthy controls (mean difference of 7.8 g/d; 95% CI: 4.7-10.8), as were serum concentrations of tyrosine, phenylalanine and tryptophan (all p < 0.005). However, within the CD patient group, the presence of major depressive disorder (n = 42) was not associated with intake or serum levels of essential amino acids.
  
  
  CONCLUSIONS
  Patients with CD on a long-term gluten-free diet, with good adherence, consume significantly less vegetable protein than controls, and their serum levels of several essential amino acids were also lower. Despite its potential adverse effect, intake and serum levels of essential amino acids were not related to major depression.
authors.affiliation: Institute of Psychology, Leiden University, Leiden, The Netherlands.
authors.forename: Nathalie J M
authors.initials: NJ
authors.lastname: van Hees
authors.affiliation: Department of Psychiatry, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Erik J
authors.initials: EJ
authors.lastname: Giltay
authors.affiliation: Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands.
authors.forename: Susanne M A J
authors.initials: SM
authors.lastname: Tielemans
authors.affiliation: Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands.
authors.forename: Johanna M
authors.initials: JM
authors.lastname: Geleijnse
authors.affiliation: Leyden Academy on Vitality and Ageing, Leiden, The Netherlands.
authors.forename: Thomas
authors.initials: T
authors.lastname: Puvill
authors.affiliation: Institute of Psychology, Leiden University, Leiden, The Netherlands.
authors.forename: Nadine
authors.initials: N
authors.lastname: Janssen
authors.affiliation: Institute of Psychology, Leiden University, Leiden, The Netherlands; Department of Psychiatry, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Willem
authors.initials: W
authors.lastname: van der Does
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000601:Amino Acids, Essential / Q000097:blood*; D015992:Body Mass Index; D002446:Celiac Disease / Q000097:blood* / Q000150:complications* / Q000473:pathology*; D002851:Chromatography, High Pressure Liquid; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000150:complications* / Q000175:diagnosis*; D055050:Diet, Gluten-Free; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D010349:Patient Compliance; D011795:Surveys and Questionnaires
chemical_list: D000601:Amino Acids, Essential