This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Favaro, A. Articles by Santonastaso, P. Search for Related Content PubMed PubMed Citation Articles by Favaro, A. Articles by Santonastaso, P. Related Collections Exercise Neuroendocrine Eating Disorder

Tryptophan Levels, Excessive Exercise, and Nutritional Status in Anorexia Nervosa

From the Departments of Neurologic and Psychiatric Sciences (A.F., P.S.), Clinical Medicine (L.C.), and Pediatrics (A.B.), University of Padua, Padua, Italy.

Address reprint requests to: Prof. Paolo Santonastaso, Clinica Psichiatrica, Dip. Scienze Neurologiche e Psichiatriche, Via Giustiniani, 3 35128 Padova, Italy. Email: santopla{at}ux1.unipd.it

OBJECTIVE: It has been hypothesized that reduced dietary availability of tryptophan may be the cause of impaired serotonin activity in underweight anorexics. The study reported here evaluated the relationship between tryptophan availability in the blood and nutritional status in anorexia nervosa.

METHODS: The total amount of tryptophan and the ratio between tryptophan and other large neutral amino acids (TRP/LNAA) were assessed in a sample of 16 starving anorexic patients. Body weight and composition and energy intake were evaluated in all patients. All subjects also completed self-reported questionnaires such as the Hopkins Symptom Checklist and Eating Disorders Inventory (EDI).

RESULTS: The TRP/LNAA ratio seems to be higher in patients with a more severe catabolic status. It is, in fact, significantly inversely correlated with body mass index, body fat, muscle mass, daily energy intake, and daily tryptophan intake. The TRP/LNAA ratio also correlates with growth hormone and the EDI drive for thinness. Patients who exercise excessively had significantly higher TRP/LNAA ratios.

CONCLUSIONS: In starving anorexic patients, the TRP/LNAA ratio does not seem to be determined by the content of tryptophan in the diet, but it correlates with measures of catabolism. The relationship of the TRP/LNAA ratio to excessive exercise and starvation indicates the importance of further investigations exploring the role of tryptophan availability in maintaining anorexia nervosa.

Key Words: anorexia nervosa • tryptophan • serotonin • hyperactivity • starvation

Abbreviations: AN = anorexia nervosa; BMI = body mass index; DSM-IV= Diagnostic and Statistical Manual of Mental Disorders,fourth edition; EDI = Eating Disorders Inventory; GH = growthhormone; HSCL = Hopkins Symptom Checklist; LNAA = largeneutral amino acids; MAC = mid-upper arm circumference; MAMC= midarm muscle circumference; TRP = tryptophan; TSF =triceps skinfold; 5-HT = 5-hydroxytryptamine.

This article has been cited by other articles:

				B. J. Cook and H. A. Hausenblas The Role of Exercise Dependence for the Relationship between Exercise Behavior and Eating Pathology: Mediator or Moderator? J Health Psychol, May 1, 2008; 13(4): 495 - 502. [Abstract] [PDF]

				A. Favaro, L. Caregaro, L. Di Pascoli, F. Brambilla, and P. Santonastaso Total Serum Cholesterol and Suicidality in Anorexia Nervosa Psychosom Med, July 1, 2004; 66(4): 548 - 552. [Abstract] [Full Text] [PDF]