Objective: Most previous studies investigating amino acid levels in anorexia nervosa (AN) have focused on acutely underweight patients. The present study assessed the availability of aromatic amino acids in the plasma of weight-recovered outpatients with AN (recAN) in comparison to acutely underweight AN patients (acAN) and healthy control woman (HCW).
Method: Plasma tryptophan (TRP), tyrosine (TYR), and phenylalanine (PHEN) as well as leptin concentration were determined in 32 recAN, 32 acAN, and 32 HCW.
Results: Both recAN and acAN patients showed significantly lower levels of TRP and PHEN when compared to HCW. TYR was reduced in acAN patients only.
Discussion: Normal weight and normal leptin levels but lower availability of TRP and PHEN in recAN patients might indicate that outside a tightly controlled setting these patients still engage in abnormal eating patterns. Reduced peripheral availability of these precursor amino acids could impact on 5-HT and catecholamine functioning in the brain.