Monday Oct 21, 2013 (foodconsumer.org) -- A new study in Psychoneuroendocrinology suggests that taking an amino acid called tryptophan as a dietary supplement can help relieve symptoms of depression and anxiety in patients with a type of eating disorder called anorexia nervosa - one of common eating disorders. 

Clair Gauthier from Université Paris Descartes, Paris, France and colleagues conducted the study and found an association between levels of tryptophan and severity of depression or depressive symptoms.

"Anorexia nervosa is an eating disorder characterized by immoderate food restriction and irrational fear of gaining weight, as well as a distorted body self-perception. It typically involves excessive weight loss and usually occurs more in females than in males," according to wikipedia.

The authors of the study say that anorexia nervosa has often times symptoms like depression, anxiety and obsession as well as physical changes caused by starvation.  They proposed that these symptoms are caused by reduced availability of tryptophan, which further results in a reduced serotonin activity.

The study was intended to examine how tryptophan supplementation may help people with anorexia nervosa.  For the study, 42 patients with anorexia nervosa were compared with 42 individuals without the health condition for a range of biomarkers before and after supplementation.

The researchers found that levels of serotonin markers were significantly lower in people with anorexia nervosa compared with the controls both at baseline (admission to hospitals for inpatient treatment) and at discharge.  Synthesis of serotonin needs tryptophan.  In other words, patients with anorexia nervosa may suffer serotonin deficiency.

Also an increase in the TRP/LNAA ratio was associated with a decrease in severity of depression or depressive symptoms, meaning that high concentrations of tryptophan alleviate depressive symptoms. 

Similarly serotonin levels were correlated with symptoms of both anxiety and depression at discharge.  Tryptophan is a precursor to serotonin.

Tryptophan is available as a dietary supplement on the Internet or local health stores.  A daily dose of up to 5 grams of tryptophan seems to be safe, according to another study recently published in Journal of Nutrition.  (DL)