Canadian Journal of Physiology & Pharmacology
Volume 85(9), September 2007, pp928-32
Protein Source Tryptophan as an Efficacious Treatment for Social Anxiety Disorder: A Pilot Study
Craig Hudson MD FRCP(C)1,2 Susan Hudson MSW2, Joan MacKenzie RN3
1Whitby Mental Health Centre, 700 Gordon St., Whitby, OntarioL1N 5S9
2 Biosential Inc. 1543 Bayview Ave., Suite 346TorontoOntarioM4G 3B5
3 Stratford General Hospital, Department of Psychiatry, 46 General Hospital Dr., Stratford, Ontario N5A 2Y6
Abstract
BACKGROUND: Until recently intact protein rich in tryptophan was not seen as an alternative to pharmaceutical grade tryptophan since protein also contains large neutral amino acids (LNAAs) that compete for transport sites across the blood-brain-barrier. Recent evidence indicates that deoiled gourd seed (an extremely rich source of tryptophan - 22mg tryptophan/1g protein) when combined with glucose, a carbohydrate that reduces serum levels of competing LNAAs, has a clinical effect similar to pharmaceutical grade tryptophan. DESIGN: Objective and subjective measures of anxiety in those suffering from Social Phobia were employed to measure changes in anxiety in response to a stimulus as part of a double blind placebo controlled, cross-over study with a wash-out period of one week between study sessions. Subjects were randomly assigned to start with either: (1) protein source tryptophan (deoiled gourd seed) in combination with carbohydrate; or (2) carbohydrate alone. One week after the initial session subjects returned for a follow-up session and received the opposite treatment of that received at the first session. SUBJECTS: All 7 subjects who began the study completed the two week protocol. RESULTS: Protein source tryptophan with carbohydrate but not carbohydrate alone resulted in significant improvement on an objective measure of anxiety. CONCLUSION: Protein source tryptophan combined with a high glycemic carbohydrate is a potential anxiolytic to those suffering from Social Phobia also known as Social Anxiety Disorder.