Characterization of Differential Amino Acid Homeostasis amongst Population Subgroups: A Basis for Determining Specific Amino Acid Requirements

Abstract

Purpose: To measure the urinary excretion of amino acids in a large number of patients with chronic fatigue/pain disorders to determine whether distinct subgroups can be defined on the basis of the urine excretion patterns. Design: Laboratory-based survey, with comparison to prior control, chronic orofacial muscle pain and rheumatoid arthritis datasets. Materials and Methods: Urine samples and symptom data were collected from 1993 referral patients, with varying forms of chronic fatigue and pain conditions (including CFS and fibromyalgia), as part of their normal clinical evaluation over a period from June 1997 to October 1998. Each urine sample was analyzed for amino and organic acid content by gas chromatography-mass spectrometry (GC-MS). The urine profile data were analyzed by K-means clustering techniques. Results: It was found that six subgroups of patients could be delineated on the basis of the distributions of 13 amino acids measured in the urine. These groups were extremely well resolved by discr...