title: Urinary 3-methylhistidine excretion: association with total body skeletal muscle mass by computerized axial tomography.
abstract: BACKGROUND
  The urinary excretion of endogenous 3-methylhistidine (3-MH) has been proposed as a predictor of skeletal muscle mass (SM). In this study, we report the relationship between 24-hour urinary 3-MH excretion and SM.
  
  
  METHODS
  Total body SM was measured by multiscan computerized axial tomography (CT) in a sample of 10 healthy adult men who followed a meat-free diet for 7 days. 3-MH was measured during the last 3 days of the meat-free diet protocol on consecutive 24-hour urine collections.
  
  
  RESULTS
  The 3-MH excretion was 216.3 +/- 44.7 mumol/d (mean +/- SD) and was found well associated with SM (in kilograms), SM = 0.0887 x 3-MH + 11.8; r = .88, p < .001. Compared with CT, the previous 3-MH-SM prediction equation suggested by Lukaski et al underestimated SM by an average of 8.9 kg in the 10 healthy men. This difference was caused by the Burkinshaw-Cohn neutron activation model, which underestimated SM and was used as the reference in the Lukaski method.
  
  
  CONCLUSIONS
  Twenty-four-hour urinary 3-MH excretion can be applied for estimating SM in healthy adult men on a meat-free diet.
authors.affiliation: Department of Medicine, St Luke's-Roosevelt Hospital, Columbia University College of Physicians and Surgeons, New York, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: P
authors.initials: P
authors.lastname: Deurenberg
authors.forename: D E
authors.initials: DE
authors.lastname: Matthews
authors.forename: S B
authors.initials: SB
authors.lastname: Heymsfield
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D000328:Adult; D015415:Biomarkers / Q000652:urine; D001823:Body Composition / Q000502:physiology*; D001824:Body Constitution; D003404:Creatinine / Q000652:urine; D014676:Diet, Vegetarian; D006801:Humans; D016014:Linear Models; D008297:Male; D008762:Methylhistidines / Q000652:urine*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed
chemical_list: D015415:Biomarkers; D008762:Methylhistidines; D003404:Creatinine; C028118:3-methylhistidine