title: Use of the deuterated-retinol-dilution technique to assess total-body vitamin A stores of adult volunteers consuming different amounts of vitamin A.
abstract: BACKGROUND
  The deuterated-retinol-dilution (DRD) technique provides a quantitative estimate of total body stores of vitamin A. However, it is not known whether the technique can detect changes in vitamin A pool size in response to different intakes of vitamin A.
  
  
  OBJECTIVE
  Our objective was to determine the responsiveness of the DRD technique to 3 different daily supplemental vitamin A intakes during a period of 2.5-4 mo.
  
  
  METHODS
  Two oral doses of [(2)H(4)]retinyl acetate [52.4 micromol retinol equivalent (RE)] were administered on study days 1 and 91 to 26 men (18-32 y of age) who were consuming controlled, low-vitamin A diets, and receiving daily either 0, 5.2, or 10.5 micromol RE of unlabeled supplemental retinyl palmitate during a 75- or 129-d period. Plasma isotopic ratios of [(2)H(4)]retinol to retinol on day 115 were used to estimate final vitamin A body stores per Furr et al (Am J Clin Nutr 1989;49:713-6).
  
  
  RESULTS
  Final ( +/- SD) estimated vitamin A pool sizes were 0.048 +/- 0.031, 0.252 +/- 0.045, and 0.489 +/- 0.066 mmol in the treatment groups receiving 0, 5.2, and 10.5 micromol RE/d, respectively (P < 0.001). Estimated mean changes in vitamin A pool sizes were similar to those expected for the vitamin A-supplemented groups [estimated:expected (95% CI of change in pool size): 1.08 (0.8, 1.2) and 1.17 (1.0, 1.3)].
  
  
  CONCLUSIONS
  The DRD technique can detect changes in total body stores of vitamin A in response to different daily vitamin A supplements. However, abrupt changes in dietary vitamin A intake can affect estimates of total-body vitamin A stores.
authors.affiliation: Program in International Nutrition, Department of Nutrition, University of California, Davis, USA. mjhaskell@ucdavis.edu
authors.forename: M J
authors.initials: MJ
authors.lastname: Haskell
authors.forename: R N
authors.initials: RN
authors.lastname: Mazumder
authors.forename: J M
authors.initials: JM
authors.lastname: Peerson
authors.forename: A D
authors.initials: AD
authors.lastname: Jones
authors.forename: M A
authors.initials: MA
authors.lastname: Wahed
authors.forename: D
authors.initials: D
authors.lastname: Mahalanabis
authors.forename: K H
authors.initials: KH
authors.lastname: Brown
mesh_terms: D000293:Adolescent; D000328:Adult; D002851:Chromatography, High Pressure Liquid; D003903:Deuterium; D006801:Humans; D007201:Indicator Dilution Techniques; D008297:Male; D014801:Vitamin A / Q000008:administration & dosage* / Q000097:blood* / Q000378:metabolism
chemical_list: D014801:Vitamin A; D003903:Deuterium