Measurement of nutritional status in simulated microgravity by bioelectrical impedance spectroscopy

• Published in: Journal of applied physiology (1985) Vol. 95; no. 1; pp. 225 - 232
• Main Authors: Bartok, Cynthia, Atkinson, Richard L, Schoeller, Dale A
• Format: Journal Article
• Language: English
• Published: Legacy CDMS Am Physiological Soc 01.07.2003; American Physiological Society
• Subjects: Adult; Aerospace Medicine; Algorithms; Applied physiology; Bed Rest - adverse effects; Biological and medical sciences; Body Water - physiology; Body Weight - physiology; Deuterium; Electric Impedance; Extracellular Fluid - physiology; Female; Gravity; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; Impedance; Male; Medical sciences; Middle Aged; Nutrition; Nutritional Status; Reproducibility of Results; Space biology; Spectroscopy; Spectrum analysis; Transports. Aerospace. Diving. Altitude; Water; Weightlessness Simulation; Human; Body Weight/physiology; Support, U.s. Gov't, Non-P.h.s; Support, U.s. Gov't, P.h.s; Middle Aged; Non-Nasa Center; Male; Bed Rest/adverse Effects; Electric Impedance; Reproducibility Of Results; Algorithms; Nasa Program Biomedical Research And Countermeasures; Nasa Discipline Regulatory Physiology; Extracellular Fluid/physiology; Adult; Female; Nutritional Status; Weightlessness Simulation; Body Water/physiology; Water; head-down tilt; Environmental factor; Weightlessness; Extracellular; Body composition; Spectrometry; Simulation; total body water; Intracellular; Measurement method; intracellular water; Microgravity; extracellular water; Nutritional status; Electrical impedance; NASA Program Biomedical Research and Countermeasures; NASA Discipline Regulatory Physiology; Non-NASA Center
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00721.2002

Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin 53706 Submitted 5 August 2002 ; accepted in final form 22 January 2003 The potential of bioelectrical impedance spectroscopy (BIS) for assessing nutritional status in spaceflight was tested in two head-down-tilt bed-rest studies. BIS-predicted extracellular water (ECW), intracellular water (ICW), and total body water (TBW) measured using knee-elbow electrode placement were compared with deuterium and bromide dilution (DIL) volumes in healthy, 19- to 45-yr-old subjects. BIS was accurate during 44 h of head-down tilt with mean differences (BIS - DIL) of 0–0.1 kg for ECW, 0.3–0.5 for ICW, and 0.4–0.6 kg for TBW ( n = 28). At 44 h, BIS followed the within-individual change in body water compartments with a relative prediction error (standard error of the estimate/baseline volume) of 2.0–3.6% of water space. In the second study, BIS did not detect an acute decrease (-1.41 ± 0.91 kg) in ICW secondary to 48 h of a protein-free, 800 kcal/day diet ( n = 18). BIS's insensitivity to ICW losses may be because they were predominantly (65%) localized to the trunk and/or because there was a general failure of BIS to measure ICW independently of ECW and TBW. BIS may have potential for measuring nutritional status during spaceflight, but its limitations in precision and insensitivity to acute ICW changes warrant further validation studies. total body water; extracellular water; intracellular water; head-down tilt; body composition Address for reprint requests and other correspondence: D. A. Schoeller, Dept. of Nutritional Sciences, Univ. of Wisconsin, Madison, WI 53706. (E-mail: dschoell{at}nutrisci.wisc.edu ).