Energy expenditure by doubly labeled water: validation in humans and proposed calculation.

Details

Serval ID
serval:BIB_13FB8EC10A65
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Energy expenditure by doubly labeled water: validation in humans and proposed calculation.
Journal
American Journal of Physiology. Regulatory Integrative and Comparative Physiology
Author(s)
Schoeller D.A., Ravussin E., Schutz Y., Acheson K.J., Baertschi P., Jéquier E.
ISSN
0363-6119 (Print)
ISSN-L
0002-9513
Publication state
Published
Issued date
1986
Volume
250
Number
5 Pt 2
Pages
R823-R830
Language
english
Abstract
To further validate the doubly labeled water method for measurement of CO2 production and energy expenditure in humans, we compared it with near-continuous respiratory gas exchange in nine healthy young adult males. Subjects were housed in a respiratory chamber for 4 days. Each received 2H2(18)O at either a low (n = 6) or a moderate (n = 3) isotope dose. Low and moderate doses produced initial 2H enrichments of 5 and 10 X 10(-3) atom percent excess, respectively, and initial 18O enrichments of 2 and 2.5 X 10(-2) atom percent excess, respectively. Total body water was calculated from isotope dilution in saliva collected at 4 and 5 h after the dose. CO2 production was calculated by the two-point method using the isotopic enrichments of urines collected just before each subject entered and left the chamber. Isotope enrichments relative to predose samples were measured by isotope ratio mass spectrometry. At low isotope dose, doubly labeled water overestimated average daily energy expenditure by 8 +/- 9% (SD) (range -7 to 22%). At moderate dose the difference was reduced to +4 +/- 5% (range 0-9%). The isotope elimination curves for 2H and 18O from serial urines collected from one of the subjects showed expected diurnal variations but were otherwise quite smooth. The overestimate may be due to approximations in the corrections for isotope fractionation and isotope dilution. An alternative approach to the corrections is presented that reduces the overestimate to 1%.
Keywords
Adult, Carbon Dioxide/biosynthesis, Deuterium/diagnostic use, Energy Metabolism, Humans, Male, Mathematics, Oxygen Isotopes, Pulmonary Gas Exchange, Water/diagnostic use
Pubmed
Web of science
Create date
21/01/2008 13:08
Last modification date
20/08/2019 12:42
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