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

Journal Article · Thu May 01 00:00:00 EDT 1986 · Am. J. Physiol.; (United States)

OSTI ID:5425867

Schoeller, D A; Ravussin, E; Schutz, Y; Acheson, K J; Baertschi, P; Jequier, E

To further validate the doubly labeled water method for measurement of CO/sub 2/ 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 /sup 2/H/sub 2/(18)O at either a low (n = 6) or a moderate (n = 3) isotope dose. Low and moderate doses produced initial /sup 2/H 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. CO/sub 2/ 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 /sup 2/H 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%.

• Research Organization: Univ. of Chicago, IL
• OSTI ID: 5425867
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States)
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
RESPIRATION
DYNAMIC FUNCTION STUDIES
CARBON DIOXIDE
DAILY VARIATIONS
DEUTERIUM
DOUBLE LABELLING
ISOTOPE DILUTION
OXYGEN ISOTOPES
SALIVA
URINE
VALIDATION
WATER
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY FLUIDS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLING
LIGHT NUCLEI
MATERIALS
NUCLEI
ODD-ODD NUCLEI
OXIDES
OXYGEN COMPOUNDS
STABLE ISOTOPES
TESTING
TRACER TECHNIQUES
VARIATIONS
WASTES
551001* - Physiological Systems- Tracer Techniques