ABSTRACT
BACKGROUND: The doubly labelled water (DLW) method is the technique of choice for measurement of free-living total energy expenditure (TEE) in humans. A major constraint on the clinical applicability of the method has been the expense of the (18)O isotope. METHOD: We have used a reduced-dose (one-tenth of the currently recommended standard dose) of DLW for the measurement of TEE and body composition in nine healthy adult male volunteers. RESULTS: TEE measured by reduced-dose DLW was positively correlated with resting energy expenditure measured by metabolic cart (r=0.87, P<0.01). Isotope-derived fat mass and body mass index were strongly correlated (r=0.86, P<0.01). In four subjects in whom we performed a complementary evaluation using standard-dose isotope enrichment, the TEE measurements were satisfactorily comparable (mean+/-s.d.: reduced dose 2586+/-155 kcal/day vs standard dose 2843+/-321 kcal/day; mean difference 257+/-265 kcal/day). CONCLUSION: These data indicate that DLW measurements of human energy expenditure and body composition can be performed at a substantially reduced dose (and cost) of isotope enrichment than is currently employed.
