Validation of the doubly labeled water method using off-axis integrated cavity output spectroscopy and isotope ratio mass spectrometry.

ABSTRACT: When the doubly labeled water (DLW) method is used to measure total daily energy expenditure (TDEE), isotope measurements are typically performed using isotope ratio mass spectrometry (IRMS). New technologies, such as off-axis integrated cavity output spectroscopy (OA-ICOS) provide comparable isotopic measurements of standard waters and human urine samples, but the accuracy of carbon dioxide production (V̇co₂) determined with OA-ICOS has not been demonstrated. We compared simultaneous measurement V̇co₂ obtained using whole-room indirect calorimetry (IC) with DLW-based measurements from IRMS and OA-ICOS. Seventeen subjects (10 female; 22 to 63 yr) were studied for 7 consecutive days in the IC. Subjects consumed a dose of 0.25 g H₂¹⁸O (98% APE) and

SUBMITTER: Melanson EL 

PROVIDER: S-EPMC5866416 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature