American Journal of Physiology - Endocrinology and Metabolism
American Journal of Physiology - Endocrinology and Metabolism
5 years ago

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

Plasqui, Wouters, Kohrt, Melanson, Speakman, Swibas, Creasy, Berman, Catenacci
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 (VCO2) determined with OA-ICOS has not been demonstrated. We compared simultaneous measurement of VCO2 obtained using whole-room indirect calorimetry (IC) with DLW-based measurements from IRMS and OA-ICOS. 17 subjects (10 female; 22 to 63 yrs.) were studied for 7 consecutive days in the IC. Subjects consumed a dose of 0.25 g H2(18)O (95% APE) and 0.14 g (2)H2O (99.8% APE) per kg of total body water, and urine samples were obtained on days 1 and 8 to measure average daily VCO2 using OA-ICOS and IRMS. VCO2 was calculated using both the plateau and intercept methods. There were no differences in VCO2 or TDEE measured by OA-ICOS or IRMS compared with IC when the plateau method was used. When the intercept method was used, VCO2 measured using OA-ICOS did not differ from IC, but VCO2 measured using IRMS was significantly lower than IC. Accuracy (~1-5%), precision (~8%), intraclass correlation coefficients (R=0.87-90), and root mean squared error (30-40 L/day) of VCO22 measured by OA-ICOS and IRMS were similar. Both OA-ICOS and IRMS produced measurements of VCO2 with comparable accuracy and precision when compared to IC.

Publisher URL: http://doi.org/10.1152/ajpendo.00241.2017

DOI: 10.1152/ajpendo.00241.2017

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.