Doubly Labeled Water (DLW)
The DLW method allows investigators to measure the total daily energy expenditure of their participants in a free living environment over a period of 1-2 weeks.
About the DLW CORE
In 2019, the Energy Metabolism Laboratory established the DLW Isotope Core. The establishment of this Core was made possible through funding from the Dean of the University of Colorado School of Medicine (Strategic Infrastructure for Research Initiatives). In addition, we received support from the Colorado Clinical and Translational Sciences Institute (CCTSI), the Colorado Nutrition and Obesity Researcg Center (NORC), the Division of Endocrinology, Metabolism and Diabetes, the Department of Pediatrics at the Children's Hospital Colorado, the Anschutz Health and Wellness Center, the Section of Nutrition, and the Vice Chancellor of Research. The goal of the DLW Isotope Core is to provide accurate and precise measurements of deuterium and 18O in human urine, saliva, and plasma. Our lab currently houses two laser-based isotope analyzers which operate daily. We analyze each sample in duplicate with interleaved standards and internal controls, and employ several quality control checks. Currently, the DLW Isotope Core is analyzing samples for 7 NIH-funded studies.
If you are interested in collaborations or using the DLW method in your study, please contact Dr. Seth Creasy.
How does doubly labeled water (DLW) work?
Study participants are dosed with a precisely measured sample of heavy water (using stable, safe for consumption isotopes of deuterium and 18O). Urine, saliva, and/or plasma samples are collected before dosing and at 4 hours, 5 hours, and again 7 days after dosing. This collection schedule can be extended up to two weeks. Samples are then analyzed for the precise amount of deuterium and 18O excreted at each time-point. These numbers can be used to calculate total body water turnover. Because O2 in body water is in complete equilibrium with respiratory CO2, water turnover can be used to calculate CO2 production, which can be used to calculate energy expenditure. This process of collection over the course of 7-14 days allows investigators to measure the free living total daily energy expenditure of their study participants.
Analysis of DLW Data
Once the isotope concentration in the biological samples has been determined, the numbers run through a series of calculations to convert to Total Daily Energy Expenditure in calories. Historically, labs created spreadsheets to run the calculations. However, due to variability in spreadsheets, Dr. Melanson and his colleagues in the DLW field have developed a web program to run the DLW calculations. The program is accessible by clicking the button below.
Current Studies the DLW Core Supports
NIH Funded Trials
DRIFT 2 (R01DK111622 - PI: Catenacci) - The primary aim of this study is to compare the effects of Intermittent Fasting (IMF) versus Daily Caloric Restriction (DCR) on changes in body weight and body composition after 12 months. DLW is being used to measure energy intake using the intake-balance method.
Sleep Restriction (R01HL128226 - PI: St. Onge) - The primary aim of this study is to evaluate the effect of long-term sleep restriction on energy balance. DLW is being used to measure free-living total daily energy expenditure (TDEE).
ARROW (R01DK114272 - PI: Bessesen) - The primary aim of this study is to evaluate adaptive responses to overeating in adults who have lost weight. DLW will be used to measure TDEE following weight loss and at one year of follow-up.
STRATH (R01CA215318 - PI: Strath) - primary aim of this study is to evaluate and refine machine learned accelerometer algorithms to predict energy cost and activity type in functionally limited populations. After algorithms are optimized during a 24h whole-room calorimetry visit the algorithms will be validated under free-living conditions using DLW.
Breath(R21DK113401 - PI: Melanson) - The primary aim of this study is to compare natural abundances of water isotopes in human breath, saliva, and urine.
WLM (K01HL145023 - PI: Creasy) - The primary aim of this study is to evaluate patterns of energy intake, physical activity, and sleep in a cohort of individuals who participated in an 18-month behavioral weight loss intervention. DLW will be used to measure TDEE at 3 years of follow-up.
GLYDE (F32DK116402 - PI: Creasy) - The primary aim of this study is to compare the effects of moderate versus vigorous intensity exercise training on indices of glycemic control in older adults with prediabetes after 12 weeks. DLW is being used to measure TDEE pre- and post intervention.
Other Funded Trials
FYI (PI: Tang) - A randomized controlled feeding trial of infant growth, gut microbiota and sleep behaviors during early complementary feeding.
NAME (PI: Vetter) - The primary aim of this study is to examine the association between circadian misalignment and energy expenditure in free-living shift workers. DLW will be used to measure TDEE.
NAME (PI: Depner) - The primary aim of this study is to assess the impact of increasing sleep by ≥2h/night for 4 weeks on energy intake and energy expenditure. DLW will be used to measure TDEE pre- and post intervention.