Metabolic Solutions offers project design assistance and stable isotope analysis services to help researchers determine energy expenditure using the doubly labeled water stable isotope method. Stable isotopes of hydrogen (deuterium oxide) and oxygen (oxygen 18) are routinely used to measure energy expenditure in free-living humans or field metabolic studies in animals.
The doubly labeled water method is a form of indirect calorimetry that has been extensively validated in animals and humans. The method is completely safe, requires only periodic sampling of body fluids (plasma, urine, saliva), is non-restrictive, and is ideally suited for measurement of energy expenditure in free-living or hospitalized patients.
A typical energy expenditure study protocol using the doubly labeled water method starts with a baseline plasma, saliva or urine collection to determine pre-dose values for the hydrogen and oxygen isotopes. The subject is given a single oral bolus dose of heavy water (2H218O). Generally, adults are given a dose consisting of 0.15 g H218O/kg body weight and 0.06 g 2H2O/kg body weight. Children and neonates are given higher doses per kilogram due to their faster water turnover rates. Additional samples are collected 1 to 2 weeks later. We offer sensitive methods for measuring deuterium and oxygen-18 levels in plasma, urine or saliva with 15-25 µl of sample. If you are interested in small animal energy expenditure studies, please visit our latest advances.
Please contact us with your questions about DLW protocols or stable isotope analysis of body fluids.
Stable Isotope Analysis Applications
|Total daily energy expenditure||Middle-age women and men||Total daily energy expenditure: OPEN Study|
|Weight loss studies||Adults||Long-term effects of energy-restricted diets|
|Total daily energy expenditure||Children||Energy expenditure predicts changes in body fat in children|
|Comparisons of food frequency questionnaires||Adults||Accuracy of dietary assessment methods|
|Total daily energy expenditure||Small animals||DLW studies in mice|
|Field metabolic studies||Animals||Field metabolic rate and body size|
Research, validation studies, procedures and technical information for measuring energy expenditure with the doubly labeled water method can be obtained in our technical paper: Energy Expenditure using Doubly Labeled Water.