The
Doubly-labelled Water Method for Measuring Energy Expenditure: A consensus Report by the
IDECG working groupThe
Doubly-labelled Water Method for Measuring Energy Expenditure: A consensus Report by the
IDECG working groupTechnical recommendations for use in humans
Editor: AM Prentice
I/D/E/C/G International Dietary Energy Consultancy Group
INTERNATIONAL ATOMIC ENERGY AGENCY
NAHRES-4, IAEA, Vienna (1990)
Contributing authors:
TJ Cole
WA Coward
M Elia
CJ Fjeld
M Franklin
MI Goran
P Haggarty
KA Nagy
AM Prentice
SB Roberts
DA Schoeller
K Westerterp
WW Wong
Single copies of this report are available on request, free of charge, from:
Section of Nutritional and Health-Related Environmental Studies
International Atomic Energy Agency
P.O. Box 100, A-1400, Vienna, Austria
NATHAN LIFSON 1911-1989
This book is dedicated to the memory of Nathan Lifson, inventor of the doubly-labelled water method, who sadly died on 31st December 1989.
The digitalization of this publication was made possible by a grant from the Nestlé Foundation
Participants in the IDECG Workshop
1.1 Significance
1.2 Principle of the doubly-labelled water method
1.3 Origin of the method
1.4 Development
1.5 Small animal studies
1.6 Human studies
1.7 Human validation studies
1.8 Purpose of the Cambridge workshop
1.9 References
Chapter 2: Recommended abbreviations
Chapter 3: Mass spectrometric analysis
3.1. History
3.2 Sample requirements
3.3 Isotope ratio measurements
3.4 Water standards
3.5 Sample preparation
3.6 Mass spectrometer accessories
3.7 Required precision of isotopic analyses
3.8 Sources of 2H- and 18O-labelled water
3.9 Preparation of water tracer for human consumption
3.10 Deuterium and 18O enrichments of the dose
3.11 Concluding remarks
3.12 References
Chapter 4: Calculation of pool sizes and flux rates
4.1 Introduction
4.2 The basic model
4.3 Calculation of pool sizes
4.4 Calculation of flux rates
4.5 References
5.1 Types of error
5.2 Variance and covariance
5.3 Ratio plots and product plots
5.4 The variance of CO2 production
5.5 Optimal design to minimise the variance
5.6 Variance and the two-point method
5.7 Bias in the estimation of pool size
5.8 Precision and accuracy in the multi-point and two-point methods
5.9 Constancy of errors
5.10 Data and residual plots
5.11 References
Chapter 6: Isotope fractionation corrections
6.1 Isotope fractionation
6.2 Experimental determinations of fractionation factors in vivo
6.3 Incorporation into calculations
6.4 Potential errors in rCO2
6.5 Estimation of fractionated water loss
6.6 References
Chapter 7: The effect of isotope sequestration and exchange
7.1 Isotope incorporation into tissue and its effect on the DLW technique
7.2 The stoichiometry of sequestration
7.3 The effect of sequestration on the performance of DLW
7.4 Export of exchangeable hydrogens
7.5 The effect of sequestration/exchange on related techniques
7.6 Summary and conclusions
7.7 References
Chapter 8: Changes in isotopic background
8.1 All water is not created equal
8.2 Observed baseline changes
8.3 Model of isotopic abundance of body water
8.4 Use of doubly-labelled water under conditions of changing baseline
8.5 References
Chapter 9: Practical consequences of deviations from the isotope elimination model
9.1 Assumptions and the model
9.2 Systematic changes in isotopic turnover
9.3 Random error in the isotopic enrichment
9.4 Summary of theoretical comparison of methods
9.5 Practical comparisons of the two-point and slope-intercept methods
9.6 Conclusions
9.7 References
Chapter 10: Converting carbon dioxide production to energy expenditure
10.1 Introduction
10.2 Estimating EeqCO2 for different oxidation mixtures
10.3 Adjusting EeqCO2 for nutrient imbalance in the subject
10.4 References
Chapter 11: Practical recommendations and worked examples
11.1 Choice of two-point or multi-point technique
11.2 Procedure for calculating two-point data
11.3 Procedure for calculating multi-point data
11.4 Practical hints
11.5 References
Chapter 12: Recommendations for data presentation in publications
Chapter 13: Use of the doubly-labelled water method under difficult circumstances
13.1 General considerations
13.2 Use of the doubly-labelled water method in infants
13.3 Application of the doubly-labelled water method at high activity levels
13.4 Application of DLW under tropical conditions
13.5 Application of DLW in non-compliant subjects
13.6 Application of DLW in clinical situations
13.7 References
Appendix 1: A brief introduction to kinetic studies with tracers
App 1.1: Single pool systems
App 1.2: Systems with two or more pools
Appendix 2: Development of equations for calculating pool sizes from isotope dilution
App 2.1: Development of equations for calculating pool sizes from isotope dilution
App 2.2: References
Appendix 3: Derivation of a general equation to cope with changes in pool space
App 3.1: Basic derivation
App 3.2: A general solution to equation 2
App 3.3: Estimating CO2 production
App 3.4: The shape of the enrichment curve
App 3.5: References
Appendix 4: Further comments on estimating water flux and CO2 production
App 4.1: Modelling enrichment data
App 4.2: The effect of auto-correlated errors on linear regression
Appendix 5: Determination of optimal dosing ratios
App 5.1: Background
App 5.2: Derivation of a formula to predict optimal dose ratios
App 5.3: Practical consequences
App 5.4: Reference