HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hsu, A. Articles by Gallagher, D. Search for Related Content PubMed PubMed Citation Articles by Hsu, A. Articles by Gallagher, D. Agricola Articles by Hsu, A. Articles by Gallagher, D.

Larger mass of high-metabolic-rate organs does not explain higher resting energy expenditure in children^1,2,3

¹ From the Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University (AH, SH, M-YS, and DG), the Obesity Research Center (SH, IJ, M-YS, and DG), the Children’s Hospital of New York (MH), and the Department of Cardiology, St Luke’s–Roosevelt Hospital (NK), New York.

Background: Children have a high resting energy expenditure (REE) relative to their body weight. The decline in REE during growth may be due to changes in body composition or to changes in the metabolic rate of individual organs and tissues.

Objectives: The goals were to quantify body-composition components in children at the organ-tissue level in vivo and to determine whether the observed masses 1) account for the elevated REE in children and 2) account, when combined with specific organ-tissue metabolic constants, for children’s REE.

Design: This was a cross-sectional evaluation of 15 children (aged 9.3 ± 1.7 y) and 13 young adults (aged 26.0 ± 1.8 y) with body mass indexes (in kg/m²) < 30. Magnetic resonance imaging–derived in vivo measures of brain, liver, kidney, heart, skeletal muscle, and adipose tissue were acquired. REE was measured by indirect calorimetry (REE_m). Previously published organ-tissue metabolic rate constants were used to calculate whole-body REE (REE_c).

Results: The proportion of adipose-tissue-free mass as liver (3.7 ± 0.5% compared with 3.1 ± 0.5%; P < 0.01) and brain (6.2 ± 1.2% compared with 3.3 ± 0.9%; P < 0.001) was significantly greater in children than in young adults. The addition of brain and liver mass significantly improved the model but did not eliminate the role of age. REE_c with published metabolic coefficients underestimated REE_m (REE_c = 3869 ± 615 kJ/d; REE_m = 5119 ± 769 kJ/d; P < 0.001) in children.

Conclusion: The decline in REE during growth is likely due to both a decrease in the proportion of some of the more metabolically active organs and tissues and changes in the metabolic rate of individual organs and tissues.

Key Words: Organ mass • fat-free mass • resting energy expenditure • magnetic resonance imaging • growth • children

This article has been cited by other articles:

				A. Bosy-Westphal, E. Kossel, K. Goele, W. Later, B. Hitze, U. Settler, M. Heller, C.-C. Gluer, S. B Heymsfield, and M. J Muller Contribution of individual organ mass loss to weight loss-associated decline in resting energy expenditure Am. J. Clinical Nutrition, October 1, 2009; 90(4): 993 - 1001. [Abstract] [Full Text] [PDF]

				W. Later, A. Bosy-Westphal, B. Hitze, E. Kossel, C-C Gluer, M. Heller, and M. J Muller No evidence of mass dependency of specific organ metabolic rate in healthy humans Am. J. Clinical Nutrition, October 1, 2008; 88(4): 1004 - 1009. [Abstract] [Full Text] [PDF]

				N. F. Butte, M. R. Puyau, F. A. Vohra, A. L. Adolph, N. R. Mehta, and I. Zakeri Body Size, Body Composition, and Metabolic Profile Explain Higher Energy Expenditure in Overweight Children J. Nutr., December 1, 2007; 137(12): 2660 - 2667. [Abstract] [Full Text] [PDF]

				J. Kim, W. Shen, D. Gallagher, A. Jones Jr, Z. Wang, J. Wang, S. Heshka, and S. B Heymsfield Total-body skeletal muscle mass: estimation by dual-energy X-ray absorptiometry in children and adolescents. Am. J. Clinical Nutrition, November 1, 2006; 84(5): 1014 - 1020. [Abstract] [Full Text] [PDF]

				I. Zakeri, M. R. Puyau, A. L. Adolph, F. A. Vohra, and N. F. Butte Normalization of Energy Expenditure Data for Differences in Body Mass or Composition in Children and Adolescents J. Nutr., May 1, 2006; 136(5): 1371 - 1376. [Abstract] [Full Text] [PDF]

				Z. Wang, S. Heshka, S. B Heymsfield, W. Shen, and D. Gallagher A cellular-level approach to predicting resting energy expenditure across the adult years Am. J. Clinical Nutrition, April 1, 2005; 81(4): 799 - 806. [Abstract] [Full Text] [PDF]