TY - JOUR
T1 - Differences between brain mass and body weight scaling to height
T2 - Potential mechanism of reduced mass-specific resting energy expenditure of taller adults
AU - Heymsfield, Steven B.
AU - Chirachariyavej, Thamrong
AU - Rhyu, Im Joo
AU - Roongpisuthipong, Chulaporn
AU - Heo, Moonseong
AU - Pietrobelli, Angelo
PY - 2009/1
Y1 - 2009/1
N2 - Adult resting energy expenditure (REE) scales as height ̃1.5, whereas body weight (BW) scales as height ̃2. Mass-specific REE (i.e., REE/BW) is thus lower in tall subjects compared with their shorter counterparts, the mechanism of which is unknown. We evaluated the hypothesis that high-metabolic-rate brain mass scales to height with a power significantly less than that of BW, a theory that if valid would provide a potential mechanism for height-related REE effects. The hypothesis was tested by measuring brain mass on a large (n = 372) postmortem sample of Thai men. Since brain mass-body size relations may be influenced by age, the hypothesis was secondarily explored in Thai men age ≥45 yr (n = 299) and with brain magnetic resonance imaging (MRI) studies in Korean men (n = 30) age ≤20<30 yr. The scaling of large body compartments was examined in a third group of Asian men living in New York (NY, n = 28) with MRI and dual-energy X-ray absorptiometry. Brain mass scaled to height with a power (mean ± SEE; 0.46 ± 0.13) significantly smaller (P < 0.001) than that of BW scaled to height (2.36 ± 0.19) in the whole group of Thai men; brain mass/BW scaled negatively to height (-1.94 ± 0.20, P < 0.001). Similar results were observed in younger Thai men, and results for brain mass/BW vs. height were directionally the same (P = 0.09) in Korean men. Skeletal muscle and bone scaled to height with powers similar to that of BW (i.e., ̃2-3) in the NY Asian men. Models developed using REE estimates in Thai men suggest that brain accounts for most of the REE/BW height dependency. Tall and short men thus differ in relative brain mass, but the proportions of BW as large compartments appear independent of height, observations that provide a potential mechanistic basis for related differences in REE and that have implications for the study of adult energy requirements.
AB - Adult resting energy expenditure (REE) scales as height ̃1.5, whereas body weight (BW) scales as height ̃2. Mass-specific REE (i.e., REE/BW) is thus lower in tall subjects compared with their shorter counterparts, the mechanism of which is unknown. We evaluated the hypothesis that high-metabolic-rate brain mass scales to height with a power significantly less than that of BW, a theory that if valid would provide a potential mechanism for height-related REE effects. The hypothesis was tested by measuring brain mass on a large (n = 372) postmortem sample of Thai men. Since brain mass-body size relations may be influenced by age, the hypothesis was secondarily explored in Thai men age ≥45 yr (n = 299) and with brain magnetic resonance imaging (MRI) studies in Korean men (n = 30) age ≤20<30 yr. The scaling of large body compartments was examined in a third group of Asian men living in New York (NY, n = 28) with MRI and dual-energy X-ray absorptiometry. Brain mass scaled to height with a power (mean ± SEE; 0.46 ± 0.13) significantly smaller (P < 0.001) than that of BW scaled to height (2.36 ± 0.19) in the whole group of Thai men; brain mass/BW scaled negatively to height (-1.94 ± 0.20, P < 0.001). Similar results were observed in younger Thai men, and results for brain mass/BW vs. height were directionally the same (P = 0.09) in Korean men. Skeletal muscle and bone scaled to height with powers similar to that of BW (i.e., ̃2-3) in the NY Asian men. Models developed using REE estimates in Thai men suggest that brain accounts for most of the REE/BW height dependency. Tall and short men thus differ in relative brain mass, but the proportions of BW as large compartments appear independent of height, observations that provide a potential mechanistic basis for related differences in REE and that have implications for the study of adult energy requirements.
KW - Body composition
KW - Nutritional requirements
UR - http://www.scopus.com/inward/record.url?scp=58649124751&partnerID=8YFLogxK
U2 - 10.1152/japplphysiol.91123.2008
DO - 10.1152/japplphysiol.91123.2008
M3 - Article
C2 - 19008483
AN - SCOPUS:58649124751
SN - 8750-7587
VL - 106
SP - 40
EP - 48
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 1
ER -