The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)


The high metabolic costs of human brain development help explain the unusually slow body growth of human childhood

CHRISTOPHER KUZAWA1,2, HARRY T. CHUGANI3,4,5, LAWRENCE I. GROSSMAN6, LEONARD LIPOVICH5,6, OTTO MUZIK4, PATRICK R. HOF7, DEREK E. WILDMAN6,8, CHET C. SHERWOOD9, WILLIAM R. LEONARD1 and NICHOLAS LANGE10.

1Department of Anthropology, Northwestern University, 2Institute for Policy Research, Northwestern University, 3Positron Emission Tomography Center, Children’s Hospital of Michigan, 4Department of Pediatrics, Wayne State University School of Medicine, 5Department of Neurology, Wayne State University School of Medicine, 6Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, 7Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 8Institute of Genomic Biology and Department of Integrative Physiology, University of Illinois, 9Department of Anthropology, The George Washington University, 10Departments of Psychiatry and Biostatistics, Harvard University and McLean Hospital

March 26, 2015 9:00, Grand Ballroom D Add to calendar

The high energetic costs of human brain development have been hypothesized to explain unique features of the human life history, including slow and protracted pre-adult growth. Although widely assumed to constrain life history evolution, the metabolic requirements of the growing human brain are unknown. We used previously collected PET and MRI data to calculate the human brain’s glucose use from birth to adulthood, which we compare to the rate of body weight growth. We evaluate trade-offs between brain metabolism and body growth using the ratios of brain glucose uptake to the body’s resting metabolic rate (RMR) and daily energy requirements (DER) expressed in glucose-gram equivalents. The ratios of brain glucose-to-RMR or -DER do not peak at birth, when relative brain size is largest, but in childhood, when synaptic densities related to learning are maximal. At 4 years, the brain uses twice the glucose of the adult brain, accounting for the equivalent of 66% of RMR. Consistent with the hypothesis of a brain-body growth trade-off, body weight growth velocity is strongly inversely related to brain glucose demands from infancy until puberty, and maximal brain glucose demand co-occurs with slowest body weight gain. Our quantification of the metabolic costs of the developing human brain support the hypothesis of a trade-off between brain metabolic needs and body weight growth rate. They thus provide rare empirical support for the hypothesis that the slow and protracted growth that characterizes human childhood evolved as compensation for the unusually high glucose requirements of human brain development.

Funding: NSF (BCS-0827546 to DEW); NSF (BCS-0827531 to CS); James S. McDonnell Foundation (220020293 to CS); NIH (Brain Development Cooperative Group: N01 HD023343, N01 MH090002, N01 NS092314 through NS002320; NS034783).