Body Composition

Mission
The Body Composition Laboratory is focused on developing methods for investigating body composition, energy metabolism, and nutrient status. Accurate body composition measurements are essential for nutrition related research studies and assessment of health status. This laboratory demonstrates particular interest in developing new ways to using stable isotopes to study the details of energy metabolism mechanisms, especially as they relate to obesity, sarcopenia, growth, and weight regulation. In addition, there are continued efforts to identify and validate reliable zinc status biomarkers and additional measures of frailty in at risk populations such as the elderly. Most of the approaches being developed and validated are inexpensive, safe, and appropriate for use in field studies.

Lab Objectives
1. To develop and validate tools and methods for measuring body composition; metabolism and nutrient status for the assessment of energy utilization; health and micronutrient status; and frailty and sarcopenia in both the home dwelling and institutionalized elderly population.

2. To develop, test and validate mathematical models relating to body composition and energy balance measurements that can be of practical use in determining energy intake and regulation, and assessing overall health status.

Measurement Tools and Capabilities
• Determination of body fat in vivo using neutron inelastic scattering (reference method).
• Determination of intracellular mass via total body potassium using gamma ray counting (reference method).
• Development of new analytical methods for field use, such as non-destructive plasma or urine X-ray fluorescence (XRF) analysis for extracellular water and zinc status measurements.
• Development and validation of a hand-held DXA instrument for rapid in vivo measurements of muscle mass.
• Adaptation and validation of new cavity resonance laser absorption technology to replace isotope ratio mass spectrometry for rapid measurements of total body water and energy expenditure (simultaneous analysis of D and O-18).
• Development of innovative stable isotope methods for energy intake assessment using C-13 labeled food and breath tests.
• Use of C-13 kinetics and mathematical modeling to study the details of metabolism and the existence of a regulation “set point” for individuals.

Staff
Joseph J. Kehayias, Ph.D., Laboratory Director
Scientist I and Associate Professor, Nutrition
Research focus: body composition and radioisotope kinetics

Carrie Brown, M.S., Research Assistant
Anna V Roto, B.S., B.S., Graduate Research Assistant
Kristi Kasuli, B.S., Budget & Administrative Assistant

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