Assessment of body composition, nutritional status, and energy expenditure in the elderly using new analytical methods for stable isotopes

Abstract

A discrete early monitoring system of the nutritional status of the elderly is underdevelopment in our laboratory aiming to preserve quality of life and independence. In the general population obesity or underweight status is commonly assessed by body weight or weight to height measurements. Monitoring the elderly is more complicated. Changes in body composition due to energy imbalance or disease are superimposed on the natural decline in body lean mass with age. Shifts in body weight reflect changes in adipose tissue but may also reflect significant loss in protein mass or changes in tissue hydration. It is the aim of our new program to validate simple inexpensive methods for rapid monitoring of the elderly in their own environment. A series of modern stable isotopemethods are employed to measure body composition, hydration, frailty and energyexpenditure in the field. An important component of this approach is the parallel development of inexpensive analytical devices for the rapid analysis of stable isotopes. Dr. Ribeiro will participate in the development and validation of those methods. She will be able to incorporate this technology in her own research and continuecollaborating with our institution after her return to her university and thus contributingto the systematic study of global nutritional assessment for the better management of the major health issues of our century, such as pediatric and adult obesity, cardiovascular disease, sarcopenia, malnutrition and the special needs of our aging population. Methodology: · Rapid analysis of O-18 and H-2 isotopes using laser absorption methods (forhydration and energy expenditure). · Rapid non-destructive analysis of Br in plasma or urine using X-ray fluorescence (for hydration, extracellular water space and frailty). Use of hand-held DEXA for muscle mass monitoring in the elderly and children (to monitor sarcopenia, cachexia or obesity). (AU)