Aging and body composition: possibilities for future studies.

Three approaches are being taken to the development of techniques for measuring body composition: 1) improving present methods, 2) formulating and devising new body composition measuring techniques and 3) focusing on specific problems of body composition changes in aging. The improvement of multi-frequency bioelectrical impedance, computerized tomography, magnetic resonance and dual-photon absorptiometry imaging belong under the first category. Recent developments in low radiation exposure measurement of body carbon and oxygen by neutron inelastic scattering and body protein by gamma-ray resonance are examples of new technology applied to the direct assessment of body composition of the elderly. The third category remains the most important one and should motivate the evolution of existing methods and the development of new. Current questions focus on distribution of regional body fat and its role in cardiovascular diseases and the depletion of lean body mass with age and its relation to functional capacity, quality of life and resistance to injury or disease. The relationship between the distribution of fat, the depletion of muscle tissue and changes in cellular function with age will become the focus of the future studies of body composition.