Malnutrition or healthy senescence.

There are undeniable changes in the body's composition with old age, and these changes can bring about a plethora of physiological consequences affecting levels of function, and current and subsequent health (Rosenberg, 1989; Heymsfield et al. 1995). Health and function are interrelated states within the ageing process (Nagi, 1976), and transitions amongst them and disease and disability are affected by alterations in the body's composition through the ageing process. The expression and uniformity of changes in body composition vary among healthy, sick and malnourished elderly men and women. This variation affects our interpretation of estimates, measures, indices, and changes in body composition as related to levels of health and function in the elderly. These relationships are further affected by the fact that the elderly of today are some of the first recipients of the improvements in health and nutrition that have occurred during the twentieth century. The present paper reviews some of the issues relating levels of and changes in body composition with health and function among today's elderly. If body composition changes in old age, from what levels are the changes occurring? What is the timing or age at onset of the changes and how appropriate are existing body composition reference data for elderly people today?