ABSTRACT
Nutritional considerations playa vital role in human development and successful aging. In addition to affecting longevity, nutritional factors are clearly important in the development of a large number of age-dependent diseases that affect morbidity and mortality. These include atherosclerotic disease, hypertension, neoplasia, and osteoporosis. There is also evidence from animal studies that life expectancy can be significantly extended by restricting food intake. With advancing age, the risk of developing serious nutritional deficiencies also increases. This is related to age-related reductions in total food intake combined with the presence of debilitating disease. The presence of malnutrition increases functional dependency, morbidity, mortality, and utilization of health care resources. This chapter will discuss the relevance of these findings and describe rational approaches to the diagnosis and management of nutritional problems in the elderly.
The only experimental model that has ever been shown to prolong life expectancy is caloric restriction (1-3). In numerous animal models, restriction of total caloric intake by 30% results in significant prolongation in average and maximal life expectancy and retards the appearance of the well-described age-related declines in cell-mediated and humoral immunity (4). The mechanism by which food restriction results in prolongation of life span remains unknown. It appears that total calorie intake is a more important variable than is either total protein or fat intake (5). Caloric restriction results in the presence of leaner and more active animals who utilize energy very efficiently. Overall metabolic requirements are markedly reduced. This lifelong diminution in metabolic activity has recently been suggested as an important factor in prolonging life.
