While the impact of age-related alterations in physiology and metabolism has been extensively assessed in pharmacological studies, it has only been within the last two decades that much research has been conducted to define the impact of these changes on human nutritional requirements. The nutrition status of the elderly is also dependent on social conditions and is influenced by the long-term effects of chronic disease and the intake of medication, which can sometimes generate undesired interactions with nutrients. The physiologic changes of aging, including perceptual, endocrine, gastrointestinal, renal, and muscular changes, may affect nutrition needs. Energy needs decrease with age as the result of changes in basal metabolism and physical activity. Basal need are not under the individual's control, but energy expenditure in physical exercise varies according to individual activity patterns.
Physical activity can play a major role in maintaining energy balance.
Sensory impairments that occur with aging may result in consumption of a more monotonous diet. Taste and smeell dysfunction in older adults reveal a progressive decline with age.