CHAPTER 7 ● ● Unintended Weight Loss

Unintended weight loss (UWL) in the older adult is a harmful occurrence that should be prevented if at all possible. Risk factors for UWL can be classified into three main categories (1): ●

Physiological: (pressure ulcers/nonhealing wounds, loss of strength leading to falls, hip frac- tures, dehydration, infection, immune dysfunc- tion, and anemia);

Psychological: (depression, dementia, anxiety, anorexia nervosa, and bereavement); and

Social: (poverty, isolation, needing help with meals).

In addition, advancing age may be linked with a progression of physiological changes such as loss of teeth, lower nutrient absorption, and change in the senses of taste and smell, as well as a basal metabolic rate (BMR) decline of 2% with each decade of life and a lean body mass (LBM) decline with each decade of life (2,3).

Nutrition diagnosis of UWL is often linked with an underlying illness, progressive disability, increased morbidity, and mortality, all of which have adverse consequences. Clinicians report that in 1 in 4 older adults with UWL, no obvious cause can be identified (4). UWL in the older adult affects 13% of ambulatory residents/clients and 50% to 60% of nursing facility residents/clients (5). Nutrition and dietetics practi- tioners working in extended care and assisted-living facilities, home care, and rehabilitation centers find UWL to be one of the most challenging clinical prob- lems facing adults 65 and over. UWL can be categorized into one of three primary etiologies: starvation, sarcopenia, and cachexia (6).

Starvation: This is the most extreme form of maras- mus and is a consequence of partial or total lack of essential nutrients for a long time. Starvation can lead to cachexia, but that is usually not as common. It

results in a loss of body fat and nonfat mass due to inadequate intake of protein and energy and is linked to decreased energy needs, declining metabolic rate, and activity level (7). The key physiological sign of starvation is that it is reversed solely by the replenish- ment of nutrients.

Sarcopenia: This is defined as the loss of skeletal muscle mass and quality, which accelerates with aging and is associated with functional decline. At present, no known etiology has been identified, but multiple factors appear to contribute to its development. Sarcopenia occurs in 5% to 13% of those over age 70 and is a precursor to disability and increased mortality (8). Sarcopenia is part of a vicious cycle that can result in a reduction in overall skeletal muscle mass, as muscle atrophy takes place with normal aging and leads to reduced strength and exercise capacity (9,10). Other factors such as inactive lifestyles and inadequate protein and energy intakes exaggerate muscle fiber atrophy. Inflammation due to chronic disease triggers the release of proinflammatory cytokines, including tumor necrosis factor (TNF), interleukin-1, and inter- leukin-6; these are reported to be higher in aging adults and may be linked with early satiety, muscle wasting, and increased resting energy expenditures (11). Loss of muscle strength and function associated with sarcope- nia is a hallmark of frailty among the elderly (12). Diminished muscle function in the frail elderly is part of a multisystem approach to aging that leads to progressive disability (13). Not all sarcopenic persons have a low body mass. The term sarcopenic obesity has been defined for those obese persons with muscle loss resulting from disease or disuse. In this situation, the reduced muscle mass is replaced by an increase in fat stores (14). Excess energy intake, physical inactiv- ity, low-grade inflammation, insulin resistance, and changes in hormonal milieu, as well as peptides pro- duced by adipose tissue, may play an important role in