can lead to muscle weakness and anorexia; and penicillamine induces zinc depletion that can lead to the loss of taste acuity and decreased food intake. Prescription of a high‐fibre diet may lead to excess satiety.8 More than 250 prescribed medications alter taste, and many others affect smell.80 Overall, older adults often take multiple medications that increase the risk of drug interactions that can cause anorexia.
Conclusion
Anorexia of ageing is associated with impaired muscle function, decreased bone mass, immune dysfunction, anaemia, reduced cognitive function, poor wound healing, delayed recovery from surgery, and ultimately increased morbidity and mortality. Epidemiological studies have demonstrated that protein‐energy malnutrition is a strong independent predictor of mortality in elderly people, regardless of whether they live in the community or a nursing home, are patients in a hospital, or have been discharged from the hospital in the previous one to two years.16 The increased mortality rate in elderly people with protein‐energy malnutrition is further increased in the presence of other medical diseases, such as renal failure, cardiac failure, and cerebrovascular disease. Figure 13.3 illustrates the factors contributing to anorexia as discussed in this chapter.
Figure 13.3 Anorexia as a multifactorial geriatric syndrome with poor outcomes.
Diagnoses and treatment of undernutrition in older people are covered in Chapter 12, ‘Epidemiology of Nutrition and Ageing’, and Chapter 14, ‘Weight Loss’.
Key points
Food intake is less in the elderly than in young adults because of a physiological decrease in appetite: the anorexia of ageing. This predisposes them to the development of protein‐energy malnutrition, a common entity in older adults.
Several additional factors contribute to undernutrition, including physical and physiological changes, chronic disease, environment and other relevant social determinants of health, and iatrogenic causes such as polypharmacy.
Chronic diseases such as dementia, depression, chronic obstructive pulmonary disease, and congestive heart failure can lead to anorexia through various mechanisms.
Activity changes of hormones such as CCK, cytokines, and androgens have been implicated in appetite regulation and the anorexia of ageing.
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