Anorexia of Ageing

Anorexia of ageing is the physiological fall in appetite and food intake that occurs with advancing age. It is a risk factor for weight loss, sarcopenia, frailty and malnutrition.

About 15% to 30% of community dwelling older adults report reduced appetite, and rates are higher in hospital and care homes.

Pathophysiology. Reduced gastric fundal relaxation causes early satiety. Higher levels of satiety signals (cholecystokinin, leptin, peptide YY) and lower ghrelin dampen hunger. Declining taste and smell, slower gastric emptying and lower energy expenditure add to the effect. Illness, depression, drugs and poor dentition worsen it.

Early fullness, small meal sizes, skipped meals, reduced interest in food and gradual weight loss, usually with loss of muscle. Other causes of poor intake may coexist.

Diagnosis is clinical, by exclusion of pathology. Use a validated short appetite questionnaire together with weight records and a food diary. Check full blood count, inflammatory markers, urea and electrolytes, calcium, glucose, thyroid function, liver tests and zinc if taste is lost. Assess mood, cognition, dentition and swallowing.

Differential diagnosis.

• Depression and dementia.
• Malignancy, chronic infection and chronic organ failure.
• Medicine effects and constipation.
• Dysphagia and dental disease.

Offer small, frequent, energy dense, fortified meals and snacks, eaten with others where possible, with flavour enhancement. Remove unnecessary dietary restrictions. Use oral nutritional supplements between meals, not instead of meals. Stop or switch drugs that suppress appetite, treat constipation and depression, and provide dental and eating assistance. Mirtazapine 7.5 to 15 mg at night is reasonable only when depression is present.

Monitoring. Weight monthly, with a nutrition review after any change.