Olfaction in Palliative Care Patients

Smell and taste play a role in appetite, food choices, and nutrient intake for the following reasons: First, these chemosensory signals prepare the body to digest food by triggering salivary, gastric, pancreatic, and intestinal secretions which are termed cephalic phase responses. Second, they enable us to detect and discriminate between foods in the face of fluctuating nutritional requirements. Third, they enable selection of a nutritious diet. Learned associations between a food’s smell and taste and its postingestive effects enable the consumer to modulate food intake in anticipation of its nutritional consequences. Fourth, taste and smell signals initiate, sustain and terminate ingestion, and hence play a major role in the quantity of food that is eaten and the size of meals. Fifth, taste sensations induce feelings of satiety and are primary reinforcers of eating. Thus, chemosensory impairments can alter food choices and intake and subsequently exacerbate disease states (Table 19.1).