Effects of expectancy, food preference and time of day on salivation in cancer patients
The purpose of the present study was to study differences between cancer patients and noncancer patients in taste acuity and in salivation to food and stimuli associated with food. Subjects were twenty male cancer patients and eighteen patients hospitalized for noncancer-related illnesses. All cancer patients were tested prior to chemotherapy or radiation therapy.
The study was conducted on two consecutive days. On Day 1 taste acuity was measured to bitter, sweet, sour and salty flavors using the forced choice three-stimulus drop technique on concentration from 6-2000 mm/l. Subjects completed a questionnaire on appetite difficulties, the Multiple Adjective Affect Check List (MAACL), and rated a list of snacks on a 5-point scale. On Day 2 salivary responding (using the Strongin-Hinsie Peck Test) was measured after subjects were told to expect food, after the presentation of food and after ingestion. For each subject, testing occurred in the morning and in the afternoon to high and low preferred foods.
Cancer patients were significantly more likely than noncancer patients to report appetite difficulties which included premature satiety, decreased appetite, and changes in food preference. Cancer and noncancer patients did not differ reliably on the MAACL or in taste acuity. In salivation testing, the presentation of food increased salivation in noncancer patients but decreased salivation in cancer patients. However, the differences between cancer and noncancer patients was not reliable. The interaction between illness condition and test trials during the presentation of food did approach significance.
The lack of reliable effects for illness condition may have occurred because the interval of food deprivation was too short to elicit reliable increases in salivation and external and social cues which normally accompany mealtime were not present during testing.