Alterations in emotional responses (pleasantness/unpleasantness) induced by sniffing food odors during chemotherapy in patients with lung cancer

Abstract

Background: Patients receiving chemotherapy experience anorexia and food aversion in their daily lives, and one of the causes is the smell of food. However, it is not clear why the aversion to these smells occurs. This study aimed to determine the emotional responses of patients when they sniff representative food odors during chemotherapy and to investigate factors influencing smell-induced food aversion. Methods: The subjects were 26 patients with lung cancer undergoing chemotherapy with carboplatin. A visual analog scale (VAS) was used to evaluate whether they felt unpleasantness, with a focus on nizakana (simmered fish) and citrus fruits odors. This evaluation was performed both before and 2 days after the patients were administered carboplatin. Results: The results revealed that the VAS scores of emotional responses due to the sniffing of each food sample did not differ significantly (P = 0.942) before and during chemotherapy. However, the smell of nizakana with added ammonia altered VAS scores of the emotional responses significantly during chemotherapy (P = 0.015). Moreover, patients with lung cancer who had a heightened level of odor awareness in their daily lives felt more unpleasantness by sniffing nizakana with added ammonia (correlation coefficient [rs] = −0.437, P = 0.026). However, patients with a lower odor awareness level felt no unpleasantness. Conclusions: The present findings suggest that patients with food aversion during chemotherapy are those with heightened odor awareness level; furthermore, this happens when they sense smells characteristic of substances harmful to the body.