Taste–taste associations in chemotherapy-induced subjective taste alterations: findings from a questionnaire survey in an outpatient clinic

Purpose Chemotherapy-induced taste alteration is a side effect that can result in malnutrition and reduced quality of life in cancer patients. However, the underlying causes of this phenomenon remain unclear, and evidence-based treatments have not been established. This study focused on patients’ subjective symptoms of taste alterations aimed to explore how the sensitivity to basic tastes changes due to anticancer agents and how alterations in one taste perception are associated with changes in other tastes during chemotherapy. Methods A cross-sectional questionnaire-based interview survey was conducted on 215 patients undergoing chemotherapy. The subjective sensitivity to each basic taste was assessed using a visual analog scale, and the incidence of taste alterations due to different chemotherapy regimens was calculated. Multivariate logistic regression analysis was performed to determine whether there were associations between changes in one taste sensitivity and changes in other taste sensitivities. Results Approximately half (49.5%) of the patients experienced chemotherapy-induced taste alterations. An analysis of subjective changes in basic tastes revealed that the salt and umami taste systems were more sensitive to chemotherapy than other taste systems. Patients with altered sensitivity to sweet taste were significantly more likely to report altered sensitivity to salt, bitter, and sour tastes. Moreover, umami–salt and bitter–sour taste sensitivities were significantly related to each other. Conclusion This study suggests that changes in subjective sensitivities to one basic taste during chemotherapy may be accompanied by changes in other tastes in specific combinations. Considering taste associations in dietary guidance may help improve the nutritional status of cancer patients experiencing taste alterations due to chemotherapy.