Chemotherapy-Induced Taste Impairment in Patients with Head and Neck Cancer: Molecular Mechanisms and Dietary Prevention

Patients with advanced head and neck cancer often experience dysgeusia as an adverse effect during chemoradiotherapy. Chemoradiotherapy-induced dysgeusia leads to malnutrition, which is a strong independent predictor of survival in patients with head and neck cancer. We found that chemotherapy specifically changed the gene expressions of T1R3 and T2R5 in the lingual mucosa, resulting in impairment of both umami and sweet tastes, and phantogeusia. The monosodium salt of L-glutamate (monosodium glutamate, MSG) is an umami compound that is used as a seasoning around the world. We examined the effects of dietary supplementation with MSG on chemotherapy-induced downregulation of T1R3 gene expression in the tongues of patients with head and neck cancer receiving chemoradiotherapy. MSG supplementation suppressed chemotherapy-induced dysgeusia by inhibiting chemotherapy-induced downregulation of T1R3 gene expression in the tongue, resulting in an increase of energy intake in the patients. Thus, dietary supplementation with MSG during CRT may be a promising nutritional intervention to improve the prognosis of patient with head and neck cancer.