Dietary supplementation with monosodium glutamate with dietary balance such as protein, salt and sugar intake with increasing T1R3 taste receptor gene expression in healthy females.

We previously showed that chemotherapy-induced dysgeusia was associated with lingual taste receptor gene expression, and monosodium glutamate (MSG) improved dysgeusia by upregulating taste 1 receptor 3(T1R3) gene expression. In recent years, decreased taste sensitivity has also been reported in some young people, and these are partly due to their disordered eating habits. From these background, we investigated the effects of MSG supplementation on taste receptor expression and dietary intake in healthy females. Fifteen young healthy volunteers were enrolled for the present crossover study and divided in two groups (dietary supplementation with MSG at 2.7 g / day or 0.27 g / day). The relative expression of T1R3, a subunit of both umami and sweet taste receptors, in the tongue was assessed by quantitative PCR analysis. Food intake was assessed by food frequency questionnaire (FFQg), and body composition was measured using Omron HBF-701. T1R3 expression levels in the tongue and taste sensitivity increased significantly in participants who consumed <10 g of MSG daily, whereas no alteration was observed in participants who consumed >10 g of MSG daily. Furthermore, protein, fat, and carbohydrate (PFC) balance and salt and sugar intake improved by MSG supplementation. In conclusion, MSG supplementation increased T1R3 expression in the tongue and improved dietary balance. J. Med. Invest. 68 : 315-320, August, 2021.

Dietary Supplementation with Monosodium Glutamate Suppresses Chemotherapy-Induced Downregulation of the T1R3 Taste Receptor Subunit in Head and Neck Cancer Patients.

(Background) We investigated the effect of dietary supplementation with monosodium glutamate (MSG) on chemotherapy-induced downregulation of the T1R3 taste receptor subunit expression in the tongue of patients with advanced head and neck cancer. (Methods) Patients undergoing two rounds of chemoradiotherapy were randomly allocated to a control or intervention group (dietary supplementation with MSG at 2.7 g/day during the second round of chemotherapy). The relative expression of T1R3, a subunit of both umami and sweet taste receptors, in the tongue was assessed by quantitative polymerase chain reaction analysis. Dysgeusia was assessed with a visual analog scale and daily energy intake was evaluated. (Results) T1R3 expression levels in the tongue, taste sensitivity, and daily energy intake were significantly reduced after the first round of chemotherapy compared with before treatment. Furthermore, these parameters significantly decreased after the second round of chemotherapy, but the extent of decrease was significantly attenuated in the MSG group compared with the control group. (Conclusions) MSG supplementation suppresses chemotherapy-induced dysgeusia, possibly due to the inhibition of the T1R3-containing taste receptor downregulation in the tongue, thereby increasing energy intake in patients with advanced head and neck cancer.