Altered taste perception in Type 2 Diabetes Mellitus: A case-control study on taste thresholds and glycemic control

Background and objectives: Diabetes Mellitus (DM) is associated with altered taste perception, often leading to cravings for carbohydrate-rich foods. Although taste dysfunction has been linked to diabetic neuropathy, this association is debatable. Few studies have evaluated taste thresholds in individuals with diabetes, necessitating further investigations. This study aimed to assess gustatory function in patients with Type 2 Diabetes Mellitus (T2DM). Materials and methods: A total of 138 participants were included in the study: 46 with controlled T2DM, 46 with uncontrolled T2DM, and 46 healthy controls. Taste perception was assessed using whole-mouth threshold and spatial tests. Data were analysed using the Kruskal-Wallis test, followed by Dunn-Bonferroni post hoc tests for pairwise comparisons. The significance level (p) was set at 0.05 for all statistical analyses. Results: HbA1c levels were highest in the non-controlled diabetes group (11.22%), followed by the controlled DM group (7.43%) and the control group (5.08%) (p < 0.001). Whole-mouth threshold and spatial taste tests showed significant taste impairment in patients with diabetes, worsening with poor glycaemic control (p < 0.001), particularly for sweet, sour, and bitter tastes. Salt perception was unaffected (p = 0.56). Conclusion: Individuals with diabetes exhibit taste dysfunction, particularly for sweet, sour, and bitter tastes. Blunted sweet perception may lead to increased sugar intake, worsening hyperglycaemia. These findings highlight the need for dietary counselling to mitigate the impact of taste impairment on glycaemic control.