Zinc, Copper, and Oxidative Stress in Diabetes: Insights From an Oral Glucose Tolerance Test Study

INTRODUCTION: Zinc (Zn) and copper (Cu) play important roles in glucose metabolism and redox balance. This study evaluated serum Zn Cu and oxidative stress markers during an oral glucose tolerance test and examined their relationships with glucose dynamics.
METHODS: We studied 195 adults including 138 healthy controls and 57 individuals with newly diagnosed diabetes. Blood samples were obtained at baseline T0 at 60 min T1 and at 120 min T2. Glucose insulin Zn Cu total oxidant status (TOS) and related biochemical parameters were measured. Between group comparisons were performed and correlation heatmaps were presented descriptively.
RESULTS: Glucose levels were higher in the diabetes group than in controls at T1 and T2 with p<0.001. At T1 zinc was higher in patients than in controls 84.14 versus 77.95 mcg/dL with (p=0.010) while groups were similar at baseline and at T2. Cu declined after the glucose load in both groups. TOS was lower during the test in both groups in a descriptive manner and between group differences were not significant at any time point. Lipid profile insulin cortisol and Homeostatic Model Assessment of Insulin Resistance did not differ significantly between groups. Correlation patterns suggested more stable relationships in controls and weaker more variable links among trace elements and oxidative markers in diabetes.
DISCUSSION AND CONCLUSION: Glucose dysregulation was evident in diabetes whereas trace element and oxidative stress responses to the glucose challenge were modest. The higher zinc level at T1 in patients may reflect short term mobilization or redistribution. These findings support the need for longitudinal and interventional studies to clarify the roles of Zn and Cu in dysglycemia and to assess the translational value of dynamic trace element measurements.

Keywords: Copper, diabetes mellitus, oral glucose tolerance test, oxidative stress, zinc.