Background: Chronic complications (e.g. cardiovascular failure) are among the most common problems in diabetics. It is suggested that oxidative stress and lipid peroxidation play a key role in chronic diabetic complications. Supplementation with agents containing antioxidant properties can suppress lipid peroxidation. Many studies confirmed the antioxidant properties of zinc in biological systems. The aim of the present study was to evaluate the effect of zinc supplements on serum lipid oxidizability in diabetic patients.

Materials and Methods: In this clinical trial study, 60 diabetic patients were chosen and randomly divided into two groups. Serum lipid oxidizability and serum zinc level were evaluated in each group before and after zinc supplementation (25.50 mg/day for 2 month). Lipid oxidizability was followed through monitoring the change of conjugated compounds in diluted serum after adding Cu²⁺ by spectrophotometric method. S erum zinc level was measured by atomic absorbance spectrophotometer.

Results: While there was no significant change in the post- supplementation zinc level (25 mg) in the first group, zinc serum level was increased significantly (p<0.002) in the second group. No significant change was seen in serum lipid oxidizability parameters before and after supplementation in two groups. SPSS software (V.11.5) and Wilcoxon test were used for statistical analysis.

Conclusion: Our results indicate that zinc supplementation (25.50 mg) in short period of time has no favorable effect on serum lipid oxidizability in diabetic patients. It seems that zinc dose, duration of treatment and also the patients' condition may affect their response to supplementation.