An evaluation of oxidative stress in diabetes mellitus during uncontrolled and controlled state and after vitamin E supplementation

Abstract

Objective: The study was conducted on 50 patients (10 insulin dependent diabetes mellitus (IDDM) and 40 non-insulin dependent diabetes mellitus (NIDDM) of recently diagnosed diabetes mellitus. The main objectives of the study were: 1. To evaluate oxidative stress at uncontrolled stage. 2. To evaluate the effect of optimal control on oxidative stress irrespective of type of drug therapy used. 3. To further evaluate the effect of vitamin E supplementation on oxidative stress after achieving optimal control. This was done in order to explore anti-oxidant effect of vitamin E.

Methods: Fifty patients of uncontrolled diabetes of less than 1 year duration and without any overt complications were studied. The parameters of oxidative stress included malonyl-di-aldehyde (MDA), reduced glutathione and vitamin E levels in the blood. They were done at three stages i.e. (a) In uncontrolled stage, (b) At controlled stage and (c) After 4 weeks of vitamin E supplementation in dosage of 400 mg daily. The parameters of control included fasting blood sugar < or = 140 mg%, post prandial < or = 200 mg and HbA1c < or = 7% (analysed by prepared kit).

Results: The significantly raised levels of MDA and decreased levels of reduced glutathione and vitamin E during uncontrolled stage of diabetes indicated free radical stress inducing lipid peroxidation. The significant fall of MDA and rise in reduced glutathione and vitamin E levels in blood after optimal control revealed its beneficial effect on oxidative stress. The levels were not normalised but still stayed higher than controls. After 4 weeks of vitamin E supplementation, further fall in MDA and rise in reduced glutathione suggested beneficial effect of vitamin E over and above the optimal control. Vitamin E estimation in blood at this stage did not constitute parameter of oxidative stress as it was provided from outside but was done to know the compliance of patients. Normalisation or near normalisation was not achieved with vitamin E therapy indicating persistence of oxidative stress.

Conclusion: There was an evidence of oxidative stress in diabetes which decreased with optimal control and further declined after vitamin E supplementation indicating anti-oxidant effect of vitamin E alone. Normalisation of oxidative stress was not achieved. A further study is desired to study the effect of vitamin E for longer period at least 3-6 months before a definite conclusion is drawn.