The effect of dietary treatment on lipid peroxidation and antioxidant status in newly diagnosed noninsulin dependent diabetes.

Increased lipid peroxidation and reduced antioxidant status may contribute to the development of complications in diabetes. The aim of this study was to assess the effects of dietary treatment of noninsulin-dependent diabetes on these parameters. Twenty patients with newly diagnosed noninsulin-dependent diabetes were recruited along with 20 age, sex, and smoking-status-matched control subjects. Dietary intake was assessed by food frequency questionnaire and 24-h dietary recall and blood collected for biochemical analyses before and 2 months after dietary treatment was initiated. Carbohydrate, fat, and protein intake fell in patients following dietary advice. Among micronutrients, intakes of vitamins C, E, and A, carotene, selenium, copper, zinc, and iron were similar in patients and controls. Vitamin C intake in patients rose following dietary advice (44.6 +/- 11.7 vs. 49.5 +/- 5.5 mg/d, p < .05), while there was no change in intake of other micronutrients. Fasting plasma glucose in diabetic subjects fell from 13.6 +/- 1.1 mmol/l at recruitment to 9.7 +/- 1.1 mmol/l after diet (p < .01), and this was accompanied by a fall in hemoglobin Alc from 7.44 +/- 0.67% to 5.91 +/- 0.57% (p < .01). Serum malondialdehyde was higher in patients than controls at T0 (2.39 +/- 0.55 mumol/l vs. 1.48 +/- 0.33; p < .01), and fell following diet to 1.42 mumol/l (p < 0.01). Ascorbate was lower in patients than controls (1.27 +/- 2.9 mumol/k vs. 41.4 +/- 9.3; p < .01) at baseline and rose after diet to 27.8 +/- 6.4 (p < .01). beta-Carotene also rose after diet in patients (0.13 +/- 0.04 mumol/l vs. 0.17 +/- 0.04; p < 0.05), as did lipid corrected alpha-tocopherol (4.39 +/- 1.09 mumol/mmol cholesterol vs. 5.16 +/- 1.18; p < .05). Reduced lipid peroxidation and improved antioxidant status may be one mechanism by which dietary treatment contributes to the prevention of diabetic complications.