THE EFFECT OF DASH DIET ON INSULIN RESISTANCE, INFLAMMATION, AND OXIDATIVE STRESS IN GESTATIONAL DIABETES: A RANDOMIZED CONTROLLED CLINICAL TRIAL

There are no available reports indicating the effects of Dietary Approaches to Stop Hypertension (DASH) eating plan on insulin resistance, inflammation and oxidative stress among pregnant women with gestational diabetes mellitus (GDM) We aimed to investigate the effects of DASH diet on insulin resistance, serum hs-CRP and biomarkers of oxidative stress among pregnant women with GDM. This randomized controlled clinical trial was performed among 32 pregnant women diagnosed with GDM at 24-28 week's gestation. Subjects were randomly assigned to consume either the control (n=16) or DASH diet (n=16) for 4 weeks. The DASH diet was rich in fruits, vegetables, whole grains, and low-fat dairy products and low in saturated fats, total fats, cholesterol, refined grains, and sweets, with a total of 2400 mg/d sodium. The control diet contained 40-55% of its energy as carbohydrates, 10-20% as proteins and 25-30% as total fats. Fasting blood samples were taken at baseline and after 4 weeks of intervention to measure fasting plasma glucose (FPG), serum insulin and hs-CRP, HOMA-IR, plasma total antioxidant capacity (TAC) and total glutathione levels (GSH). Consumption of DASH diet, compared to the control diet, resulted in decreased FPG (-7.62 vs. 3.68 mg/dL; P=0.02), serum insulin levels (-2.62 vs. 4.32 µIU/ml, P=0.03) and HOMA-IR score (-0.8 vs. 1.1; P=0.03). Increased concentrations of plasma TAC (45.2 vs. -159.2 mmol/L; P<0.0001) and GSH (108.1 vs. -150.9 µmol/L; P<0.0001) were also seen in the DASH group compared with control group. We failed to find a significant difference in mean changes of serum hs-CRP levels between the two diets. Within-group comparisons revealed a significant reduction in plasma TAC and GSH levels in the control diet, while a significant rise in these biomarkers in the DASH diet. In summary, consumption of DASH diet in pregnant women with GDM had beneficial effects on FPG, serum insulin levels, HOMA-IR score, plasma TAC and total GSH levels. The effects of this dietary pattern on pregnancy outcomes need to be investigated in future studies.