A randomized controlled clinical trial investigating the effect of DASH diet on insulin resistance, inflammation, and oxidative stress in gestational diabetes.

OBJECTIVE: To our knowledge, no reports are available indicating the effects of the dietary approaches to stop hypertension (DASH) eating plan on insulin resistance, inflammation, and oxidative stress among pregnant women with gestational diabetes mellitus (GDM). This study was designed to investigate the effects of the DASH diet on insulin resistance, serum high-sensitivity C-reactive protein (hs-CRP) and biomarkers of oxidative stress among pregnant women with GDM.

METHODS: This randomized controlled clinical trial was performed with 32 pregnant women diagnosed with GDM at 24 to 28 wk gestation. Participants were randomly assigned to consume either the control (n = 16) or DASH diet (n = 16) for 4 wk. The DASH diet was rich in fruits, vegetables, whole grains, and low-fat dairy products and was low in saturated fats, total fats, cholesterol, refined grains, and sweets, with a total of 2400 mg/d of sodium. The control diet contained 40% to 55% of its energy as carbohydrates, 10% to 20% as proteins, and 25% to 30% as total fats. Fasting blood samples were taken at baseline and after 4 wk of intervention to measure fasting plasma glucose (FPG), serum insulin, and hs-CRP, homeostasis model of assessment-insulin resistance (HOMA-IR), plasma total antioxidant capacity (TAC), and total glutathione levels (GSH).

RESULTS: Consumption of the DASH diet compared with the control diet resulted in decreased FPG (-7.62 versus 3.68 mg/dL; P = 0.02), serum insulin levels (-2.62 versus 4.32 μIU/mL, P = 0.03), and HOMA-IR score (-0.8 versus 1.1; P = 0.03). Increased concentrations of plasma TAC (45.2 versus -159.2 mmol/L; P < 0.0001) and GSH (108.1 versus -150.9 μmol/L; P < 0.0001) also were 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 significant reductions in plasma TAC and GSH levels in the control diet, while a significant increase in these biomarkers in the DASH diet.

CONCLUSION: Consumption of the 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.