The Effect of Soy Intake on Metabolic Profiles of Women With Gestational Diabetes Mellitus

Context: To our knowledge, no study has examined the effects of soy intake on metabolic status of women with gestational diabetes mellitus (GDM). Objective: This study was designed to assess the effects of soy intake on metabolic status of GDM women. Methods: A randomized clinical trial was performed among 68 women with GDM. Women were randomly assigned to receive either a control diet containing 0.8-g/kg protein (70% animal and 30% plant proteins) (n = 34) or a soy diet containing the same amount of protein with 35% animal protein, 35% soy protein, and 30% other plant proteins (n = 34) for 6 weeks. Results: Compared with soy protein consumption, the control group significantly increased fasting plasma glucose (+1.4 +/- 11.6 vs - 12.7 +/- 13.2 mg/dL, P < .001), serum insulin levels (+5.0 +/- 11.6 vs -0.9 +/- 10.0 mu IU/mL, P = .02), homeostasis model of assessment-insulin resistance (+1.2 +/- 2.7 vs -0.8 +/- 2.2, P = .002), and decreased quantitative insulin sensitivity check index (-0.007 +/- 0.02 vs +0.01 +/- 0.03, P = .004). Administration of the control diet resulted in a significant difference in serum triglycerides changes (+31.3 +/- 38.0 vs +8.9 +/- 46.1 mg/dL, P = .03) compared with soy protein. There were a significant decrease in total antioxidant capacity (-35.0 +/- 136.2 vs +81.8 +/- 188.8 mmol/L, P = .005) and glutathione (-41.3 +/- 145.7 vs +53.3 +/- 117.3 mu mol/L, P = .004) by the control diet intake compared with soy protein. The control diet group had a higher incidence of newborn hyperbilirubinemia (32.4% vs 8.8%, P = .01) and newborn hospitalization (20.6% vs 2.9%, P = .02) compared with soy protein. Conclusion: Soy protein consumption in women with GDM significantly improved the glucose homeostasis parameters, triglycerides, and biomarkers of oxidative stress, as well as reductions in the incidence of newborn hyperbilirubinemia and hospitalizations.