The Effects of Vitamin D and Probiotic co-Supplementation on Glucose Homeostasis, Inflammation, Oxidative Stress and Pregnancy Outcomes in Gestational Diabetes: A Randomized, Double-Blind, Placebo-Controlled Trial

Objective: This study was designed to assess the effects of combined vitamin D and probiotic supplementation on metabolic status, and pregnancy outcomes among pregnant women with gestational diabetes (GDM).Methods: This randomized, double-blind, placebo-controlled clinical trial was performed among 87 women with GDM. Patients were randomly assigned to receive either vitamin D (50,000 IU/every 2 weeks) plus probiotic (8×109 CFU/day) (n=30), probiotic (8×109 CFU/day) (n=29) or placebo (n=28) for 6 weeks. Fasting blood samples were taken at baseline and after the 6-week intervention to quantify related variables. Results: Subjects who received vitamin D plus probiotic supplements had significantly lower fasting plasma glucose (-12.3±4.7 vs. -10.1±7.2 and -1.1±6.4 mg/dL, respectively, P<0.001), serum insulin levels (-2.0±2.1 vs. -1.4±2.9 and -0.2±1.4 μIU/mL, respectively, P=0.008), homeostasis model of assessment-insulin resistance (-0.8±0.5 vs. -0.6±0.9 and -0.1±0.5, respectively, P<0.001), and higher quantitative insulin sensitivity check index (+0.02±0.02 vs. +0.01±0.02 and +0.001±0.007, respectively, P=0.006) compared with only probiotic and placebo. In addition, vitamin D plus probiotic supplementation resulted in a significant reduction in serum triglycerides (-24.9±32.9 vs. -7.6±28.1 and +14.7±20.2 mg/dL, respectively, P<0.001), VLDL-cholesterol levels (-4.9±6.6 vs. -1.5±5.6 and +2.9±4.0 mg/dL, respectively, P<0.001) and total-/HDL-cholesterol (-0.4±0.7 vs. -0.04±0.5 and +0.1±0.4, respectively, P=0.003), and a significant increase in HDL-cholesterol levels (+3.0±6.1 vs. +0.3±6.8 and -1.2±5.3 mg/dL, respectively, P=0.03) compared with only probiotic and placebo. Additionally, vitamin D plus probiotic intake resulted in a significant reduction in serum high sensitivity C-reactive protein (-1.8±1.5 vs. -1.0±1.3 and +0.4±1.9 mg/L, respectively, P<0.001) and plasma malondialdehyde (-0.3±0.7 vs. -0.1±0.4 and +0.2±0.8 μmol/L, respectively, P=0.02), and a significant increase in total antioxidant capacity levels (+62.5±87.8 vs. +15.9±50.7 and -18.3±124.5 mmol/L, respectively, P=0.005) compared with only probiotic and placebo. Conclusions: In conclusion, vitamin D and probiotic co-supplementation in pregnant women with GDM had beneficial effects on metabolic status. This trial was registered at www.irct.ir as IRCT201706075623N119.

Keywords:

Supplementation , gestational diabetes , pregnant women