Effects of vitamin D supplementation on insulin resistance and lipid metabolic profiles in women with gestational diabetes mellitus: A randomized controlled trial.

Gestational diabetes mellitus (GDM) commonly presents as insulin resistance and altered lipid metabolism, with evidence linking vitamin D deficiency to its pathogenesis. In this randomized, double-blind, placebo-controlled trial, 120 pregnant women diagnosed with GDM were assigned to receive either vitamin D3 supplements (2000 IU/day) or a placebo for 3 months. Serum vitamin D status, glycemic control parameters, and lipid profiles were evaluated pre- and post-intervention, adjusting for dietary and exercise confounders. After the 3-month intervention, serum 25-hydroxyvitamin D levels in the vitamin D group were significantly higher than those in the placebo group. Vitamin D supplementation effectively reduced fasting plasma glucose, fasting insulin, and HOMA-IR scores. Simultaneously, it significantly decreased triglycerides and LDL-C levels while increasing HDL-C. Total cholesterol levels showed no statistically significant difference between the two groups. Supplementation with 2000 IU vitamin D per day for 3 months yields significant improvements in glucose homeostasis and lipid metabolism in the GDM population. Vitamin D holds promise as an effective auxiliary treatment to enhance maternal metabolic health.