This study was performed to evaluate the effects of selenium supplementation on gene expression related to insulin and lipid metabolism, and pregnancy outcomes in patients with gestational diabetes mellitus (GDM). The current randomized, double-blind, placebo-controlled clinical trial was conducted in 36 patients with GDM. Participants were randomly divided into two groups to intake either 200 μg/day selenium supplements as selenium yeast or placebo (n = 18 each group) for 6 weeks. Selenium supplementation upregulated peroxisome proliferator-activated receptor gamma (P = 0.03) and glucose transporter 1 (GLUT-1) (P = 0.01) in lymphocytes of subjects with GDM compared with the placebo. Selenium supplementation did not affect gene expression of low-density lipoprotein receptor (LDLR) and lipoprotein(a) [Lp(a)]. Supplementation with selenium had a significant decrease in incidence of newborns' hyperbilirubinemia (5.6% vs. 33.3%, P = 0.03) and newborns' hospitalization (5.6% vs. 33.3%, P = 0.03) compared with the placebo. Overall, we found that selenium supplementation for 6 weeks among patients with GDM significantly increased PPAR-γ and GLUT-1 expression, but did not affect gene expression of LDLR and LP(a). It also reduced incidence of newborns' hyperbilirubinemia and newborns' hospitalization. Clinical trial registration number: http://www.irct.ir: IRCT20170513033941N35.
Keywords: Gene expression; Gestational diabetes mellitus; Pregnancy outcomes; Selenium supplementation.