BackgroundVitamin D deficiency in women diagnosed with polycystic ovary syndrome (PCOS) remarkably decreases the chance of pregnancy, which might be related to its impact on metabolic abnormalities in these patients. It is hypothesized that vitamin D supplementation influences metabolic profile of these patients and indirectly might affect fertility and the outcomes. Therefore, this study was conducted to determine the effects of vitamin D supplementation on the levels of anti-Müllerian hormone (AMH), metabolic profiles, and gene expression of insulin and lipid metabolism in infertile women with PCOS who were candidate for in vitro fertilization (IVF).MethodsThis study was a randomized, double-blinded, placebo-controlled trial conducted among 40 infertile women, aged 18–40 years, diagnosed with PCOS and was candidate for IVF. Participants were randomly assigned into two intervention groups for receiving either 50,000 IU vitamin D or placebo (n = 20 each group) every other week for 8 weeks. Gene expression for insulin and lipid metabolism was conducted using peripheral blood mononuclear cells (PBMCs) of women with PCOS, via RT-PCR method.ResultsVitamin D supplementation led to a significant reduction in serum AMH (− 0.7 ± 1.2 vs. − 0.1 ± 0.5 ng/mL, P = 0.02), insulin levels (− 1.4 ± 1.6 vs. -0.3 ± 0.9 μIU/mL, P = 0.007), homeostatic model of assessment for insulin resistance (− 0.3 ± 0.3 vs. -0.1 ± 0.2, P = 0.008), and a significant increase in quantitative insulin sensitivity check index (+ 0.009 ± 0.01 vs. + 0.001 ± 0.004, P = 0.04), compared with the placebo. Moreover, following vitamin D supplementation there was a significant decrease in serum total- (− 5.1 ± 12.6 vs. + 2.9 ± 10.9 mg/dL, P = 0.03) and LDL-cholesterol levels (− 4.5 ± 10.3 vs. + 2.5 ± 10.6 mg/dL, P = 0.04) compared with the placebo.ConclusionOverall, the findings of this trial supported that 50,000 IU vitamin D supplementation every other week for 8 weeks had beneficial effects on insulin metabolism, and lipid profile of infertile women with PCOS who are candidate for IVF. These benefits might not be evident upon having sufficient vitamin D levels.Trial registrationThis study was retrospectively registered in the Iranian website (www.irct.ir) for clinical trials registration (http://www.irct.ir: IRCT20170513033941N27).

The current systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to summarize the effect of vitamin D supplementation on biomarkers of inflammation and oxidative stress among women with polycystic ovary syndrome (PCOS). Cochrane library, Embase, PubMed, and Web of Science database were searched to identify related randomized-controlled articles (RCTs) published up to November 2017. Two researchers assessed study eligibility, extracted data, and evaluated risk of bias of included RCTs, independently. To check heterogeneity Q-test and I statistics were used. Data were pooled by using the random-effect model and standardized mean difference (SMD) was considered as summary effect size. Seven RCTs were included into our meta-analysis. The findings showed that vitamin D supplementation in women with PCOS significantly decreased high-sensitivity C-reactive protein (hs-CRP) (SMD -1.03; 95% CI, -1.58, -0.49; p <0.001) and malondialdehyde (MDA) (SMD -1.64, 95% CI -2.26 to -1.02, p <0.001), and significantly increased total antioxidant capacity (TAC) levels (SMD 0.86, 95% CI 0.08 to 1.64, p=0.03). Vitamin D supplementation had no significant effect on nitric oxide (NO) (SMD 0.11, 95% CI -0.44 to 0.66, p=0.69) and total glutathione (GSH) levels (SMD 0.54, 95% CI -0.20 to 1.28, p=0.15). Overall, the current meta-analysis demonstrated that vitamin D supplementation to women with PCOS resulted in an improvement in hs-CRP, MDA and TAC, but did not affect NO and GSH levels.

Overall, zinc and vitamin E cosupplementation for 6 weeks in women with GDM significantly improved insulin metabolism, lipid profile, and the gene expression levels of PPAR-γ and LDLR.