The effects of vitamin D supplementation on hs-CRP, metabolic profile and oxidative stress in pregnant women: a double blind randomized controlled clinical trial

Increased pro-inflammatory factors, metabolic profile and biomarkers of oxidative stress during pregnancy have been associated with development of several complications. To our knowledge, no reports are available indicating the effects of vitamin D supplementation on serum hs-CRP, metabolic profile and bio markers of oxidative stress among pregnant women. This study was done to determine the effects of vitamin D supplementation on serum hs-CRP, metabolic profile and biomarkers of oxidative stress among pregnant women. This randomized double-blind controlled clinical trial was conducted among 48 pregnant women, primigravida, aged 18-40 year old who were carrying singleton pregnancy at 25 weeks’ gestation. Participants were randomly assigned to receive either 400 IU/d vitamin D supplements (n=24) or placebo (n=24) for 9 weeks. Fasting blood samples were taken at baseline and after 9 weeks’ intervention to measure hs-CRP, metabolic profile and biomarkers of oxidative stress including plasma total antioxidant capacity (TAC) and total glutathione (GSH). Vitamin D supplementation resulted in increased levels of vitamin D (+3.62 vs.-1.2 ng/mL,Pgroup=0.003) and calcium(+0.2 vs.-0.12mg/dL, Pgroup=0.01). Individuals who took vitamin D supplements had a significant decrease in their serum hs-CRP levels (-1411.7 vs. 1503ng/mL,Pgroup=0.01) and a significant rise in their plasma serum TAC concentrations 151.94 vs. -19.69mmol/l,Pgroup=0.002) compared with those who took placebo. A borderline significant effects of vitamin D supplementation on reducing serum triglyceride levels (Pgroup=0.06) and diastolic blood pressure (Pgroup=0.07) was also observed. We failed to find a significant effect of vitamin D supplementation on FPG, serum insulin levels, systolic blood pressure, other lipid profiles and plasma GSH. In conclusion, vitamin D supplementation for 9 weeks among pregnant women resulted in reduced serum hs-CRP levels and increased plasma TAC, serum vitamin D and calcium concentrations. Furthermore, vitamin D supplements led to a borderline significant effect on DBP and serum triglycerides; however, it could not affect other serum metabolic profiles.