EFFECT OF VITAMIN K SUPPLEMENTATION ON GLYCEMIC CONTROL: A SYSTEMATIC REVIEW AND META-ANALYSIS OF CLINICAL TRIALS

Background and Aim: Type 2 diabetes mellitus (T2DM) is one of the most important public health issues. Vitamin K supplementation might have favorable effect on risk factors of T2DM. The aim of this study was to perform a systematic review and meta-analysis of interventional studies to examine the effect of vitamin K supplementation on glycemic indices.Methods: A systematic search was performed in electronic databases including PubMed, ScienceDirect, ProQuest, Institute of Scientific Information Web of Science, and Google scholar up to July 2017. We used a random effects model to estimate pooled effect size of fasting blood sugar (FBS), 2-hour oral glucose tolerance test (2-h OGTT), fasting insulin (FINS), and homeostasis model assessment-estimated insulin resistance (HOMA-IR).Results: Five clinical trials (533 participants) fulfilled the eligibility criteria of the present meta-analysis. Overall, meta-analysis could not show any beneficial effect of vitamin K supplementation on FBS (-0.91 mg/dl, 95%CI: -2.57, 0.76, P=0.28), FINS (-0.35 µIU/ml, 95%CI: -1.70, 1.00, P=0.61), HOMA-IR (-0.06, 95%CI: -0.32, -0.19, P=0.63) and 2-h OGTT (-4.00 mg/dl, 95%CI: -20.00, 11.99, P=0.62). Sensitivity analysis showed that overall estimates were not affected by elimination of any study.We did not observe any evidence regarding publication bias.Conclusion: In conclusion, vitamin K supplementation had no significant effect on glycemic control in healthy subjects. However, further studies should be performed on diabetic and pre-diabetic patients to determine the effect of vitamin K supplementation on impaired glycemic control.

کلیدواژه ها:

Vitamin K ، Fasting blood sugar ، Serum insulin ، glycemic control ، meta-analysis