Horm Metab Res 2018; 50(03): 227-235
DOI: 10.1055/s-0044-100616
Endocrine Care
© Georg Thieme Verlag KG Stuttgart · New York

Effect of Vitamin K Supplementation on Glycemic Control: A Systematic Review and Meta-Analysis of Clinical Trials

Authors

  • Farnaz Shahdadian

    1   Student Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran
  • Hamed Mohammadi

    1   Student Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran
  • Mohammad Hossein Rouhani

    2   Department of Community Nutrition, School of Nutrition and Food Science, Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
Further Information

Publication History

received 01 August 2017

accepted 04 January 2018

Publication Date:
09 March 2018 (online)

Abstract

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. A systematic search was performed in electronic databases including PubMed, Science Direct, 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-h oral glucose tolerance test (2-h OGTT), fasting insulin (FINS), and homeostasis model assessment-estimated insulin resistance (HOMA-IR). 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. 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.