vitamin-k-semiquinone-radical and Prediabetic-State

Diabetes mellitus and pre-diabetes are prevalent endocrine disorders associated with substantial morbidity and premature mortality. Vitamin K is known to have several beneficial effects on complications of diabetes and pre-diabetes. However, systematic consolidation of evidence is required to quantify these effects in order to inform clinical practice and research. A systematic search in PubMed, Scopus, Embase, ProQuest, and Google Scholar databases was undertaken from database inception up to October 2018 to evaluate functional roles of different forms of vitamin K on diabetes and pre-diabetes. From 3,734 identified records, nine articles met the inclusion criteria and were evaluated. Vitamin K supplementation was found to be associated with significant reductions in blood glucose (six studies), increased fasting serum insulin (four studies), reduced hemoglobin A1c (three studies), reduced homeostatic model assessment-insulin resistance index (HOMA-IR) (two studies), and increased ß-cell function (two studies) in diabetic animal studies. Following 2-hour oral glucose tolerance test, vitamin K supplementation was observed to be effective in reducing blood glucose and insulin levels in the pre-diabetic population. However, no evidence of effect was observed for fasting blood sugar, insulin, HOMA-IR, and homeostatic model assessment-β-cell function index (two studies). A statistically significant effect was also noted with vitamin K in improving dyslipidemia (three studies) as well as oxidative stress and inflammatory markers (five studies) in diabetic animals. In conclusion, clinical trials and animal studies confirm that vitamin K supplementation may improve both clinical features and complications of diabetes and pre-diabetes. However, quantification of clinical efficacy in the pre-diabetic population and among individuals with comorbidities requires further investigation.

Topics: Animals; Diabetes Complications; Dietary Supplements; Humans; Prediabetic State; Vitamin K; Vitamins

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.

Topics: Blood Glucose; Diabetes Mellitus, Type 2; Dietary Supplements; Humans; Prediabetic State; Vitamin K