title: The Effects of Vitamin D Supplementation on Glucose Control and Insulin Resistance in Patients with Diabetes Type 2: A Randomized Clinical Trial Study.
abstract: BACKGROUND
  Vitamin D deficiency is prevalent in diabetes type 2 and this vitamin may be related to insulin action. This randomized controlled trial study was done to evaluate the effect of vitamin D supplementation on glucose control and insulin resistance in patients with diabetes type 2.
  
  
  METHODS
  Participants of this randomized clinical trial study consisted of 28 patients with type 2 diabetes who received 100 microgram (4000 IU) vitamin D and 30 diabetic patients who received placebo for 2 months between September 2012 and February 2013. The effect of vitamin D on glucose control was assessed by measuring HbA1c and insulin resistance as HOMA-IR at the baseline and the end of the intervention.
  
  
  RESULTS
  The results showed a significant decrease in HbA1c (from 7.29 ± 0.22 % to 6.76 ± 0.18 %, P<0.001) and insulin concentration (from 8.24 ± 0.97 μIU/mL to 6.55 ± 0.28 μIU/mL, P=0.048), but a non-significant decrease in HOMA-IR in vitamin D group. Also, HDL-C level increased significantly in both of vitamin D (P=0.046) and placebo groups (P=0.028).
  
  
  CONCLUSIONS
  It seems that vitamin D supplementation has beneficial effects on glucose homeostasis and can increases insulin sensitivity in diabetic 2 patients.
authors.affiliation: Dept. of Cellular and Molecular Nutrition, School of Nutritional Sciences And Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Esmaeil
authors.initials: E
authors.lastname: Yousefi Rad
authors.affiliation: Dept. of Cellular and Molecular Nutrition, School of Nutritional Sciences And Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Djalali
authors.affiliation: Dept. of Cellular and Molecular Nutrition, School of Nutritional Sciences And Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Fariba
authors.initials: F
authors.lastname: Koohdani
authors.affiliation: Dept. of Cellular and Molecular Nutrition, School of Nutritional Sciences And Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Saboor-Yaraghi
authors.affiliation: Dept. of Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Eshraghian
authors.affiliation: Dept. of Cellular and Molecular Nutrition, School of Nutritional Sciences And Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Hassan
authors.initials: MH
authors.lastname: Javanbakht
authors.affiliation: Dept. of Cellular and Molecular Nutrition, School of Nutritional Sciences And Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Somayeh
authors.initials: S
authors.lastname: Saboori
authors.affiliation: Dept. of Cellular and Molecular Nutrition, School of Nutritional Sciences And Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Zarei
authors.affiliation: Dept. of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Hosseinzadeh-Attar
keywords: Diabetes type 2; HbA1c; Insulin resistance; Vitamin D