title: The effect of vitamin K1 supplementation on sensitivity and insulin resistance via osteocalcin in prediabetic women: a double-blind randomized controlled clinical trial.
abstract: OBJECTIVE
  A relationship between osteocalcin (OC) levels and factors associated with energy metabolism and insulin resistance has been reported recently. The aim of this study was to investigate whether modulation of ostecalcin isoforms via vitamin K1 supplementation would affect glucose metabolism or insulin sensitivity in prediabetic and premenopause women.
  
  
  METHODS
  Eighty-two prediabetic women were randomized to consume vitamin K1 supplement (n = 39) or placebo (n = 43) for 4 weeks. Participants in the vitamin K1 supplement group received one pearl softgel capsule containing 1000 μm of phylloquinone, and the placebo group received one placebo capsule daily for 4 weeks. Blood samples were collected at baseline and after the 4-week intervention period to quantify carboxylated OC (cOC), undercarboxylated OC (ucOC) and relevant variables.
  
  
  RESULTS
  Phylloquinone supplementation increased the serum levels of cOC and decreased ucOC, compared with placebo (12.53 ± 5.95 compared with 7.43 ± 4.85 ng/ml and 2.47 ± 1.91 compared with 4.79 ± 2.43 ng/ml, respectively; P < 0.001). Furthermore, intake of phylloquinone supplement led to significant decreases in %ucOC (17.97 ± 12.24 compared with 43.80 ± 19.86) and 2-h post-oral glucose tolerance test (OGTT) glucose (7.32 ± 1.50 compared with 8.62 ± 1.45 mmol/l), and 2-h post-OGTT insulin level (80.34 ± 42.24 compared with 112.43 ± 53.19 μIU/ml) and increased insulin sensitivity index (2.46 ± 0.71 compared with 1.75 ± 0.61) compared with placebo. Overall, a significant association was found between changes in %ucOC and changes in 2-h post-OGTT glucose (r = 0.308, P = 0.028).
  
  
  CONCLUSIONS
  The results of this study demonstrated that vitamin K1 supplementation for 4 weeks did not affect insulin resistance in premenopausal and prediabetic women but had beneficial effects on glycemic status and insulin sensitivity.
authors.affiliation: Nutrition and Metabolic Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: H
authors.identifier: 0000000268091100
authors.initials: H
authors.lastname: Rasekhi
authors.affiliation: Nutrition and Metabolic Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Karandish
authors.affiliation: Hyperlipidemia Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: M T
authors.initials: MT
authors.lastname: Jalali
authors.affiliation: Nutrition and Metabolic Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Mohammad-Shahi
authors.affiliation: Department of Food Hygiene, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Zarei
authors.affiliation: Department of Biostatistics and Epidemiology, School of Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Saki
authors.affiliation: Health Research Institute, Diabetes Research Center, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: H
authors.initials: H
authors.lastname: Shahbazian
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood*; D011236:Prediabetic State / Q000097:blood / Q000188:drug therapy*; D017697:Premenopause / Q000097:blood; D010837:Vitamin K 1 / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D007328:Insulin; D015675:Osteocalcin; D010837:Vitamin K 1