Vitamin K and Glucose Metabolism in Adults at Risk for Diabetes (Vita-K 'n' Adults Study)

Not Applicable

• Conditions: Obesity; Insulin Sensitivity; Prediabetes; Insulin Resistance; Beta-Cell Dysfunction
• Interventions: Dietary Supplement: Low-Dose Vitamin K2 Supplement (menaquinone-7; 90-mcg/d); Dietary Supplement: High-Dose Vitamin K2 Supplement (menaquinone-7; 180-mcg/d); Dietary Supplement: Placebo

• Registration Number: NCT02366481
• Lead Sponsor: Augusta University

Brief Summary

Given that glutamate carboxylation or decarboxylation is key to the metabolic role of osteocalcin (at least in mouse models) and that carboxylation is vitamin K dependent, it is critical to isolate the effect of vitamin K manipulation on carboxylation of osteocalcin and its subsequent effect on glucose metabolism in clinical trials. The purpose of this randomized, double-blind, placebo-controlled clinical trial in adults is to determine whether eight weeks of daily supplementation with vitamin K2 (menaquinone-7) can improve markers in blood associated with diabetes risk.

Detailed Description

Not available

Study Timeline

• Study Start: 2015-02
• Study First Submitted: 2015-02-12
• Study First Submitted QC: 2015-02-12
• Study First Posted: 2015-02-19
• Status Verified: 2019-11
• Last Update Submitted: 2019-11-18
• Last Update Posted: 2019-11-20
• Primary Completion: 2020-06-01
• Study Completion: 2020-06-30

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

1. Healthy adults between 18 and 65 years old
2. Subject understands the study protocol and agrees to comply with it
3. Informed Consent Form signed by the subject

Exclusion Criteria

1. Subjects using vitamin supplements containing vitamin k
2. Subjects with (a history of) metabolic or gastrointestinal diseases including hepatic disorders
3. Subjects presenting chronic degenerative and/or inflammatory diseases
4. Subjects receiving systemic treatment or topical treatment likely to interfere with evaluation of the study parameters (salicylates, antibiotics)
5. Subjects receiving corticosteroid treatment
6. Subjects using oral anticoagulants
7. Subjects with a history of soy allergy
8. Subjects who have participated in a clinical study more recently than one month before the current study

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Low-Dose Vitamin K2 (90-mcg/d)	Low-Dose Vitamin K2 Supplement (menaquinone-7; 90-mcg/d)	The low-dose vitamin K group will take one 90-mcg vitamin K2 (menaquinone-7) softgel capsule and one placebo softgel capsule every day for 8 weeks.
High-Dose Vitamin K2 (180-mcg/d)	High-Dose Vitamin K2 Supplement (menaquinone-7; 180-mcg/d)	The high-dose vitamin K group will take two 90-mcg vitamin K2 (menaquinone-7) softgel capsules every day for 8 weeks.
Placebo-Control	Placebo	The placebo-control group will take two placebo softgel capsules every day for 8 weeks.

Primary Outcome Measures

Name	Time	Method
Change in insulin sensitivity	Change from baseline in insulin sensitivity at 8 weeks	Insulin sensitivity will be calculated from plasma insulin and glucose concentrations measured during a 2-hour oral glucose tolerance test by using the oral glucose minimal model.
Change in beta-cell function	Change from baseline in beta-cell function at 8 weeks	Beta-cell function, as assessed by dynamic beta-cell responsitivity, will be calculated from plasma glucose and C-peptide concentrations measured during a 2-hour oral glucose tolerance test by using the oral C-peptide minimal model.

Secondary Outcome Measures

Name	Time	Method
Change in arterial stiffness (PWV)	Change from baseline in arterial stiffness at 8 weeks	Arterial stiffness will be assessed using carotid-femoral pulse wave velocity (PWV) by applanation tonometry.
Change in prothrombin time (PT)	Change from baseline in PT at 8 weeks
Change in activated partial thromboplastin time (aPTT)	Change from baseline in aPTT at 8 weeks
Change in endothelial function (FMD)	Change from baseline in endothelial function at 8 weeks	Endothelial function will be assessed using brachial artery flow-mediated dilation (FMD) by ultrasound.

Trial Locations

Locations (1)

Medical College of Georgia; Augusta University; 🇺🇸 Augusta, Georgia, United States