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

Augusta University30 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

QUADRUPLE

Enrollment

Conditions

Obesity Insulin Resistance Insulin Sensitivity Beta-Cell Dysfunction Prediabetes

Interventions

PlaceboDIETARY_SUPPLEMENT

Two placebo softgel capsules (containing no vitamin K2) every day for 8 weeks.

Low-Dose Vitamin K2 Supplement (menaquinone-7; 90-mcg/d)DIETARY_SUPPLEMENT

One 90-mcg vitamin K2 softgel capsules (containing no vitamin K2) and one placebo softgel capsule everyday for 8 weeks.

High-Dose Vitamin K2 Supplement (menaquinone-7; 180-mcg/d)DIETARY_SUPPLEMENT

Two 90-mcg vitamin K2 softgel capsules every day for 8 weeks.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

Change in insulin sensitivity

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.

Time frame: Change from baseline in insulin sensitivity at 8 weeks

Change in beta-cell function

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.

Time frame: Change from baseline in beta-cell function at 8 weeks

Secondary Outcomes

Change in prothrombin time (PT)

Time frame: Change from baseline in PT at 8 weeks

Change in activated partial thromboplastin time (aPTT)

Time frame: Change from baseline in aPTT at 8 weeks

Change in arterial stiffness (PWV)

Arterial stiffness will be assessed using carotid-femoral pulse wave velocity (PWV) by applanation tonometry.

Time frame: Change from baseline in arterial stiffness at 8 weeks

Change in endothelial function (FMD)

Endothelial function will be assessed using brachial artery flow-mediated dilation (FMD) by ultrasound.

Time frame: Change from baseline in endothelial function at 8 weeks