The association between vitamin K2 intake and glucose homeostasis in individuals with and without chronic kidney disease

Abstract

Background: Type 2 diabetes mellitus (T2DM) is the most common metabolic disorder worldwide. Subclinical micronutrient deficiencies have been found to contribute to glucose intolerance and insulin resistance. Vitamin K₂, in particular, possesses extrahepatic activities that may influence glucose metabolism. Individuals with chronic kidney disease (CKD) have poorer vitamin K status as well as impaired insulin sensitivity and glucose tolerance. However, whether or not the poorer metabolic outcome correlates with intakes of vitamin K₂ is unclear.

Objective: The objective was to investigate whether the intake of vitamin K₂ is associated with glucose tolerance and key factors determining glucose tolerance.

Design: A cross-sectional investigation was undertaken using data from the Study of Glucose and Insulin in Renal Disease (SUGAR) study that involved individuals with (n=53) and without CKD (n=39). Three-day dietary records were used to estimate intakes of vitamin K₂, using values of vitamin K₂ for foods in nutrient databases and relevant publications. Intravenous-glucose-tolerance tests (IVGTT), oral glucose-tolerance test (OGTT) and hyperinsulinemic-euglycemic clamps were performed to assess glucose tolerance, β-cell function and insulin sensitivity.

Results: In multivariate analyses adjusted for age, sex, BMI, race/ethnicity, eGFR and vitamin D status, higher vitamin K₂ intake was associated with better glucose tolerance (P = 0.047). Higher vitamin K₂ intake was also associated with insulin sensitivity (P = 0.017) in a crude model, but this association was attenuated and no longer significant after adjusting for classical risk factors. Vitamin K₂ intake was not associated with β-cell function.

Conclusion: Higher vitamin K₂ intake was associated with better glucose tolerance.