In a study published in the Journal of Diabetes and Metabolic Disorders, researchers at the Ahvaz Jundishapur University of Medical Sciences in Ahvaz Iran, looked at the impact of Vitamin K1 (Phylloquinone) supplementation on glucose and insulin balance. The 82 participants in the study were pre-menopausal ages 24-45 years old. They were all diagnosed with pre-diabetes based on the results of a 2-hour glucose tolerance test according to The American Diabetes Association criteria.
The women received either 1000 mcg of Vitamin K1 or a placebo once daily for 4 weeks. Blood samples were taken at baseline and after 4 weeks to measure several markers including osteocalcin, adiponectin, and leptin levels. Researchers found that compared to placebo, those taking Vitamin K showed significant decreases in 2-hour post glucose tolerance test levels. Adiponectin concentration was also increased in the Phylloquinone supplementation group. Adiponectin is a protein secreted by fat tissue which plays a role in glucose regulation and enhances insulin sensitivity.
Two markers that had no impact on Vitamin K was Leptin and Osteocalcin. Leptin is a hormone that normally inhibits appetite, stimulates thermogenesis (heat production), decreases glucose and reduces body fat. However, many people that are overweight are leptin resistant so the brain no longer reads the signals to let you know “you are full, so stop eating”.
The authors did not find any significant effect of Phylloquinone on total Osteocalcin. Osteocalcin is a protein in bone building cells (osteoblasts) that is known to increase insulin secretion in mice.
This is not the first study to identify a correlation between Vitamin K and changes in glucose metabolism and insulin sensitivity. Several epidemiological studies, which studies the patterns, causes and effects of conditions in defined populations, have shown that higher intake of Vitamin K is associated with reductions in insulin resistance and improved glucose levels.
Phylloquinone is the more common of the two biologically active forms of fat soluble Vitamin K. It is naturally found in green leafy vegetables and some types of vegetable oil. The main concern with Vitamin K is in people taking anticoagulants such as Warfarin. Vitamin K is involved in the synthesis of blood clotting factors so those on Coumadin or other anticoagulants should not take Vitamin K.
Currently the mechanism underlying the influence of Vitamin K on glycemic status and insulin homeostasis is unknown. In the meantime, the results suggest that supplementation with Phylloquinone may help improve glycemic status in premenopausal women with pre-diabetes.
References: Schepker, K. “Vitamin K Improves Glycemic Control”. Holistic Primary Care.