Vitamin K1 Improves Insulin Sensitivity
In March 2015, a study epublished in the European Journal of Clinical Nutrition found that vitamin K1 supplementation improved insulin sensitivity in prediabetic premenopausal women. According to the American Diabetes Association, 86 million Americans age 20 and older have prediabetes with elevated blood glucose but not high enough to be diagnosed with diabetes.
Researchers randomly assigned 82 prediabetic and premenopausal women to receive 1,000 μm vitamin K1 (phylloquinone) supplementation daily or a placebo for four weeks. At the beginning of the study and again after four weeks, the investigators assessed levels of carboxylated and undercarboxylated osteocalcin, a vitamin K-dependent protein secreted from osteoblasts that influences beta-cell secretion of insulin in the pancreas and adipose tissue secretion of adiponectin, resulting in an increase in insulin sensitivity. The investigators also measured two-hour post glucose tolerance test glucose and insulin as well as the insulin sensitivity index.
Vitamin K1 supplementation increased carboxylated osteocalcin and decreased undercarboxylated osteocalcin compared to placebo. Compared to placebo, vitamin K1 supplementation also significantly reduced the percentage of undercarboxylated osteocalcin, two-hour post glucose tolerance test glucose and insulin, and increased the insulin sensitivity index.
The researchers stated, “The results of this study demonstrated that vitamin K1 supplementation for four weeks did not affect insulin resistance in premenopausal and prediabetic women but had beneficial effects on glycemic status and insulin sensitivity.”
Rasekhi H, et al. Eur J Clin Nutr. 2015 Mar 18.