Vitamin K may improve blood sugar control, insulin sensitivity, and type 2 diabetes

An increasing number of people are struggling with excess weight and blood sugar disorders linked to insulin resistance and prediabetes. It is estimated that 500 million people worldwide currently have type 2 diabetes, a condition associated with reduced quality of life, high blood pressure, cardiovascular disease, and premature death. Diet and lifestyle play a major role, and according to a review article published in Nutrients, vitamin K supplementation may improve blood sugar regulation through several important mechanisms.

Type 2 diabetes is a chronic metabolic disorder that initially develops as insulin resistance - a condition in which the body's cells become less responsive to insulin and less able to absorb glucose from the bloodstream. As a result, both blood sugar and insulin levels remain chronically elevated, contributing to increased hunger, abdominal weight gain, and high blood pressure. At the same time, the liver begins producing excessive amounts of cholesterol and triglycerides. Overall, the condition is characterized by chronic inflammation and oxidative stress, in which free radicals damage cells and blood vessels.
These metabolic disturbances increase the risk of a wide range of complications, including cardiovascular disease, erectile dysfunction, polycystic ovary syndrome (PCOS), diabetic retinopathy, diabetic neuropathy, amputation, and premature death.
It is estimated that 500 million people worldwide currently have type 2 diabetes, and that number is expected to rise to 700 million by 2045.
The modern diet, characterized by large amounts of ultra-processed foods, refined carbohydrates, and omega-6-rich vegetable oils, is widely recognized as a major contributing factor. Researchers have also observed that poor blood sugar control in people with type 2 diabetes is often associated with vitamin K deficiency. Since preclinical studies have already demonstrated promising effects of vitamin K on glucose regulation, the authors of the new review sought to examine the evidence from human studies more closely.

Vitamin K supplementation improves markers of glucose metabolism

The purpose of the review was to evaluate the effects of vitamin K supplementation on key metabolic markers, including fasting blood glucose (FBG), fasting insulin (FI), long-term blood sugar control (HbA1c), insulin resistance (HOMA-IR), and the function of the insulin-producing beta cells in the pancreas.
By trawling databases such as PubMed and Scopus, the researchers identified eight randomized controlled trials (RCTs) involving patients with prediabetes or type 2 diabetes who received different forms of vitamin K or a placebo.
Overall, the analysis showed that vitamin K supplementation can significantly improve blood sugar regulation through the following mechanisms:

• Lower fasting blood glucose (FBG)
• Lower HbA1c levels
• Reduced insulin resistance (HOMA-IR)
• Improved insulin sensitivity and pancreatic beta-cell function

The form, dosage, and duration of vitamin K supplementation matter

The authors emphasize that vitamin K exists primarily in two forms.
Vitamin K1 (phylloquinone) is best known for its role in normal blood clotting. It is found mainly in dark green vegetables such as parsley, spinach, kale, and green beans. Intestinal bacteria can also convert vitamin K1 into vitamin K2 under favorable conditions.
Vitamin K2 (menaquinone) is found primarily in fermented foods, egg yolks, butter, aged cheeses, and fatty cuts of meat from grass-fed animals.
Vitamin K2 is required for activating proteins that help remove calcium from the bloodstream and direct it into the bones. In this way, vitamin K2 supports cardiovascular and bone health by helping to prevent arterial calcification and osteoporosis.
The review also confirmed an important role for vitamin K in blood sugar regulation. Further analyses of vitamin K form, dosage, and patient subgroups revealed several noteworthy findings:

• Low daily doses of vitamin K (90–200 mcg) significantly improved blood sugar control and insulin sensitivity
• Higher daily doses (1,000 mcg) improved the function of insulin-producing beta cells in people with prediabetes, but not in those with established diabetes
• Overweight participants experienced greater improvements in HbA1c compared with normal-weight participants
• The benefits of vitamin K supplementation were particularly pronounced in individuals over 50 years of age and in studies lasting longer than 12 weeks
• Vitamin K2 supplementation produced greater improvements than vitamin K1 in insulin sensitivity, HbA1c levels, and the reduction of type 2 diabetes risk

The authors therefore conclude that vitamin K supplementation - vitamin K2 - may improve insulin sensitivity, blood sugar control, and other markers associated with prediabetes and type 2 diabetes.
Although vitamin K supplements cannot replace established diabetes treatments, the findings suggest that they may serve as a valuable adjunct by supporting glucose regulation through multiple pathways.

Dietary strategies for preventing and managing diabetes

Because type 2 diabetes is largely influenced by lifestyle factors, it may be beneficial to increase the intake of vitamin K-rich foods while also focusing on adequate protein, healthy fats, and bitter-tasting vegetables, all of which can contribute to better blood sugar regulation.
In the following article, you can learn more about the role that various vitamins and minerals play in blood sugar control and diabetes management.

• The role of vitamins and minerals in the treatment of diabetes

Reference:

Syeda Ruwaida Ahmed et al. The Differential Effects of Vitamin K Across Glycaemic Outcomes in Prediabetes and Type 2 Diabetes Mellitus. Nutrients 2026

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