Vitamin K’s Role in Blood Sugar Control

Vitamin K is best known for promoting proper blood clotting and bone health.¹

 A meta-analysis of randomized controlled trials revealed that vitamin K supplementation also has favorable effects on glucose metabolism parameters and risk of developing type II diabetes.²

In observational studies, higher intake of vitamin K has been associated with a reduced risk of type II diabetes and improved markers of glucose control.^3-5

Clinical trials have shown that vitamin K supplements can improve metabolic health in adults with diabetes and prediabetes, significantly reducing elevated glucose and insulin levels.^6-8

That may help prevent the damage caused by high blood sugar in diabetics and reduce the risk of developing type II diabetes in the first place.

The Importance of Vitamin K

Vitamin K is found in green leafy vegetables, fermented foods, and some animal products, particularly organ meats. It occurs in two general forms, vitamin K1 and vitamin K2.¹

Vitamin K is required for the proper function and activation of different proteins known as vitamin K-dependent proteins.

These proteins include several clotting factors that control blood coagulation as well as osteocalcin, a protein tied to vascular and bone health.

Some of these vitamin K-dependent proteins help keep calcium in the bones, and out of blood vessels. Calcified blood vessels are one of the hallmarks of atherosclerosis and vascular dysfunction. Without adequate vitamin K, the risk of cardiovascular disease, osteoporosis, and osteopenia rises.^1,9

Other vitamin K-dependent proteins have favorable effects on metabolic function.^3,10

Link to Metabolic Health

Multiple types of research indicate that Vitamin K2 intake may lower risk of developing type II diabetes.¹¹

The vitamin's role in glucose homeostasis may be due in part to the activation of osteocalcin. In addition to its role in bone mineralization, osteocalcin stimulates healthy insulin and adiponectin expression.¹²

Studies show that people with higher intake of vitamin K tend to have better insulin sensitivity, better control of blood glucose levels, and a decreased risk of developing type II diabetes.^3,5

In an observational study embedded in a randomized controlled trial of the Mediterranean diet for prevention of cardiovascular disease, men and women without cardiovascular disease were followed for 5.5 years. Dietary information was collected annually through questionnaires.

It was found that baseline intake of vitamin K1 was lower in participants who developed diabetes during the study. It was also found that the risk of developing diabetes dropped by approximately 17% for every 100 mcg of vitamin K1 consumed per day.

Subjects who increased their dietary vitamin K1 intake over those 5.5 years had a 51% reduction in risk for developing diabetes, compared with those who did not increase vitamin K intake. The authors concluded that dietary vitamin K1 is associated with reduced risk of type II diabetes.¹³

Impressive Clinical Results

Clinical trials have confirmed that vitamin K intake (either as vitamin K1 or K2) can improve metabolic health in diabetic and nondiabetic adults.

Three randomized, controlled trials of the MK-7 form of vitamin K2 have shown clear benefits to glucose metabolism in adults with type II diabetes.^6,7,14

In all three trials, taking 90-360 mcg of MK-7 vitamin K2 daily for 3 to 6 months significantly reduced fasting blood glucose and hemoglobin A1c (HbA1c), a marker of long-term glucose control, compared to placebo.

In one of these trials, published in 2023, adults with type II diabetes who took vitamin K2 at 90 mcg per day for six months reduced fasting glucose by 13.4%, fasting insulin by 28.3%, and HbA1c by 7.4%.¹⁴ High fasting insulin is often seen in early-to-mid stage type II diabetics and can be a significant risk factor for metabolic dysfunction and diabetic complications.¹⁵

In another of these trials, a measure of insulin resistance was reduced by 55% in the group receiving 200 mcg per day of the MK-7 form of vitamin K2.⁶

Vitamin K has also been shown to lead to metabolic improvements in healthy adults and those with prediabetes.

Two placebo-controlled randomized trials showed that vitamin K can improve insulin sensitivity. One study showed that vitamin K1 benefitted older men, compared to placebo¹⁶ while the other found a similar effect in young men, using the MK-4 form of vitamin K2.¹⁷

In another randomized controlled clinical trial, prediabetic women were given 1,000 mcg of vitamin K1 or a placebo daily for four weeks. Vitamin K1 lowered blood sugar, and increased insulin sensitivity.⁸

What You Need to Know

Improve Metabolic Health

• Vitamin K has long been recognized for its importance to blood clotting and bone health. It has now been shown to also play a role in metabolic health.
• In observational studies, lower levels of vitamin K correlate with greater risk for insulin resistance and type II diabetes. Higher blood levels of vitamin K are linked to a decreased risk of diabetes.
• Clinical trials show that vitamin K intake improves metabolic health, increasing insulin sensitivity and reducing blood glucose levels, in those with diabetes and prediabetes. It also reduces the risk of developing type II diabetes.

How It Works

Vitamin K appears to improve insulin function and glucose metabolism in at least two main ways:

• Activating vitamin K-dependent proteins is involved in regulating glucose metabolism.³
• Suppressing chronic inflammation and production of pro-inflammatory compounds. These are major contributor to diminished insulin sensitivity and metabolic disease.³

Together, these actions could help reduce elevated glycemic markers and lower risk for diabetic complications.

The Difference Between Vitamin K1 and K2

Vitamin K is generally taken in two different forms.

Vitamin K1 (also known as phylloquinone) is found mostly in leafy green vegetables. It is necessary for normal, healthy blood clotting.^3,18

Vitamin K2 (menaquinone) is found in some fermented foods, dairy products, and organ meats.^3,18

The biological effects of vitamin K1 and K2 are overlapping, though each works in somewhat different ways and may be absorbed and used differently by the body.¹⁹

Optimal intake of both forms is recommended to ensure you are maximizing their potential benefits.

Summary

Low levels of vitamin K are tied to increased risk for insulin resistance, poor glycemic control, and type II diabetes.

In observational studies, higher vitamin K intake and blood levels are associated with lower risk of diabetes.

Clinical trials show that vitamin K intake improves metabolic health and lowers elevated blood glucose, in those with both type II diabetes and prediabetes. It can also help reduce the risk of developing type II diabetes.

If you have any questions on the scientific content of this article, please call a Life Extension Wellness Specialist at 1-866-864-3027.

References

1. Available at: https://lpi.oregonstate.edu/mic/vitamins/vitamin-K. Accessed June 7, 2024.
2. Qu B, Yan S, Ao Y, et al. The relationship between vitamin K and T2DM: a systematic review and meta-analysis. Food Funct. 2023 Oct 2;14(19):8951-63.
3. Ho HJ, Komai M, Shirakawa H. Beneficial Effects of Vitamin K Status on Glycemic Regulation and Diabetes Mellitus: A Mini-Review. Nutrients. 2020 Aug 18;12(8).
4. Mokgalaboni K, Nkambule BB, Ntamo Y, et al. Vitamin K: A vital micronutrient with the cardioprotective potential against diabetes-associated complications. Life Sci. 2021 Dec 1;286:120068.
5. Varsamis NA, Christou GA, Kiortsis DN. A critical review of the effects of vitamin K on glucose and lipid homeostasis: its potential role in the prevention and management of type 2 diabetes. Hormones (Athens). 2021 Sep;20(3):415-22.
6. Karamzad N, Faraji E, Adeli S, et al. Effects of MK-7 Supplementation on Glycemic Status, Anthropometric Indices and Lipid Profile in Patients with Type 2 Diabetes: A Randomized Controlled Trial. Diabetes Metab Syndr Obes. 2020;13:2239-49.
7. Rahimi Sakak F, Moslehi N, Niroomand M, Mirmiran P. Glycemic control improvement in individuals with type 2 diabetes with vitamin K(2) supplementation: a randomized controlled trial. Eur J Nutr. 2021 Aug;60(5):2495-506.
8. Rasekhi H, Karandish M, Jalali MT, et al. Phylloquinone supplementation improves glycemic status independent of the effects of adiponectin levels in premonopause women with prediabetes: a double-blind randomized controlled clinical trial. J Diabetes Metab Disord. 2015;14(1):1.
9. Available at: https://ods.od.nih.gov/factsheets/VitaminK-Consumer/. Accessed April 15, 2024.
10. O'Connor EM, Durack E. Osteocalcin: The extra-skeletal role of a vitamin K-dependent protein in glucose metabolism. Journal of Nutrition & Intermediary Metabolism. 2017 2017/03/01/;7:8-13.
11. Jakubowski P. Current View on Vitamin K2 Role in Diseases Based on Clinical Trials. Farmacia. 2019;67(4):551-6.
12. Kanazawa I. Osteocalcin as a hormone regulating glucose metabolism. World J Diabetes. 2015 Dec 25;6(18):1345-54.
13. Ibarrola-Jurado N, Salas-Salvado J, Martinez-Gonzalez MA, Bullo M. Dietary phylloquinone intake and risk of type 2 diabetes in elderly subjects at high risk of cardiovascular disease. Am J Clin Nutr. 2012 Nov;96(5):1113-8.
14. Zhang Y, Liu L, Wei C, et al. Vitamin K2 supplementation improves impaired glycemic homeostasis and insulin sensitivity for type 2 diabetes through gut microbiome and fecal metabolites. BMC Med. 2023 May 5;21(1):174.
15. Vaidya RA, Desai S, Moitra P, et al. Hyperinsulinemia: an early biomarker of metabolic dysfunction. Front Clin Diabetes Healthc. 2023;4:1159664.
16. Yoshida M, Jacques PF, Meigs JB, et al. Effect of vitamin K supplementation on insulin resistance in older men and women. Diabetes Care. 2008 Nov;31(11):2092-6.
17. Choi HJ, Yu J, Choi H, et al. Vitamin K2 supplementation improves insulin sensitivity via osteocalcin metabolism: a placebo-controlled trial. Diabetes Care. 2011 Sep;34(9):e147.
18. Fusaro M, Gallieni M, Porta C, et al. Vitamin K effects in human health: new insights beyond bone and cardiovascular health. J Nephrol. 2020 Apr;33(2):239-49.
19. Hariri E, Kassis N, Iskandar JP, et al. Vitamin K(2)-a neglected player in cardiovascular health: a narrative review. Open Heart. 2021 Nov;8(2).