By Chris D. Meletis, N.D.

Vitamin D3 plus vitamin K2 is the perfect pairing.

For bone and heart health, the benefits of vitamin D are magnified if you take it with vitamin K2. Vitamin D3 helps your body use calcium while vitamin K2 escorts the calcium into your bones where it’s needed, rather than allowing calcium deposits to build up in the arteries. This keeps the arteries flexible and healthy.

What does the science say about the benefit of vitamin D3 and K2? Let’s take a look.

Vitamin D3 and K2: Keeping Bones Strong

Vitamin K2’s ability to transport calcium into the bones keeps them strong and healthy. For example, in one study vitamin D3 and K2 taken together with calcium promoted greater bone formation and bone mineral density (BMD) compared to vitamin D3 and calcium alone.¹ In another study, researchers divided 92 postmenopausal women ages 55 to 81 into four groups who were given the following:²

• Vitamin D3 alone
• Vitamin K2 alone
• Vitamin D3 plus K2
• Calcium

Researchers measured BMD of the lumbar spine in each of the groups. In the group given only calcium, BMD significantly decreased. Compared to the calcium only, vitamin D3 only, and vitamin K2 only groups, BMD significantly increased in the group given both vitamin D and vitamin K.  

In a third study, scientists investigated the effect of vitamins D3 and K2 on bone loss caused by estrogen deficiency.³ The study included 110 women divided into four groups. Each group was given the following:

• Only an estrogen-lowering drug
• The estrogen-lowering drug plus vitamin K2
• The estrogen-lowering drug plus vitamin D3
• The estrogen-lowering drug plus vitamins D3 and K2

In the study, authors measured the BMD of the lumbar spine and bone formation before and after six months of treatment. Although the group receiving both vitamin D3 and vitamin K2 still experienced bone loss, the amount of bone loss was less than in the other groups.

Cell culture research has shown that vitamin K2 supports the health of bone-building cells known as osteoblasts and that vitamin D3 enhances this support.⁴ 

Animal research also backs up the evidence that vitamins D and K need to work together to be most effective in bone health. Researchers gave rats without ovaries vitamin K to block bone loss, but bone loss was only blocked in rats that were fed a diet containing vitamin D or that were given vitamin D supplements.^5,6 According to one group of researchers, “These findings suggest that combined treatment with vitamins D and K is more effective than vitamin K alone particularly in the early phase of estrogen deficiency after menopause.”⁷

Cardio Benefits of Vitamin D3 and K2

Combining vitamin D3 with K2 may keep the cardiovascular system healthy, due to vitamin K2’s ability to keep calcium out of the arteries and in the bones. In a couple different groups of patients, including pediatric patients undergoing hemodialysis and postmenopausal women,^8,9 three years of supplementation with vitamins D and K led to healthy and flexible arteries.

Other research found a relationship between optimal vitamin D and K levels and healthy blood pressure levels already in the normal range.¹⁰ In another study, a combination of vitamin K2 and vitamin D3 led to reduced carotid intima-media thickness in chronic kidney disease patients not on dialysis.¹¹ Higher carotid intima-media thickness is associated with plaque build-up.

Another way in which vitamins D and K may promote cardiovascular health is by supporting healthy glucose and insulin metabolism. In a group of vitamin D deficient women with polycystic ovary syndrome, a combination of calcium, vitamin D, and K for eight weeks improved the way the body handled insulin and metabolized fats compared to a placebo.¹²

It should be noted that many of these studies on vitamin D and K used only low amounts of vitamin D—around 400 IU—when clinically I have noted that much higher levels of vitamin D3 in the range of at least 2000 IU or more are needed to bring vitamin D levels up to a meaningful range.

Tap Into the Health Benefits of Vitamin D and K2

Trace Minerals Research combines these two critical nutrients into a convenient Vitamin D3 + K2 Gummies supplement that contains 5,000 IU of vitamin D3 and 50 mcg of MK-7, an especially well-absorbed form of vitamin K2, to nourish your bones and your heart. You will want to make sure you test your vitamin D levels before starting supplementation and then again after a couple of months. “Test don’t guess” is always my motto in clinical practice to make sure you’re getting just the right amount of vitamin D3.

References:

1. Zhang W, Li L, Zhou X, et al. Concurrent Treatment with Vitamin K2 and D3 on Spine Fusion in Patients with Osteoporosis-Associated Lumbar Degenerative Disorders. Spine (Phila Pa 1976). 2022;47(4):352-360.
2. Iwamoto J, Takeda T, Ichimura S. Effect of combined administration of vitamin D3 and vitamin K2 on bone mineral density of the lumbar spine in postmenopausal women with osteoporosis. J Orthop Sci. 2000;5(6):546-551.
3. Somekawa Y, Chigughi M, Harada M, Ishibashi T. Use of vitamin K2 (menatetrenone) and 1,25-dihydroxyvitamin D3 in the prevention of bone loss induced by leuprolide. J Clin Endocrinol Metab. 1999;84(8):2700-2704.
4. Koshihara Y, Hoshi K, Ishibashi H, Shiraki M. Vitamin K2 promotes 1alpha,25(OH)2 vitamin D3-induced mineralization in human periosteal osteoblasts. Calcif Tissue Int. 1996;59(6):466-473.
5. Hara K, Akiyama Y, Tomiuga T, Kobayashi M, Nakamura T, Tajima T. [Influence of vitamin D3 on inhibitory effect of vitamin K2 on bone loss in ovariectomized rats]. Nihon Yakurigaku Zasshi. 1994;104(2):101-109.
6. Matsunaga S, Ito H, Sakou T. The effect of vitamin K and D supplementation on ovariectomy-induced bone loss. Calcif Tissue Int. 1999;65(4):285-289.
7. van Ballegooijen AJ, Pilz S, Tomaschitz A, Grübler MR, Verheyen N. The Synergistic Interplay between Vitamins D and K for Bone and Cardiovascular Health: A Narrative Review. Int J Endocrinol. 2017;2017:7454376.
8. El Borolossy R, El-Farsy MS. The impact of vitamin K2 and native vitamin D supplementation on vascular calcification in pediatric patients on regular hemodialysis. A randomized controlled trial. Eur J Clin Nutr. 2022;76(6):848-854.
9. Braam LA, Hoeks AP, Brouns F, Hamulyák K, Gerichhausen MJ, Vermeer C. Beneficial effects of vitamins D and K on the elastic properties of the vessel wall in postmenopausal women: a follow-up study. Thromb Haemost. 2004;91(2):373-380.
10. van Ballegooijen AJ, Cepelis A, Visser M, Brouwer IA, van Schoor NM, Beulens JW. Joint Association of Low Vitamin D and Vitamin K Status With Blood Pressure and Hypertension. Hypertension. 2017;69(6):1165-1172.
11. Kurnatowska I, Grzelak P, Masajtis-Zagajewska A, et al. Effect of vitamin K2 on progression of atherosclerosis and vascular calcification in nondialyzed patients with chronic kidney disease stages 3-5. Pol Arch Med Wewn. 2015;125(9):631-640.
12. Karamali M, Ashrafi M, Razavi M, Jamilian M, Akbari M, Asemi Z. The Effects of Calcium, Vitamins D and K co-Supplementation on Markers of Insulin Metabolism and Lipid Profiles in Vitamin D-Deficient Women with Polycystic Ovary Syndrome. Exp Clin Endocrinol Diabetes. 2017;125(5):316-321.