• Vitamin D
  

Vitamin D helps you absorb calcium from your food.

If you eat enough calcium, vitamin D helps to get the calcium into your bones to make them stronger. If you don’t eat enough calcium, vitamin D will pull calcium from your bones, which makes them weaker (1, 2).

Your body must maintain the right level of calcium in your blood even if your bones become weaker.

• Vitamin K

Vitamin K works with vitamin D to get calcium into the right place – your bones and not your blood vessels and soft tissues.

Osteocalcin is a protein that uses calcium to build your bones (3).

Osteocalcin cannot work without vitamin K. Matrix Gla protein (MGP) is another protein that prevents calcium from building up in your arteries and soft tissues, like organs (4).

• Bone Health
  

Studies show that healthy levels of both vitamin D and K support bone strength and lower the risk of broken bones (6).

In one study, the combination of low vitamin D and vitamin K levels was linked with a greater risk of a broken hip. There wasn’t a higher risk if the person was only low in one of the vitamins (7).

Another study on postmenopausal women showed that adding vitamin K to a vitamin D and calcium supplement increased bone density compared to the vitamin D and calcium supplement alone (8).

• Cardiovascular Health
  

Research shows that calcification of the arteries is linked to high blood pressure and heart disease because it causes the arteries to get stiff and hardened (9).

One study showed that the combination of low vitamin D and low vitamin K was linked with high blood pressure (10).

Although more research is needed, there are indications that supplementation of vitamin D and vitamin K together might benefit cardiovascular health (11).

• Vitamin D3 – Vitamin D has two main forms: D2 (ergocalciferol) and D3 (cholecalciferol). Vitamin D3 is the best choice for a vitamin D supplement because vitamin D3 raises vitamin D levels in the blood higher and keeps them there longer than vitamin D2 (13).

• Vitamin K2 – Vitamin K2 is the best choice for a vitamin K supplement. Research shows that higher intakes of vitamin K2 are linked with less buildup of calcium in the blood vessels and soft tissues more than vitamin K1 (14).

Another study concluded that a healthy intake of vitamin K2 could help prevent cardiovascular disease (15).

• MK-7 – MK-7 is the most effective type of vitamin K2 because of its higher bioavailability and longer half-life. Higher bioavailability means that more of the vitamin is absorbed and used by your body. A longer half-life means that the vitamin stays in your body longer (16).

In one study, rats that were given vitamin K2 supplements in the form of MK-7 had less cardiovascular buildup of calcium (17).

Another study found that long-term use of vitamin K2 supplements in the form of MK-7 improved the stiffness of arteries in healthy postmenopausal women (18).