Vitamin D controls the absorption of calcium into the blood. Vitamin K2 controls where that calcium ends up. Over-supplementation of vitamin D3 without ample vitamin K2 leads to problems of excess calcium. If calcium isn’t laid into bone, it will find itself in other tissues, like your arteries.

For people already taking vitamin D, adding vitamin K might be protective. Vitamin D can cause increased levels of calcium in the blood, which may lead to mineral deposits in blood vessels that can increase the risk of heart disease. Some supplement manufacturers claim taking vitamin K along with your vitamin D might decrease such risks.

Vitamin D alone can lead to excessive calcium uptake, tissue deposition, and interference with normal cardiac and renal function. By conscientiously using vitamin K2 in conjunction with D3, calcium is absorbed and directed toward healthy functions in the body.9 What Does Vitamin K2 Do? Vitamin K activates several essential proteins in the body.