Vitamin K2 helps maintain smooth arteries for optimal blood flow to the heart. Vitamin K2 and Vitamin D3 work hand in hand. Vitamin K is important because one of its normal functions is to help put calcium where it belongs, into bones, and the right balance in arteries and soft tissues. Vitamin D is your body"s natural signal for optimal absorption of calcium into your bones and teeth. So use these two vitamins in our Spring Valley combination the way nature intended: together.