Vitamin K contributes to the maintenance of normal bones and the Vitamin K2 form stays in the blood for longer than Vitamin K1. It also contributes to normal blood clotting. Vitamin K2 is highly bio-available and bio-active, and remains in the blood for longer than K1. This means the bodys reserves can be built up and tissues supplied continuously. An excellent food source of Vitamin K2 is natto (fermented soya beans) ndash; not a common Western dietary choice. Cheese and curd are also good sources, but people following a heart-health diet are recommended to reduce such foods in their diet, and theyre usually high in salt. Higher Natures Vitamin K2 is sourced from natto. As Vitamin K is so important for bone health it makes sense to take this as part of your daily supplementation programme especially if you are postmenopausal. The optimal daily intake as determined by research is 45micro;g ndash; more is not necessary. Highly bio-active and bio-available. The average western diet is depleted in vitamin K2, important for normal blood clotting. Helps maintain bone mass in post menopausal women. Vitamin K2 remains in the blood for longer than K1. Research shows that optimal daily intake is 45micro;g.