There are three K-complex vitamins: K1 (phylloquinone), K2 (menaquinone) and K3, a synthetic form of this vitamin. Some studies have shown that vitamin K3 had toxic effects on the liver. Although vitamin K1 is readily available in leafy vegetables, the bacteria in our intestines do not convert enough of it into K2 to help with atherosclerosis and osteoporosis. Vitamin K2 is present in foods such as natto, made from fermented soybeans and commonly consumed in Japan, as well as in butter, meat, egg yolk and offal from animals fed on pasture rather than grain. Since products from grass-fed animals are rare these days, and the taste of natto is not easy for Westerners to acquire, a K2 vitamin supplement is the best way to ensure you get the optimal daily dose of this important nutrient.
Most people will find it difficult to meet their daily vitamin K2 requirements through diet alone. Natural Factors Vitamin K2 provides highly bioavailable MK-7, derived naturally from natto, making it easy to get more of this important nutrient.