|Natto on rice. Source: Shades0404 (CC: 2.5)|
So where exactly can we get vitamin K2, especially the MK-7 form? Besides supplements, natto and some types of cheese are sources of MK-7. Natto is a fermented soy food from Japan, and although it's very much an acquired taste, it is the best source of the best vitamin K. Some types of meat, cheese and eggs contain the MK-4 form, which is still effective, although less active. Green leafy vegetables contain vitamin K1, and are our main source of dietary vitamin K in the West. This is much less active than vitamin K2 and mainly supports homeostasis. Finally, the MK-10 and MK-13 forms of vitamin K2, which are produced by colonic bacteria, are poorly absorbed and do not provide much activity. While more research on vitamin K2 and RA are probably needed, its use against the disease looks promising, and maybe it's time to suck it up and learn to like natto.