One of the main challenges of the vegan is making sure to get enough
vitamin K2, or as Weston A. Price called it activator X, in the diet.
Vitamin K2 is required to keep calcium going to, and staying in the
places that are necessary for it to be. Without it, calcium can leach out
of the bones and teeth, leading to osteoporosis, and accumulate in
soft tissues where it need not be, causing kidney stones, bone spurs,
breast tissue calcification, and arterial calcification which can lead
to hardening of the arteries, and leading to heart attack and stroke.

Vegetarians, may want to try grass fed butter, or clarified butter (ghee)
also grass fed. The only currently known vegan source of vitamin K2
other than synthetics is a fermented food, from Japan, called natto.
Natto is a ferment of soybeans. The troubles with soybeans are
multitude. 94% of soybeans are GMO, in the U.S.A., since 2016. Most
GMO soybeans are not organic, the majority being 'roundup ready'.

Soy is also a producer of phytoestrogens, which cause disruption of
the hormone balance in the body. The fermentation process may lower
the levels of phytoestrogens, but I have seen no studies confirming this.
This does not mean the studies do not exist, I am still looking.

Next, there are the lectins, or soybean agglutinins, which are
antinutrients that chelate minerals. In addition, there are phytates and
phytic acid which also chelate minerals, and suppress enzyme function
as a result. Fermentation may also decrease the amount of phytates.
More study is needed.

Natto, yummm.

It is possible that other types of beans may be used in the fermentation
process which may produce K2, black turtle beans among them. These
may still contain phytoestrogens and/or lectins and/or phytates because
they are fermented and not cooked.

Gouda and brie, and some types of blue cheeses contain K2 as a
product of the bacterial action in the cheese making process, so
it is not necessary for it to be made from grass fed milk. Those with milk
sensitivities may still want to avoid these, grass fed or no.

Grass fed butter, goose liver (also not necessarily grass fed), and fowl
and fish eggs are also sources of K2.

Green leafy vegetables contain K1, but not K2. There is a small amount
of conversion of K1 to K2 in the body, but not enough to meet dietary
requirements. K2 also comes in different forms MK-4 to MK-10. MK-4
from animal products, and the MK-7 from fermentation. The others are
not much elaborated upon.

Vitamins A and D3, magnesium, phosphorus and potassium balances all
benefit from the presence of K2.

This subject expands the more I look into it. This post is merely a
beginning. Please leave comments below.

https://blog.bulletproof.com/106-the-powers-of-vitamin-k2-with-dr-kate-rheaume-bleue-podcast/

Podcast #106 - The Powers of Vitamin K2 w/ Dr. Kate Rhéaume-Bleue

Here is another lecture, a little bit more in depth.

Dr. John Whitcomb Seminar - Vitamin K2
Super Vitamin, Hidden Before Our Eyes

images: nutritionadvance.com/wp-content/uploads/2016/09/vitamin-k2-benefits.jpg
www.ers.usda.gov/webdocs/charts/58020/biotechcrops2016.png?v=42565
blog.sudy.co.hu/wp-content/uploads/2015/06/natto3.jpg
videos: www.youtube.com/watch?v=auZCWICR4Ds
www.youtube.com/watch?v=jPWCJxyHAg4