Vitamin K2 also lasts for several days in your bloodstream compared to K1 which mostly disappears in a few hours.

Foods that include reasonable amounts of vitamin K1 include leafy vegetables, olive oil, cheese, liver, soy beans, brussels sprouts, broccoli, cauliflower, coffee, and green tea. More than 80% of the Vitamin K in western diets consists of vitamin K1. The more beneficial form, K2, is difficult to find in your diet with the exception of the Japanese traditional food, Natto1

Natto – the Food of the Samurai Warrior, Builds Your Bones
http://www.algaecal.com/vitamin-k2.html