An interesting study of nattokinase, which is an enzyme produced in natto during fermentation of soybeans:
Supplementation for a year of nattokinase raised HDL, lowered triglycerides, and reduced thickness of plaque.
Nattokinase is in natto, and you can make your own:
I’ve been doing this, making my own natto. It’s a challenging recipe. I’ve had to increase the starter to 1/8 teaspoon, and make the layers be thin. That is, I use wide glass containers, as the thinner the beans are, the more they seem to ferment better. Even with that, one container comes out with white film on it, and the other container doesn’t have nearly as much. Could be related to thickness, but it’s the best I can do with the containers I have.
I take the results of both containers, mix them up, put them in the fridge for a week before I use them.
Unfortunately, I can’t figure out whether the amount you’d get in natto is anywhere near what they used. The FU unit, in particular, is hard to translate to what nattokkinase is in natto. And I eat natto less then every day, usually just a few days a week.