Nattokinase: Its Uses, Health Benefits & Side Effects Have you heard of Nattokinase? Well, it’s this supplement that’s been getting pretty popular lately. They say it might be good for your health. Basically, it comes from this Japanese food called Natto made from fermented soybeans. People think it’s good for your heart, helps your blood flow, and makes your tummy happy. It’s getting a lot of buzz because it can help your body in many ways without taking meds. But, is Nattokinase good for the heart? Read on to find out as we delve into all the uses, health benefits & side effects of this amazing supplement.