Many first-time users of enzymes aren't quite sure whether they want to use serrapeptase or nattokinase, or whether maybe they really aren't the same thing.  Serrapeptase and nattokinase really are different enzymes, but their uses can complement each other.

The Stinky Bean that Makes the Enzyme

Nattokinase is an enzyme that was isolated about 30 years ago from a soybean food called natto. If you have ever eaten natto, chances are that you remember it. Connoisseurs of natto compare its aroma to a fine bleu cheese or the Australian yeast spread Vegemite, or maybe to Norwegian lutefisk or Swedish surströmming.

Personally, and I mean no offense to connoisseurs of natto, it reminds me of unwashed tennis shoes. The first time I was ever served natto was in a sports bar in Tokyo. My client seemed quite determined to show me that he was a he-man and I thought that maybe eating natto was some kind of test. In addition to its distinctive odor, natto is coated with fine strands of what looks a lot like clear mucus. The nanenane or goo on the beans drips off your chopsticks as you attempt to eat the beans without getting the goo all over your face.

I went through several napkins. I didn't feel that natto in my beard would really confirm my masculinity.

During the occupation of Japan after the last war, American officials banned the sale of natto on the assumption that it probably carried typhoid bacteria. They were wrong. Natto is actually an extraordinarily nutritious food.

The fermentation of the beans produces abundant quantities of vitamin K2, the vitamin that the body uses to make hormones that pull calcium into bones. It also releases a compound called picolinic acid, which neutralizes E. coli bacteria, even potentially deadly foodborne E. coli bacteria such as the O:157 strain. The beans are a nearly complete source of nutrition, and I have to believe that they have something to do with the fact that Japanese people usually don't overeat. But natto had been around for almost a thousand years before the discovery of nattokinase.

The Discovery of Nattokinase

The discovery of nattokinase is credited to Dr. Hiroyuki Sumi, who has become known as “Dr. Natto.” Dr. Sumi is actually much more of an advocate of natto as a food than he is an advocate of nattokinase as an enzyme supplement.

As Dr. Sumi tells his story, in the early 1980's the famous “Dr. Natto” had graduated from university and had started researching the use of another enzyme called urokinase as an anticoagulation agent, that is, as a non-pharmaceutical method of thinning blood. He would measure the anticoagulant power of urokinase samples by placing a sample of blood in a Petri dish, and then placing a sample of urokinase on the blood sample. He could measure the strength of the sample by the width of the blood that was dissolved by the enzyme.

One day Dr. Sumi was eating lunch at his desk. He dropped a tiny bit of natto into a Petri dish, and to his surprise, it started breaking down the blood sample. This observation led Dr. Sumi to isolate and identify the anticoagulant agent in natto as the enzyme nattokinase.

Daily consumption of natto and nattokinase may be part of the reason that Japanese people have much lower rates of heart disease and heart attacks than the rest of the world. Dr. Sumi, however, has his reservations about nattokinase supplements.

Nattokinase and Nattokinase Fragments

The reason Dr. Sumi is not necessarily a fan of nattokinase supplements is that there is a major difference between putting natto on a blood sample in the lab and taking a nattokinase supplement. Either nattokinase or natto itself has to pass through the digestive tract. The process of digesting natto or most nattokinase supplements lets some of the nattokinase enzyme pass through whole, but most of the nattokinase is dissolved into fragments.

Nattokinase fragments won't dissolve blood clots. But that does not mean that they have no health value at all. These “mini-enzymes” counteract a hormone made in the kidneys that is known as angiotensin. They keep antiotensin from being converted into another hormone known as angiotensinogen, which raises blood pressure. By acting as an angiotensin converting enzyme (or ACE) inhibitor, nattokinase fragments lower blood pressure.

Depending on how thoroughly nattokinase is digested in your stomach, taking the enzyme might reduce the your likelihood of developing blood clots and also lower your blood pressure. Eating natto, of course, does the same thing, except natto in food form also provides vitamin K which prevents deficiencies of clotting factors. Nattokinase the supplement just lowers blood pressure and usually reduces clotting factors. Natto does that and helps ensure that the anti-clotting effect does not cause excessive bleeding.

And it's the absence of vitamin K that causes Dr. Sumi concern about recommending nattokinase as an aid for cardiovascular health. If you eat at least 5 servings of green leafy vegetables per week, however, you will get enough vitamin K to prevent excessive effects of nattokinase even if you don't eat natto.

Nattokinase is a useful aid for cardiovascular health. Unlike serrapeptase, it lowers blood pressure. But it's not as powerful against clots as serrapeptase, and it's really not useful for supporting recovery from injuries to bones, tendons, ligaments, and muscles. Also if you take nattokinase, you can't take aspirin or prescription blood thinners. The results of combining nattokinase with these anticoagulant agents are impossible to predict.