Nattokinase Explained Simply

1. What Is Nattokinase?

Nattokinase is a protein that is formed when soybeans are fermented. In the process, bacteria convert the beans, similar to yogurt. The enzyme belongs to the group of serine proteases (protein cleavers). These can break down other proteins in the body. In Japan, the fermented beans are eaten as natto. As a dietary supplement, nattokinase is available mostly as a capsule or tablet.

2. Where Is It Found, and What Is It Made From?

Nattokinase is found in natto, a traditional Japanese dish made from fermented soybeans. It is produced by fermenting cooked soybeans with certain bacteria. From this mass, the enzyme is filtered out, purified and dried into powder. In this form it comes in capsules, tablets or powder for ingestion. Mixtures with other substances also exist.

3. What Does Nattokinase Do? What Research Shows

Blood Pressure

In adults with elevated blood pressure, several studies and a summary of several studies showed improvements. Mainly capsules with nattokinase extract were studied. One study examined a combination preparation with red yeast rice; this result cannot be attributed to nattokinase alone 2. The strength of evidence is high, but there are only a few studies so far and the observation period was short. Whether blood pressure falls permanently is open.

Blood Fluidity

A study with twelve healthy men found longer clotting times and lower factor VIII activity after a single administration, in each case within the normal range 8. In adults with elevated cholesterol, certain clotting times were prolonged more than with placebo (sham treatment) 11. These are laboratory values, not a proven effect on blood flow. In nine healthy men, the hands rewarmed faster after a cold water bath following a single administration than with a sham treatment 9. Capsules were studied; data on other forms are lacking. The strength of evidence is moderate, the studies are short.

Fibrinolysis

Fibrinolysis means that the body dissolves blood clots. A study in twelve healthy young men found greater breakdown of fibrin after a single administration of nattokinase capsules 8. These are laboratory findings, not a proven effect in patients. All values remained within the normal range. The strength of evidence is low; data on other forms and on sick people are lacking.

Blood Lipids

Favorable findings on cholesterol and blood lipids come from mixtures of nattokinase with red yeast rice or Monascus 247. These results cannot be attributed to nattokinase alone. A summary of several studies found no improvement in blood lipids for nattokinase alone, in part even less favorable values 1. Also in a study without a comparison group, the blood lipids remained unchanged 15.

Heart and Circulation

A study of a mixed preparation of nattokinase and Monascus found no difference in vessel wall thickness in patients with a lipid metabolism disorder 4. This result cannot be attributed to nattokinase alone. In nine healthy men, a single administration of nattokinase did not change heart rate and cardiac output differently from a sham treatment 9. Events such as heart attack or stroke were not examined.

Thrombosis

A study in 178 patients with coronary artery disease found more favorable clotting laboratory values than with placebo only under a mixture of nattokinase and red yeast rice 2. These are laboratory values, not a proven effect against thromboses. A case series (description of several individual cases) reports improvement of symptoms, but without a comparison group and partly together with anticoagulants 14. A case report describes a blood clot on a heart valve prosthesis after a patient had replaced his anticoagulant himself with nattokinase 17.

Inflammation

In a study, people with a preliminary stage of diabetes received a mixture of aronia, red ginseng, shiitake mushroom and a little nattokinase 10. The measured inflammation value did not differ clearly from that of a sham treatment. Whether nattokinase alone influences inflammation values remains open.

Other Investigations

In this area, nattokinase preparations were studied in several studies on various questions, predominantly as capsules. With slightly elevated blood pressure, the laboratory value renin, which is involved in blood pressure regulation, fell more than with placebo 5. In asymptomatic narrowing of the carotid or cerebral arteries, nattokinase did not improve general thinking ability; only an additional analysis found better spatial perception 3. In a further study, nattokinase served only as a comparison preparation; under it, shoulder stiffness, back pain and cold hands and feet did not improve 12. The findings come from individual studies, mostly from laboratory values.

4. How Was Nattokinase Taken in the Studies?

In studies, nattokinase was taken predominantly as a capsule with extract, partly with a stated enzyme activity. Tablets and combination preparations with other ingredients were also examined 256. Natto as a food and powder for ingestion were hardly studied in comparative trials. The stated enzyme activity and the amount differ between the preparations, which is why they are difficult to compare.

5. Is Nattokinase Safe? Side Effects in the Studies

A summary of several studies found no notable adverse events from nattokinase 1. No side effects were reported with combination preparations containing red yeast rice or Monascus either 24. A case report describes a blood clot on a heart valve prosthesis after a patient had replaced their anticoagulant with nattokinase on their own 17. The authors explicitly advise against taking nattokinase as a substitute for anticoagulants 17. Since nattokinase prolonged clotting time in studies 811, an additional effect together with anticoagulants is conceivable; an overview mentions a possible bleeding risk 19.

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