Common Names
- Natto extract
- Fermented soybeans
For Patients & Caregivers
How It Works
Nattokinase may help prevent clot formation and reduce blood pressure. It has not been tested as a cancer treatment in humans.
Nattokinase is an enzyme produced from nattō, a traditional Japanese food made from soybeans fermented with the bacterium, Bacillus subtilis. Lab studies suggest it can break down fibrin in the blood that forms clots or affect some factors that characterize Alzheimer’s disease. Human studies are limited, and suggest nattokinase may reduce high blood pressure. Although nattokinase has been promoted as an alternative anticancer treatment, clinical studies have not been conducted.
Nattokinase may increase the risk of bleeding in patients when used with blood-thinning drugs.
Purported Uses
- To prevent blood clots Preliminary studies suggest that nattokinase may prevent deep vein thrombosis.
- To reduce high blood pressure Preliminary studies suggest nattokinase may lower blood pressure.
- Alzheimer’s disease Although animal models suggest nattokinase may degrade amyloid plaques, human studies have not been conducted.
- Cancer treatment Although nattokinase is promoted as an alternative cancer treatment, clinical data of its effectiveness are lacking.
Patient Warnings
Do Not Take If
Side Effects
For Healthcare Professionals
Clinical Summary
Nattokinase is an extracelluar enzyme secreted by the bacterium Bacillus subtilis, used to ferment boiled or steamed soybeans resulting in a preparation called nattō. Nattō has been consumed as food in Japan for several centuries. Nattokinase is also available as a supplement and is most known for its effects on prevention and treatment of clots and to improve blood circulation.
Preliminary studies have explored its antithrombotic and amyloid-plaque degrading abilities (1) (2) (4) (5) (9). Nattokinase decreases platelet aggregation and thrombus formation in a dose-dependent fashion both in vitro and in vivo (6) (7). Reduced intimal thickening was observed in the femoral artery of rats that were fed a diet containing nattō (8).
Studies in humans are limited. In a randomized double-blind trial, nattokinase capsules reduced diastolic and systolic blood pressure in prehypertensive patients (3). In subjects with hypercholesterolemia, nattokinase altered hemostatic factors (19).
Nattokinase has been promoted as an alternative anticancer treatment based on the notion that it can help dissolve the fibrin coating around a tumor, and increase oxygen supply in the blood to inhibit cancer cell growth. However, these mechanisms have not been proven in humans.
Theoretically, nattokinase may increase bleeding risk when used with anticoagulant, antiplatelet, and fibrinolytic drugs. Raw nattō contains high levels of vitamin K that may interfere with the action of warfarin (15).
Mechanism of Action
In vitro studies show that nattokinase decreases clot formation by cleaving and inactivating the plasminogen activator inhibitor (PAI) via proteolysis at P1-P1’ peptide bond. PAI is a key inhibitor of tissue plasminogen activator (tPA) that converts plasminogen to plasmin. PAI inactivation allows for greater tPA activity and increased lysis of clots (10) (11). In the absence of PAI, nattokinase affects direct proteolysis of fibrin; however, this effect is less than the protelysis achieved by the PAI-mediated pathway (2). The fibrinolytic activity of nattokinase is estimated to be four-fold that of plasmin (12).
Nattokinase is currently being evaluated for its potential as an amyloid plaque-degrading agent. Low doses of nattokinase have been shown to increase expression of the ADAM10 gene, which belongs to a family of proteinases that degrade the amyloid precursor protein. Upregulation of ADAM10 may shift the amyloidogenic pathway to the non-amyloidogenic pathway. This activity may prevent amyloid plaque accumulation that characterizes Alzheimer’s disease (9).
Warnings
Theoretically, nattokinase can cause an existing clot to dislodge due to its fibrinolytic property, resulting in a stroke or embolus at a distal location. Patients with a history of deep vein thrombosis should avoid of use nattokinase (5).
Contraindications
Patients with coagulation disorders and those currently undergoing anticoagulant, fibrinolytic, or antithrombotic treatments should avoid nattokinase (2).
Adverse Reactions
None reported, but for some it may increase bleeding risk when used with blood-thinning drugs or affect lab results.
Case Report
Dyspnea, mild chest pain, and thrombus on mechanical valve: With long-term self-substitution of nattokinase for warfarin after aortic valve replacement, requiring a repeat valve replacement (16).
Herb-Drug Interactions
- Aspirin: Nattokinase may increase the risk of intracerebral hemorrhage (14).
- Anticoagulant/antiplatelet/fibrinolytic drugs: Theoretically, nattokinase may increase the risk of bleeding. In a small study of healthy young men, enhanced fibrinolysis and antithrombosis after a single-dose of oral nattokinase occurred, although effects in this group were deemed to be within normal range (17). Laboratory studies indicate that nattokinase is a heparin-binding protein with a binding affinity of approximately 250 nM. The interaction is chain-length dependent, and NK also interfered with heparin interactions with antithrombin and fibroblast growth factors (18).
- Warfarin: Nattō is rich in vitamin K. In addition, Bacillus subtilis bacteria in natto continue synthesizing vitamin K in the intestine following consumption, which can reduce the effects of warfarin (15).