Nattokinase is an enzyme derived from natto, a traditional Japanese food made from fermented soybeans. Many people seek out this enzyme for its cardiovascular benefits, a system closely linked to kidney function. The core question is whether Nattokinase’s systemic effects translate into a specific, measurable benefit for the kidneys. Examining the enzyme’s mechanism and current scientific evidence helps clarify its potential role and necessary safety precautions for individuals with compromised kidney function.
What is Nattokinase and How Does It Work?
Nattokinase is a serine protease, a type of protein-breaking enzyme. It is isolated from the sticky substance produced when Bacillus subtilis var natto ferments boiled soybeans. Its primary and most studied function is its powerful fibrinolytic activity, meaning it can directly break down fibrin. Fibrin is a protein that forms the mesh-like structure responsible for stabilizing blood clots.
This enzyme acts much like the body’s own clot-dissolving enzyme, plasmin, and is considered several times more active in laboratory settings. Nattokinase works both directly by dissolving fibrin and indirectly by inactivating plasminogen activator inhibitor-1 (PAI-1). Reducing PAI-1 enhances the body’s natural ability to produce plasmin, which promotes the breakdown of clots. This dual action supports healthy blood flow and reduces blood viscosity.
The Theoretical Link Between Nattokinase and Renal Health
The theoretical benefit of Nattokinase for the kidneys stems from its influence on the circulatory system. The kidneys are highly vascular organs, packed with millions of tiny filtering units called glomeruli, which are networks of delicate microvessels. For the kidneys to effectively filter waste from the blood, blood pressure must be carefully managed, and the microvasculature must remain clear and unobstructed.
Nattokinase’s ability to lower blood pressure and reduce the risk of clot formation is theorized to alleviate strain on these fragile renal filtering units. High blood pressure is a leading cause of kidney damage because it stresses the small blood vessels, leading to scarring and reduced function. By supporting healthy blood pressure levels, Nattokinase may protect the long-term integrity of the glomeruli and help maintain a healthy glomerular filtration rate (GFR). Furthermore, its anti-thrombotic effect could prevent micro-blockages that might otherwise impair blood flow to the renal tissue.
Current Research on Nattokinase and Specific Kidney Conditions
Research has transitioned from theory to specific findings, particularly concerning conditions that often precede kidney failure. Several human trials have demonstrated that Nattokinase supplementation can reduce both systolic and diastolic blood pressure. In one study, the reduction in diastolic blood pressure was statistically significant compared to a placebo group, a relevant finding since hypertension accelerates kidney disease progression.
An animal study using diabetic rats, a model for diabetic nephropathy, provided more direct evidence of renal protection. High-dose Nattokinase significantly inhibited the accumulation of glycogen in the renal tubules and reduced circulating levels of advanced glycation end products (AGEs). AGEs are damaging compounds that accumulate in diabetes and contribute to kidney injury, suggesting a direct protective mechanism in this specific disease model.
In the context of end-stage renal disease, Nattokinase has been investigated as an adjuvant therapy. One study explored combining it with heparin during hemodialysis, suggesting that the enzyme could safely reinforce the necessary anticoagulant activity in patients with chronic kidney disease (CKD) who have a prothrombotic profile. However, there is currently no strong scientific evidence suggesting Nattokinase can directly reverse existing kidney damage or significantly alter established markers of impaired renal function like Cystatin C.
Safety Guidance for Individuals with Impaired Kidney Function
The primary consideration for individuals with impaired kidney function is the enzyme’s potent blood-thinning effect. Nattokinase may increase the risk of bleeding, especially when taken alongside prescription anticoagulants (like warfarin) or antiplatelet medications (such as aspirin). Individuals with existing bleeding disorders or those recovering from recent surgery should avoid using Nattokinase.
Consulting a nephrologist or healthcare provider is necessary before starting Nattokinase. A medical professional can assess the risk of bleeding based on the patient’s current medications and the severity of their kidney impairment. It is also important to note that while purified Nattokinase supplements are generally free of Vitamin K, the raw food natto contains high levels of Vitamin K, which can interfere with the action of certain blood thinners.