Nattokinase and Blood Pressure

Natto has been used as a traditional folk medicine in Japan to treat high blood pressure, and recent studies confirm this benefit. In 1995, researchers studied the effects of nattokinase on high blood pressure in both animals and humans.
In one study, researchers gave volunteers with high blood pressure 30 grams of natto extract (equivalent to seven ounces of natto) every day for four days. In four out of five volunteers, systolic blood pressure dropped an average of 10.9 percent and diastolic blood pressure dropped an average of 9.7 percent.

In another study, researchers gave natto extract to rats. According to the data, the rats experienced an average 12.7 percent drop in systolic blood pressure after just two hours.

Retinal Vein Occlusion

In a 1994 case study, a team of researchers used nattokinase to treat a retinal vein occlusion. The blood vessels draining out of the eye of a 58-year-old Japanese man were blocked by a blood clot, and the blockage had caused bleeding and swelling in the eye, resulting in tiny vessels bursting. The researchers fed the man a 100-gram serving of natto – a rich source of nattokinase – before he went to bed every night. Ten days later, bleeding from the bottom of the man’s eye had stopped. After 20 days, the man’s vision recovered and he was sent home from the hospital with instructions to continue to eat natto twice a week. After two months, the occlusion had completely dissolved.


The body’s natural response to an arterial-wall injury caused by blood clots is to build up cholesterol in arterial plaques. Hence, by preventing blood clots, nattokinase may help prevent elevated cholesterol levels.


Certain types of diabetes have also been shown to be caused by changes in the blood vessels that supply the pancreas. These changes may be linked to small blood clots.

Forms and Dosage

As mentioned earlier, natto is the original source of nattokinase. However, thanks to modern technology, nattokinase is available in capsule form. A variety of anttokinase supplements are currently available, including a highly advanced supplement that contains no soy and no vitamin K (which promotes blood clotting).

Doses of nattokinase are measured in fibrin units (FU). Standard dosage recommendations are 2,000 FU (50 grams) daily for preventive use and 4,000 to 6,000 FU (160 to 200 grams) daily for therapeutic use.

For safety, those who use nattokinase for therapeutic purposes should choose a high-quality, well-researched nattokinase enzyme that is standardized for potency and guaranteed to be free of vitamin K.

Drug Interactions and Side Effects

Natto is a traditional food and is considered safe when eaten in moderate amounts. However, nattokinase enzymes and natto exracts that naturally contain vitamins K can interfere with blood-thinning drugs like warfarin and aspirin. People who are currently using blood thinners and those who suffer from kidney or liver disease should consult their doctor before using nattokinase.

People with bleeding disorders should not take nattokinase. People with ongoing bleeding problems, including ulcers, recent surgery or recent major trauma, should also avoid nattokinase.

Pregnant or nursing women should consult their doctors before using nattokinase until additional research confirms its safety.

The Bottom Line

Though its natural source is stinky and slimy, nattokinase has demonstrated some remarkable health-promoting qualities. Chief among them is nattokinase’s ability to improve circulatory health through its blood-thinning and anti-clotting properties. With heart disease and stroke among the most common killers in the United States, nattokinase may belong in your arsenal of disease-preventing supplements.

Could nattokinase be the next true breakthrough in cardiovascular health? Dr. Miler thinks so: “In all my years of research as a professor of cardiovascular and pulmonary medicine, natto and nattokinase represent the most exciting new development in the prevention and treatment of cardiovascular-related diseases, “ he said. “We have finally found a potent natural agent that can thin and dissolve clots effectively, and with relative safety and without side effects”.

Nattokinase Fast Facts

Uses and Benefits: Nattokinase helps promote cardiovascular health by preventing blood clots and supporting healthy blood pressure and cholesterol levels. Nattokinase may also provide benefits for diabetics.

Sources: Natto is the only dietary source of nattokinase. Because natto is an acquired taste, most people will prefer nattokinase capsules. Look for supplements with vitamin K. Sory-free nattokinase supplements are available for those with food sensitivities.

Special considerations: Vitamin K can interfere with the action of blood thinners like aspirin and warfarin, so people using these medications should avoid natto and nattokinase supplements with vitamin K. Do not use nattokinase if you have a bleeding disorder or if you have recently undergone surgery or experienced physical trauma. If you are pregnant, consult with your physician before using nattokinase.

Risk Factors for Cardiovascular Disease

Risk factors are traits that indicate a person’s likelihood to develop a disease. The more risk factors you have, the greater you risk. While some factors are hereditary, you can control many others. The following are common risk factors for cardiovascular disease:

• High cholesterol
• Family history
• High blood pressure
• Excess body weight
• Smoking
• Physical inactivity

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