Nattokinase Foods: Is Natto the Only Natural Source?

Is natto the only food with nattokinase? Discover which fermented foods contain this unique enzyme and how to get consistent daily intake.

Nattokinase Foods

If you've been researching natural ways to support heart health, circulation, and healthy aging, you've probably come across nattokinase. This powerful enzyme has become increasingly popular among people looking to support cardiovascular wellness naturally. But one question comes up repeatedly: what foods contain nattokinase?

The answer may surprise you. While many fermented foods offer impressive health benefits, nattokinase is actually much rarer than most people realize. In fact, if you're specifically looking for nattokinase foods, there is one food that stands far above all others.

In this guide, we'll explore the natural food sources of nattokinase and help you determine the best way to incorporate nattokinase into your wellness routine.

What Is Nattokinase?

Nattokinase is a naturally occurring enzyme produced during the fermentation of soybeans into a traditional Japanese food called natto.

The enzyme was first identified by Japanese researcher Dr. Hiroyuki Sumi, who discovered its remarkable fibrin-degrading activity. Fibrin is a protein involved in blood clot formation, which is one reason nattokinase has attracted significant scientific interest in cardiovascular health research.

Nattokinase is produced by a specific bacterium known as Bacillus subtilis natto. During the fermentation process, this beneficial microorganism transforms cooked soybeans into natto while generating the enzyme known as nattokinase.

Today, nattokinase is widely studied for its potential role in supporting:

What Foods Contain Nattokinase?

The Short Answer

If you're searching for nattokinase foods, the direct answer is simple:

Natto is the only food known to naturally contain significant amounts of nattokinase.

While many fermented foods contain beneficial probiotics, enzymes, and bioactive compounds, none have been shown to contain meaningful levels of nattokinase comparable to natto.

Natto: The Original Nattokinase Food

Natto is a traditional Japanese food made by fermenting soybeans with Bacillus subtilis natto.

The finished product has a distinctive appearance characterized by:

  • Sticky strands

  • Strong aroma

  • Savory flavor

  • Soft texture

In Japan, natto has been consumed for centuries and is often eaten for breakfast over rice with soy sauce, mustard, or green onions.

Because nattokinase is produced during the fermentation process, natto remains the richest natural dietary source available.

Do Other Fermented Foods Contain Nattokinase?

Nattokinase

This is where many people become confused.

Fermented foods are often grouped together, leading some to assume that all fermented products contain nattokinase. However, fermentation alone does not create nattokinase.

Different foods use different microorganisms, and each microbe produces its own unique compounds.

Here's how common fermented foods compare:

Food

Fermented?

Contains Significant Nattokinase?

Natto

Yes

Yes

Tempeh

Yes

No

Miso

Yes

No

Soy Sauce

Yes

No

Kimchi

Yes

No

Sauerkraut

Yes

No

Yogurt

Yes

No

Kefir

Yes

No

Tempeh

Tempeh is another fermented soybean product, but it uses fungal cultures rather than Bacillus subtilis natto. As a result, it does not produce meaningful nattokinase.

Miso

Miso contains beneficial compounds from fermentation but is not considered a significant source of nattokinase.

Kimchi and Sauerkraut

These fermented vegetables support gut health and provide probiotics, but they do not contain nattokinase.

Yogurt and Kefir

Although rich in beneficial bacteria, dairy fermentations use entirely different microorganisms and do not generate nattokinase.

Why Is Natto Unique?

The reason natto stands alone among nattokinase foods comes down to microbiology.

Nattokinase is produced specifically by Bacillus subtilis natto under precise fermentation conditions.

Without this exact bacterial strain, nattokinase is not generated in meaningful amounts.

Think of it like baking bread. Different ingredients and processes produce completely different results. Similarly, different fermentation cultures create different enzymes.

The special relationship between soybeans and Bacillus subtilis natto is what makes natto such a unique functional food.

How Much Nattokinase Is in Natto?

The amount of nattokinase in natto varies depending on:

  • Fermentation conditions

  • Manufacturing methods

  • Storage practices

  • Age of the product

Unlike supplements, which are standardized and measured in Fibrinolytic Units (FU), natto's nattokinase content can fluctuate considerably.

This variability creates challenges for individuals who want consistent daily intake.

Additionally, cooking may reduce enzyme activity. Since nattokinase is a protein enzyme, excessive heat can potentially affect its potency.

For this reason, many people consume natto fresh rather than cooked.

Why Many People Don't Eat Natto Regularly

Despite its nutritional value, natto remains a difficult food for many Western consumers.

Common barriers include:

  • Strong Aroma: Natto has a pungent smell that some people find overwhelming.

  • Sticky Texture: The fermented soybeans produce long, stringy strands that many first-time eaters find unusual.

  • Acquired Taste: Even individuals who enjoy fermented foods often need time to develop a taste for natto.

  • Limited Availability: While easier to find than in the past, natto still isn't available in every grocery store.

These challenges explain why many health-conscious consumers look for alternative ways to obtain nattokinase.

Natto vs Nattokinase Supplements

Natto vs Nattokinase Supplements

Both natto and nattokinase supplements offer advantages.

Feature

Natto

Nattokinase Supplement

Source

Fermented soybeans

Purified nattokinase

Taste

Strong

None

Dosage consistency

Variable

Standardized

Convenience

Moderate

High

Daily tracking

Difficult

Easy

Soy content

High

Typically minimal

Availability

Limited

Widely available

Benefits of Natto

Natto provides more than just nattokinase.

It also contains:

  • Protein

  • Fiber

  • Probiotics

  • Vitamin K2

  • Minerals

  • Bioactive peptides

For individuals who enjoy the food, natto can be a nutritious addition to a healthy diet.

Benefits of Supplements

Supplements offer:

  • Consistent potency

  • Convenient dosing

  • No taste concerns

  • Standardized enzyme activity

  • Easier long-term adherence

For many people, supplements are simply more practical.

Potential Health Benefits Associated With Nattokinase

Research into nattokinase continues to grow, particularly in cardiovascular wellness.

Healthy Circulation Support

One of the primary reasons people seek nattokinase foods is support for healthy circulation.

Efficient blood flow helps transport oxygen and nutrients throughout the body and supports overall cardiovascular function.

Fibrin Breakdown Activity

Nattokinase is best known for its ability to break down fibrin.

Fibrin plays an important role in clot formation, making this activity one of the most studied aspects of nattokinase.

Blood Pressure Support

Several studies have explored nattokinase's potential role in supporting healthy blood pressure already within normal ranges.

Researchers continue investigating the mechanisms involved.

Healthy Aging

Circulatory health becomes increasingly important with age.

As interest in longevity grows, nattokinase has gained attention among individuals focused on maintaining cardiovascular wellness throughout the aging process.

Is Eating Natto Better Than Taking Nattokinase?

There is no universal answer.

The best option depends on your goals.

Choose Natto If You Want:

  • Whole-food nutrition

  • Probiotics

  • Vitamin K2

  • Traditional Japanese cuisine

  • Additional protein and fiber

Choose a Supplement If You Want:

  • Consistent dosing

  • Convenience

  • No strong taste

  • Standardized potency

  • Easy daily use

Quick Comparison

Goal

Best Option

Whole-food nutrition

Natto

Consistent enzyme intake

Supplement

Maximum convenience

Supplement

Traditional dietary approach

Natto

High-potency dosing

Supplement

Many people actually use both approaches, enjoying natto occasionally while relying on supplements for consistent intake.

How to Add Natto to Your Diet

Add Natto to Your Diet

If you'd like to try the original nattokinase food, consider the following tips.

Where to Buy Natto

Look for natto in:

  • Asian supermarkets

  • Japanese specialty stores

  • Health food retailers

  • Online grocery services

It is typically sold refrigerated or frozen.

Beginner-Friendly Ways to Eat Natto

First-time eaters often enjoy natto when combined with:

  • Steamed rice

  • Green onions

  • Soy sauce

  • Mustard

  • Sushi bowls

  • Avocado

Mixing natto thoroughly before eating can improve texture and flavor.

Storage Tips

  • Keep refrigerated

  • Freeze for longer storage

  • Consume before expiration

  • Avoid excessive heating

Who Should Avoid Nattokinase?

While nattokinase is generally well tolerated, certain individuals should consult a healthcare provider before consuming natto or nattokinase supplements.

  • Individuals Taking Blood Thinners: Because nattokinase may affect clotting pathways, people using anticoagulants or antiplatelet medications should seek medical guidance.

  • Before Surgery: Healthcare providers may recommend discontinuing nattokinase before surgical procedures.

  • Soy Allergies: Since natto originates from soybeans, individuals with soy allergies should avoid it.

  • Pregnancy and Breastfeeding: There is limited research in these populations, making professional medical guidance especially important.

Final Verdict: Is Natto the Only Natural Source of Nattokinase?

For anyone searching for nattokinase foods, the evidence points to a clear conclusion: natto is the only significant natural food source of nattokinase.

While other fermented foods can be excellent additions to a healthy diet, they do not provide meaningful amounts of this unique enzyme. If your primary goal is increasing nattokinase intake, natto remains the gold standard.

However, because natto's taste, texture, availability, and enzyme content can vary, many people choose a standardized supplement instead. High-potency options such as Healthletic Ultimate Nattokinase offer a convenient alternative, delivering a verified 10,800 FU clinical-strength dose in delayed-release capsules designed to maximize absorption. Whether you choose natto, supplements, or a combination of both, understanding where nattokinase comes from can help you make more informed decisions about your cardiovascular wellness strategy.

Maria Morgan-Bathke, PhD, RD

PhD in Nutritional Sciences | MBA (Health Care Management) | Registered Dietitian

Maria holds a B.S. in Dietetics from UW–Stout, a Ph.D. in Nutritional Sciences from the University of Arizona, and an MBA in health care management from Viterbo University. She completed a Medical Nutrition Therapy–focused dietetic internship at Carondelet Health System and a postdoctoral fellowship at the Mayo Clinic in the Endocrine Research Unit with Dr. Michael Jensen.

She is an Associate Professor, Department Chair, and Dietetic Internship Director at Viterbo University, an Adjunct Professor at Saybrook University, and a Registered Dietitian for Nourish. She is also the founder of Dr. Maria’s Nutrition and Wellness. Her research interests include obesity and weight management, inflammation, insulin signaling, cardiometabolic health, and women’s health.

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