Is Eating Natto Good for You? Benefits, Risks, and Nutrition

January 14, 2026 •

4 min read

In Japan, a high consumption of natto was linked to a lower risk of mortality in a 2020 study from the National Cancer Center. This sticky, pungent fermented soybean dish, rich in probiotics and unique enzymes, is gaining global attention for its potential health benefits, but many still wonder: is eating natto good for you?.

Quick Summary

This guide covers the impressive nutritional profile of natto, from its rich source of vitamin K2 to the powerful enzyme nattokinase. It details how this fermented superfood supports gut, heart, and bone health, while also explaining important considerations and potential risks for certain individuals.

Key Points

Rich in Vitamin K2: Natto is one of the most concentrated food sources of Vitamin K2, which is critical for directing calcium to bones and keeping it out of arteries.
Contains Nattokinase: A potent enzyme found in natto, nattokinase supports cardiovascular health by helping to dissolve blood clots and potentially lowering blood pressure.
Promotes Gut Health: As a probiotic-rich, fermented food, natto supports a healthy gut microbiome, which aids in digestion and strengthens the immune system.
Supports Bone Density: Regular consumption of natto is linked to higher bone mineral density and lower rates of bone loss, particularly in postmenopausal women.
High in Nutrients: Natto is a significant source of high-quality plant-based protein, dietary fiber, iron, magnesium, and other essential vitamins and minerals.
Acquired Taste and Texture: The strong smell and sticky, stringy texture can be challenging for some, but many people in Japan and worldwide enjoy it regularly.
Potential for Drug Interaction: Individuals on blood-thinning medication like warfarin should consult a doctor before consuming natto due to its high vitamin K2 content.

The Nutritional Powerhouse: What Makes Natto a Superfood?

Natto is a traditional Japanese food made by fermenting soybeans with the bacterium Bacillus subtilis. While its pungent smell and sticky, stringy texture might be off-putting to some, its nutritional benefits are undeniable. The fermentation process not only transforms the texture and flavor but also significantly boosts its nutrient profile, producing unique compounds not found in unfermented soybeans. This makes natto a potent source of vitamins, minerals, protein, fiber, and beneficial bacteria.

Key Nutrients and Bioactive Compounds in Natto

Vitamin K2 (Menaquinone-7): Natto is arguably the richest food source of Vitamin K2, a crucial nutrient for bone and heart health. The MK-7 form of K2, which is abundant in natto, is particularly effective at directing calcium to the bones and away from the arteries.
Nattokinase: This potent enzyme is produced during the fermentation process and has been shown to have blood-thinning properties. It helps dissolve blood clots and may support healthy blood pressure and improved circulation, protecting against cardiovascular diseases.
Probiotics: As a fermented food, natto is teeming with beneficial bacteria like Bacillus subtilis. These probiotics contribute to a balanced gut microbiome, which is essential for overall health, digestion, and a strong immune system.
Dietary Fiber: Natto is rich in both soluble and insoluble fiber, which aids digestion, promotes gut motility, and helps regulate blood sugar and cholesterol levels.
Complete Protein: Natto provides a high-quality, plant-based protein source containing all nine essential amino acids, making it a valuable food for vegetarians and vegans.

Significant Health Benefits of Eating Natto

The regular consumption of natto has been linked to several notable health outcomes, particularly in studies focused on the Japanese population.

Supporting Bone Health

Studies consistently show a strong link between natto intake and bone health, largely due to its exceptional Vitamin K2 content. In one cohort study, postmenopausal women who ate natto regularly experienced significantly lower rates of bone mineral density (BMD) loss. Another long-term study found that women who consumed natto daily had a nearly 50% lower risk of osteoporosis-related fractures. Vitamin K2's role in activating osteocalcin, a protein that binds calcium to bones, is central to this benefit.

Improving Cardiovascular Health

Natto’s effects on the heart are primarily driven by the nattokinase enzyme. Research has demonstrated that nattokinase has potent fibrinolytic activity, meaning it can break down fibrin, a protein involved in blood clot formation. This helps thin the blood, improve blood flow, and potentially reduce the risk of heart attack and stroke. Furthermore, natto's fiber and polyunsaturated fats can help manage cholesterol levels. Some studies even suggest nattokinase may help lower blood pressure.

Promoting Digestive Health

The fermentation process makes natto highly digestible by breaking down anti-nutrients present in soybeans. The probiotics in natto enrich the gut microbiome, leading to a healthier digestive system. This can help alleviate issues like constipation and bloating and improve nutrient absorption. A balanced gut microbiome is also linked to improved immune function, with studies showing that Bacillus subtilis can support the immune system.

Potential Risks and Considerations

While generally safe for most, some individuals should exercise caution when consuming natto.

Blood Thinners: Because of its high vitamin K2 content and nattokinase, natto has anticoagulant properties. People taking blood-thinning medication, such as warfarin, should consult a doctor before adding natto to their diet, as it can interfere with the drug's effectiveness.
Soy Allergies and Thyroid Function: As natto is made from soybeans, it is not suitable for individuals with a soy allergy. Soy is also considered a goitrogen, and while unlikely to affect healthy individuals, those with hypothyroidism may want to limit their intake or consult a healthcare provider.
Digestive Discomfort: For some people not accustomed to high-fiber foods, eating too much natto initially might cause digestive discomfort, such as gas or bloating. It's best to introduce it gradually into your diet.

How Natto Compares to Other Fermented Soy Products

Fermented soy products offer numerous health benefits, but natto stands out due to its unique fermentation process and resulting compounds.


Feature	Natto	Miso	Tempeh
Fermenting Agent	Bacillus subtilis	Aspergillus oryzae (Koji)	Rhizopus oligosporus
Primary Form	Whole, sticky, slimy beans	Paste	Cake of whole beans
Key Enzyme	Nattokinase	Proteases, amylases	Proteases, amylases
Unique Nutrient	Highest natural source of Vitamin K2 (MK-7)	High in salt, beneficial amino acids	Firm, high-protein structure
Texture	Distinctly sticky, stringy, and gooey	Smooth, thick paste	Firm, sliceable cake
Best For	Breakfast, mixed with rice or savory toppings	Soups, marinades, dressings	Grilling, baking, frying

Conclusion

Eating natto offers a wealth of potential health benefits, particularly for bone density, cardiovascular function, and digestive health. Its potent combination of Vitamin K2, nattokinase, and probiotics makes it a functional food with significant promise. However, individuals with certain medical conditions, especially those on blood thinners, should consult a healthcare professional before incorporating it regularly into their diet. For adventurous eaters, navigating the sticky texture and pungent flavor can lead to a nutritious and rewarding culinary experience.

How to Eat Natto for Maximum Benefits

Start small: Mix a little natto with rice and add soy sauce and mustard to mask the flavor.
Mix vigorously: Stirring the natto many times helps develop the frothy texture and enhance its unique flavor.
Add toppings: Experiment with chopped scallions, kimchi, or a raw egg yolk to find a combination you enjoy.
Incorporate into other dishes: For those who prefer to hide the texture, try adding natto to soups, sauces, or omelets.
Consume consistently: Regular, rather than large, sporadic servings are key to reaping the long-term benefits.

Where to Find Natto

Natto is commonly found in the refrigerated or frozen section of Japanese and other Asian supermarkets. You can also order it online from specialty food websites. Some health food stores also carry fresh or powdered forms.

Additional Research on Natto

Nattokinase: A Promising Alternative in Prevention and Treatment of Cardiovascular Diseases Intake of fermented soybeans, natto, is associated with reduced bone loss in postmenopausal women

Frequently Asked Questions

Natto is often described as having a pungent, earthy, or nutty flavor with a distinctive, sticky, and stringy texture. The taste is not as strong as the smell, which some liken to aged cheese or ammonia.

The stickiness, known in Japanese as neba-neba, comes from polyglutamic acid, a long-chain polypeptide produced by the Bacillus subtilis bacteria during fermentation. This gooey substance is highly valued by natto lovers.

Natto can be eaten at any time of day, but timing can offer different advantages. It is traditionally a breakfast food in Japan, often served with rice. Morning consumption can boost metabolism, while lunchtime may aid focus. Evening intake is sometimes linked to skin and tissue repair.

No, if you are taking anticoagulant medications like warfarin, you should consult your doctor before consuming natto. Natto's high vitamin K2 content can interfere with these medications' function.

While no single food guarantees weight loss, natto can be a healthy part of a weight loss plan. Its high fiber and protein content contribute to satiety, helping you feel fuller for longer, and its probiotics may aid in weight management.

Store-bought natto is typically found in the refrigerated or frozen section of Asian supermarkets. Keep it in the refrigerator in an airtight container. Frozen natto should be thawed before eating.

Natto is a unique superfood due to its high concentration of specific beneficial compounds. While tofu and miso offer their own health benefits, natto's exceptional levels of Vitamin K2 and the enzyme nattokinase set it apart for targeted benefits like bone and heart health.

Studies often show benefits with regular, consistent consumption, such as four or more servings a week. The standard individual serving size is a small, 40-50 gram container, so even a single serving daily or several times a week can be beneficial.

Yes, it is possible to make natto at home using soybeans and a special starter culture or a small amount of store-bought natto. However, the process requires careful temperature control and hygiene to ensure a successful fermentation.