Natto Benefits: 7 Science-Backed Reasons to Eat This Fermented Superfood

Natto is a traditional Japanese superfood made from fermented soybeans that has been consumed for over 1,000 years. Despite its distinctive smell and sticky texture, this nutrient-dense food offers remarkable health benefits that are increasingly recognized by nutrition experts worldwide.

From supporting cardiovascular health to strengthening your immune system, natto provides a unique combination of probiotics, vitamins, minerals, and bioactive compounds that can significantly impact your overall wellness. This comprehensive guide explores the science-backed benefits of natto and why you should consider adding it to your diet.

What Is Natto and How Is It Made?

Natto is created through the fermentation of whole soybeans using the beneficial bacteria Bacillus subtilis. This fermentation process typically takes 24 hours and transforms ordinary soybeans into a powerful nutritional powerhouse with a distinctive stringy, sticky texture.

The fermentation process not only enhances the nutritional profile of soybeans but also produces unique compounds like nattokinase—an enzyme with remarkable health-promoting properties. Traditionally wrapped in rice straw, modern natto production uses controlled fermentation environments to ensure consistency and food safety.

In Japan, natto is commonly eaten for breakfast, served over steamed rice and topped with soy sauce, mustard, and green onions. While the strong aroma and unusual texture may be off-putting initially, many people develop a taste for this nutritious food over time.

Impressive Nutritional Profile of Natto

One of the primary reasons natto is considered a superfood is its exceptional nutrient density. A 100-gram serving (approximately 3.5 ounces) of natto provides:

• Protein: 19.4 grams—providing all essential amino acids
• Fiber: 5.4 grams—supporting digestive health
• Manganese: 1.53 mg—76% of the Daily Value (DV)
• Iron: 8.6 mg—48% DV
• Copper: 0.667 mg—74% DV
• Vitamin K: 23.1 mcg—substantial amount for bone health
• Magnesium: 115 mg—27% DV
• Calcium: 217 mg—17% DV
• Potassium: 729 mg—21% DV
• Zinc: 3.03 mg—28% DV

Beyond these essential nutrients, natto also contains vitamin B6, folate, vitamin C, selenium, and powerful antioxidants that protect your cells from oxidative damage.

7 Evidence-Based Health Benefits of Natto

1. Promotes Optimal Digestive Health

Natto is an excellent source of probiotics, containing billions of beneficial Bacillus subtilis bacteria per serving. These probiotics play a crucial role in maintaining a healthy gut microbiome, which is essential for proper digestion and nutrient absorption.

The fermentation process also breaks down complex compounds in soybeans that can be difficult to digest, including antinutrients like phytic acid and lectins. This makes the nutrients in natto more bioavailable and easier for your body to absorb compared to regular soybeans.

Research indicates that the probiotics in fermented foods can help reduce common digestive complaints such as bloating, gas, and constipation while promoting regular bowel movements and overall gut health.

2. Supports Cardiovascular Health

One of the most impressive benefits of natto is its potential to support heart health through multiple mechanisms. Natto contains nattokinase, a unique enzyme produced during fermentation that has been studied for its potential effects on cardiovascular wellness.

Nattokinase may help support healthy blood circulation and cardiovascular function. The fiber content in natto can also contribute to maintaining healthy cholesterol levels by binding to cholesterol in the digestive system.

Additionally, natto provides significant amounts of potassium, which plays a vital role in regulating blood pressure and supporting overall heart function. If you’re concerned about heart health, consult your healthcare provider about whether natto might be appropriate for your individual needs.

3. Strengthens Bone Density and Health

Natto is particularly beneficial for maintaining strong, healthy bones throughout your lifetime. It provides multiple bone-supporting nutrients, including calcium, magnesium, and vitamin K—all of which work synergistically to maintain bone mineral density.

The vitamin K in natto is especially important for bone health, as it plays a critical role in calcium metabolism and bone mineralization. Adequate vitamin K intake has been associated with better bone density and reduced risk of fractures, particularly in older adults.

The combination of calcium and vitamin K makes natto an excellent food choice for those looking to support skeletal health naturally through diet.

4. Boosts Immune System Function

Your immune system relies on a healthy gut microbiome to function optimally, and natto’s probiotic content directly supports this connection. The beneficial bacteria in natto help maintain the intestinal barrier, preventing harmful pathogens from entering your bloodstream.

Studies have shown that probiotic supplementation with Bacillus subtilis—the same strain found in natto—may reduce the incidence of respiratory infections and help the body recover more quickly from illness.

Furthermore, natto provides essential immune-supporting nutrients including zinc, iron, copper, selenium, and vitamin C, all of which play important roles in maintaining robust immune function and defending against pathogens.

5. May Support Weight Management

If you’re working on maintaining a healthy weight, natto can be a valuable addition to your diet. The high protein content helps promote satiety and reduce hunger between meals, potentially preventing overeating.

The fiber in natto also contributes to feelings of fullness and helps regulate blood sugar levels, preventing the spikes and crashes that can lead to cravings. Some research suggests that probiotic-rich foods may influence metabolism and body composition, though more studies are needed to fully understand these effects.

At just 211 calories per 100-gram serving, natto provides substantial nutrition without excessive calories, making it an excellent choice for those mindful of their caloric intake.

6. Contains Powerful Antioxidants

Natto contains various antioxidant compounds that help protect your cells from oxidative stress and free radical damage. This includes isoflavones—plant compounds found in soy products that have been studied for their potential health-promoting properties.

The fermentation process actually increases the bioavailability of these antioxidants, making them more easily absorbed and utilized by your body compared to non-fermented soy products.

Antioxidants play a crucial role in reducing cellular damage associated with aging and various health concerns, making natto a valuable addition to an antioxidant-rich diet.

7. May Support Brain Health and Cognitive Function

Emerging research suggests that natto may benefit brain health through multiple pathways. The vitamin K content in natto has been linked to cognitive function and brain health, while the probiotics may influence brain function through the gut-brain axis.

Additionally, natto provides nutrients essential for neurotransmitter production and nervous system function, including B vitamins, magnesium, and zinc. While more research is needed specifically on natto and cognitive health, the nutrient profile suggests potential benefits for brain function.

Potential Considerations and Who Should Be Cautious

While natto is safe and beneficial for most people, certain individuals should exercise caution or consult their healthcare provider before adding it to their diet.

Blood Thinning Medications: Natto contains vitamin K, which plays a role in blood clotting. If you’re taking anticoagulant medications, speak with your doctor before consuming natto regularly, as it may interact with your medication.

Thyroid Conditions: Soybeans contain compounds called goitrogens that may interfere with thyroid function in susceptible individuals. If you have thyroid issues, consult your healthcare provider about appropriate natto consumption.

Soy Allergies: Since natto is made from soybeans, individuals with soy allergies should avoid it completely.

Pregnancy and Breastfeeding: While natto is generally considered safe during pregnancy and breastfeeding, it’s always wise to discuss dietary changes with your healthcare provider.

How to Incorporate Natto Into Your Diet

If you’re new to natto, the unique texture and strong flavor can be challenging at first. Here are some tips to help you enjoy this nutritious food:

Start Small: Begin with a tablespoon mixed into other foods rather than eating it plain. Gradually increase the amount as you become accustomed to the flavor.

Add Flavorings: Traditional accompaniments like soy sauce, mustard, green onions, and sesame oil can help mask the strong flavor while you develop a taste for natto.

Mix with Rice: Serving natto over warm rice is the most common preparation method in Japan and helps balance the texture and flavor.

Try Different Preparations: Some people find that mixing natto with kimchi, avocado, or incorporating it into omelets makes it more palatable.

Make it at Home: While natto is available in many Asian supermarkets and online, you can also make it at home using soybeans and a natto starter culture, which allows you to control the fermentation time and intensity of flavor.

How Much Natto Should You Eat?

In Japan, a typical serving of natto is approximately 40-50 grams (about 1.5-2 ounces), usually consumed daily or several times per week. Starting with smaller amounts and gradually increasing to one serving per day is a reasonable approach for most people.

As with any food, moderation is key. While natto is highly nutritious, it should be part of a varied, balanced diet that includes a wide range of whole foods.

Natto vs. Other Fermented Soy Products

While tempeh, miso, and other fermented soy products offer health benefits, natto is unique in several ways:

Nattokinase Content: Only natto contains significant amounts of nattokinase, the enzyme with potential cardiovascular benefits.

Vitamin K Levels: Natto provides substantially more vitamin K than other fermented soy products.

Probiotic Strain: The Bacillus subtilis bacteria in natto is particularly hardy and more likely to survive digestion compared to some other probiotic strains.

Nutrient Density: The specific fermentation process for natto maximizes nutrient bioavailability in unique ways.

Scientific Research on Natto Benefits

The health benefits of natto are supported by a growing body of scientific research. Studies have examined natto’s effects on various aspects of health, from cardiovascular function to immune response.

Research on nattokinase has been particularly promising, with studies investigating its potential role in supporting healthy circulation. However, it’s important to note that while the research is encouraging, more large-scale human studies are needed to fully understand all of natto’s health effects.

The probiotic content of natto has also been well-studied, with research confirming that Bacillus subtilis can survive stomach acid and successfully colonize the intestines, providing ongoing digestive and immune benefits.

Where to Buy Quality Natto

Natto is becoming increasingly available outside of Japan as awareness of its health benefits grows. You can typically find it in:

• Asian supermarkets, particularly Japanese grocery stores
• Natural food stores and health food shops
• Online retailers specializing in Japanese foods
• Some mainstream supermarkets with international sections

When purchasing natto, look for products with minimal ingredients—ideally just soybeans and the bacterial culture. Avoid varieties with excessive added sugars or artificial ingredients. Natto is typically sold frozen or refrigerated in small containers.

The Bottom Line

Natto is an extraordinarily nutritious fermented food with impressive health benefits backed by scientific research. From supporting digestive and immune health to promoting cardiovascular wellness and strong bones, this traditional Japanese superfood offers numerous reasons to overcome any initial hesitation about its unique characteristics.

While the texture and aroma may take some getting used to, the potential health benefits make natto well worth trying. Start with small amounts, experiment with different preparations, and give yourself time to develop a taste for this remarkable food.

If you’re interested in incorporating natto into your diet but have specific health concerns or take medications, consult with your healthcare provider or a registered dietitian to ensure it’s appropriate for your individual circumstances.

Whether you’re looking to support your heart health, strengthen your immune system, or simply add more nutrient-dense fermented foods to your diet, natto is a powerful superfood that deserves consideration as part of a healthy, balanced eating pattern.

Sources:

• USDA FoodData Central – Natto Nutritional Information
• National Institutes of Health – Bacillus subtilis in Fermented Foods
• National Institutes of Health – Health Benefits of Natto
• PubMed – Probiotics and Digestive Health
• National Institutes of Health – Antinutrients in Soybeans
• National Institutes of Health – Fiber and Cardiovascular Health
• National Institutes of Health – Nattokinase Research
• National Institutes of Health – Probiotics and Immune Function
• PubMed – Probiotics and Infection Prevention
• National Institutes of Health – Bacillus subtilis and Respiratory Health
• NIH Office of Dietary Supplements – Calcium Fact Sheet
• PubMed – Nutrients and Immune Function