An Introduction to Japan's Fermented Superfood
For centuries, natto has been a celebrated staple of the Japanese diet, typically enjoyed at breakfast with rice. While its unique, sticky texture and pungent aroma can be an acquired taste for some, its impressive nutritional profile and potent health benefits are anything but polarizing. Created by fermenting boiled soybeans with the bacteria Bacillus subtilis, natto's unique qualities are a direct result of this process, which supercharges its health-promoting properties. As research uncovers more about this fermented delicacy, its status as a superfood is only further solidified.
What is Natto?
Natto is a traditional Japanese food made by boiling whole soybeans and fermenting them with Bacillus subtilis bacteria. This fermentation process transforms the beans, resulting in the signature sticky, stringy, and slimy texture often compared to melted cheese. The fermentation is also responsible for natto's distinct, powerful aroma and rich, umami flavor. The end product is packed with nutrients that are more bioavailable than in unfermented soybeans because the process breaks down anti-nutrients.
The Health Benefits of Natto on Your Body
The effects of natto on the human body are extensive, largely due to its unique combination of probiotics, enzymes, and vitamins.
Gut Health and Improved Digestion
Natto is a potent source of probiotics, particularly the spore-based Bacillus subtilis. This probiotic strain is notably resilient, surviving the harsh acids of the stomach to reach the intestines and colonize the gut. The benefits to the gastrointestinal system are significant:
- Balanced Microbiota: The probiotics help balance gut bacteria, which is important for overall digestive health and may help with conditions like irritable bowel syndrome (IBS).
- Enhanced Digestion: Bacillus subtilis helps break down complex carbohydrates and proteins, aiding digestion and potentially reducing gas and bloating.
- Prebiotic Effects: Natto also contains prebiotic dietary fiber, which feeds the beneficial bacteria in your gut, supporting their growth and function.
Cardiovascular Health with Nattokinase
One of the most well-researched compounds in natto is nattokinase, a powerful enzyme produced during the fermentation process. Its effects on heart health are a major reason for natto's superfood status.
- Natural Blood Thinner: Nattokinase functions as a natural fibrinolytic agent, meaning it can dissolve fibrin, the protein that forms blood clots. This mechanism helps improve blood flow and can significantly reduce the risk of cardiovascular events like strokes and heart attacks.
- Lowered Blood Pressure: Studies have indicated that regular nattokinase intake can lead to reduced systolic and diastolic blood pressure. This occurs by reducing blood viscosity and improving overall circulation.
Stronger Bones from Vitamin K2
Natto is arguably the richest dietary source of Vitamin K2, specifically the MK-7 isoform. This fat-soluble vitamin plays a critical role in bone metabolism.
- Calcium Distribution: Vitamin K2 activates proteins that guide calcium to where it is needed most—your bones—and directs it away from areas where it could be harmful, like arteries and soft tissues.
- Reduced Fracture Risk: Multiple studies have shown a strong link between regular natto consumption and improved bone mineral density, particularly in postmenopausal women, significantly reducing the risk of osteoporosis-related fractures.
Additional Systemic Benefits
Beyond its core impacts, natto contributes to overall wellness in several other ways:
- Immune System Support: The combination of probiotics and essential nutrients like Vitamin C, zinc, and iron help bolster the immune system by promoting a healthy gut microbiome, which is a key player in immune function.
- Antioxidant and Anti-inflammatory Effects: Natto contains antioxidants that protect cells from damage. The anti-inflammatory properties of nattokinase and other compounds can help reduce chronic inflammation in the digestive tract and elsewhere.
- Weight Management: Natto's high protein and fiber content promote satiety, helping to manage appetite and support healthy weight.
Natto vs. Nattokinase Supplements: A Comparison
For those who cannot tolerate natto's taste or texture, nattokinase supplements offer an alternative. However, there are notable differences.
| Feature | Whole Food Natto | Nattokinase Supplements |
|---|---|---|
| Nutrient Profile | Rich in protein, fiber, iron, calcium, Vitamin C, Vitamin K2 (MK-7), and probiotics. | Isolates the nattokinase enzyme, often without the additional nutrients or probiotics found in the whole food. |
| Synergy | The nutrients and compounds, like nattokinase and Vitamin K2, work synergistically in the body for maximum effect. | Provides a concentrated dose of one component, which may not be as effective as the synergistic effect of the whole food. |
| Bioavailability | The fermentation process increases the bioavailability of many nutrients, making them easier to absorb. | Nattokinase capsules are often designed to be acid-resistant to ensure the enzyme survives digestion. |
| Taste & Experience | Offers the full food experience, though its unique taste and slimy texture are major hurdles for many. | Tasteless and convenient for those who dislike the food itself. |
| Vitamin K2 Content | Exceptionally high, naturally occurring Vitamin K2 (MK-7). | Some products exclude Vitamin K2, which is important for individuals on blood thinners. |
Potential Risks and Precautions
While natto is generally safe, certain individuals should exercise caution or avoid it entirely.
- Medication Interactions: Individuals on blood-thinning medications, such as warfarin, must consult a doctor before consuming natto or nattokinase supplements. Natto's high Vitamin K2 content can interfere with these drugs. Nattokinase also has blood-thinning properties.
- Soy Allergies: As it is made from soybeans, natto should be avoided by those with soy allergies or intolerances.
- Thyroid Function: Soybeans are considered goitrogenic, meaning they can potentially interfere with thyroid function in high amounts, especially for those with existing thyroid issues. Cooking and fermentation may reduce this effect, but those with hypothyroidism should limit intake.
- Before Surgery: Given its blood-thinning effects, it is recommended to stop consuming natto or nattokinase supplements at least two weeks before any scheduled surgery.
Conclusion
From a potent boost to digestive health to its powerful effects on the cardiovascular and skeletal systems, what natto does to your body is largely positive and far-reaching. Its status as a nutrient-dense superfood, particularly for its nattokinase and Vitamin K2 content, is well-earned. While its distinct characteristics are not for everyone, incorporating it into your diet, or considering nattokinase supplements, can offer significant health advantages. As with any dietary change, especially if you have pre-existing health conditions or take medication, it is wise to consult a healthcare provider to ensure it is right for you. [Healthline provides further details on natto's nutritional profile(https://www.healthline.com/nutrition/natto)].
