Natto: A Japanese Superfood Explained
Natto is a traditional Japanese food made by fermenting soybeans with a unique bacterium, Bacillus subtilis var. natto. Known for its sticky, stringy texture and pungent aroma, it is often served with rice, soy sauce, and karashi mustard. While its distinctive characteristics can be polarizing, its exceptional nutritional profile has earned it a reputation as a powerful superfood with a wide range of health benefits. The fermentation process unlocks a higher concentration of nutrients and produces bioactive compounds not present in unfermented soybeans.
A Probiotic Powerhouse for Gut Health
One of the most significant advantages of natto is its rich probiotic content, specifically the potent spore-based probiotic Bacillus subtilis. Unlike many other probiotics that may be destroyed by stomach acid, these spores are highly resilient and can reach the intestines intact, where they contribute to a healthier gut microbiome.
How Natto Supports a Healthy Gut
- Enhances Gut Flora: The active bacteria in natto help to increase the number and diversity of beneficial microbes in your gut, which is essential for overall digestive wellness.
- Improves Digestion: By promoting a balanced gut flora, natto can help alleviate common gastrointestinal issues such as constipation, gas, and bloating.
- Supports Nutrient Absorption: A healthy gut environment is more efficient at breaking down and absorbing nutrients from food. The fermentation process itself also breaks down antinutrients in soybeans, making them more digestible.
- Boosts Immunity: A large portion of the body's immune system resides in the gut. By supporting the health of the gut microbiome, natto helps fortify the immune system against pathogens.
Strengthening Bones with Vitamin K2
Natto is arguably the richest food source of Vitamin K2 (specifically menaquinone-7 or MK-7), providing hundreds of micrograms in a single serving. Vitamin K2 plays a critical role in bone health by activating proteins that direct calcium to the bones and teeth, preventing it from depositing in arteries and soft tissues.
Clinical studies from Japan have provided compelling evidence of natto's bone-strengthening effects:
- Habitual natto intake has been associated with reduced age-related bone mineral density loss in postmenopausal women.
- Regular consumption has been linked to a significantly lower risk of osteoporotic fractures.
- The effect is considered dose-dependent, with more frequent consumption yielding greater benefits.
Cardiovascular Support from Nattokinase
During fermentation, Bacillus subtilis produces a potent enzyme called nattokinase, which is highly beneficial for cardiovascular health. Nattokinase is known for its fibrinolytic activity, meaning it can help break down blood clots and prevent new ones from forming.
The Heart-Healthy Actions of Nattokinase
- Dissolves Blood Clots: Nattokinase is a natural blood thinner that helps improve blood flow and can potentially reduce the risk of heart attack and stroke.
- Lowers Blood Pressure: Some studies suggest that nattokinase may help lower blood pressure, which is a major risk factor for heart disease.
- Reduces Cholesterol: The fiber and polyunsaturated fats found in natto also contribute to lowering LDL ('bad') cholesterol levels.
A Nutrient-Dense Addition to Your Diet
Beyond its unique enzymes and probiotics, natto is a highly nutritious food, offering substantial amounts of protein, fiber, and essential minerals.
Nutritional Information per 50-gram serving (Approximate)
- Calories: ~110 kcal
- Protein: ~9.7 g
- Fat: ~5.5 g (mostly polyunsaturated)
- Fiber: ~2.7 g
- Vitamin K (mostly K2): >100% DV
- Manganese: >30% DV
- Iron: >20% DV
- Other Nutrients: Contains significant amounts of calcium, magnesium, potassium, and zinc.
Comparison: Natto vs. Other Fermented Foods
| Feature | Natto | Kimchi | Yogurt | Sauerkraut |
|---|---|---|---|---|
| Primary Fermenting Agent | Bacillus subtilis var. natto | Lactobacillus species | Lactobacillus and Streptococcus species | Lactobacillus species |
| Best Known For | Vitamin K2 (MK-7), Nattokinase | Probiotics, Vitamin C | Probiotics, Calcium | Probiotics, Fiber |
| Vitamin K2 (MK-7) Level | Highest food source (rich) | Very low | Varies by source (some cheeses high) | Low |
| Primary Health Benefit | Bone & Heart Health | Digestive & Immune Health | Digestive & Bone Health | Digestive Health |
| Protein Content | High | Low | Moderate | Low |
| Notable Characteristic | Sticky, stringy texture & pungent smell | Spicy, sour flavor | Creamy texture | Sour, tangy flavor |
How to Eat Natto for Maximum Benefit
While the strong taste and texture can be challenging for newcomers, here are some ways to incorporate natto into your diet:
- Traditional Breakfast: Mix natto with the included tare sauce and mustard, and serve over a bowl of hot steamed rice.
- Modern Pairings: Combine it with avocado, add it to toast, or sprinkle natto powder over salads.
- Creative Dishes: Incorporate it into miso soup or an omelet for a nutritional boost.
- Adjusting to the Taste: Start with small portions and add toppings like green onions or kimchi to balance the flavor. Low-odor versions are also available for those sensitive to the smell.
Important Considerations and Who Should Avoid Natto
Though highly nutritious, natto is not for everyone. Individuals with a soy allergy should avoid it. Furthermore, due to the high Vitamin K content and nattokinase, people taking blood-thinning medications like warfarin should consult their doctor before adding natto to their diet, as it may interfere with the drug's effects.
Conclusion
From strengthening bones and supporting a healthy heart to promoting a thriving gut microbiome, the health benefits of Japanese natto are extensive and well-documented. Its unique fermentation process creates a nutritional profile that is rich in probiotics, highly bioavailable Vitamin K2, and the potent enzyme nattokinase. While it may require an adjustment period to appreciate its distinctive characteristics, incorporating natto into your diet can be a valuable step towards better long-term health and wellness. For those seeking to boost their bone, heart, and gut health with a nutrient-dense food, natto offers a powerful, traditional solution.
For more detailed scientific studies and information on the properties of nattokinase, you can visit PubMed.
