What is Natto?
Natto is a traditional Japanese food made from whole soybeans that have been fermented with the bacterium Bacillus subtilis natto. The fermentation process is responsible for the food's distinctive sticky, stringy texture and strong, pungent smell. While it may be an acquired taste for some, its unique properties are the source of its significant health-boosting potential. During fermentation, the bacteria break down the beans' components, creating new bioactive compounds like the enzyme nattokinase and a high concentration of Vitamin K2.
The Nutritional Powerhouse
A single serving of natto is dense with essential nutrients that are crucial for optimal health. It is a fantastic source of plant-based protein and dietary fiber, which aids digestion and promotes satiety. Furthermore, it provides substantial amounts of key minerals, including iron, manganese, magnesium, calcium, and potassium. The fermentation process not only enriches the nutritional value but also makes these nutrients more bioavailable, meaning the body can absorb and utilize them more efficiently.
Cardiovascular Health
One of the most notable benefits of eating natto is its positive impact on heart health, primarily due to the potent enzyme nattokinase.
The Nattokinase Advantage
Nattokinase is a fibrinolytic enzyme, meaning it can help dissolve fibrin, the protein that forms blood clots. This anti-clotting effect is believed to improve blood flow, reduce the risk of deep vein thrombosis, and help maintain healthy blood vessels. Research indicates that regular consumption of nattokinase can lead to a reduction in blood pressure in individuals with hypertension. By helping to keep the blood thin and free-flowing, nattokinase reduces the overall strain on the cardiovascular system.
Cholesterol and Arterial Health
Beyond its blood-thinning properties, natto's fiber and polyunsaturated fat content can help manage cholesterol levels by lowering LDL, or "bad," cholesterol. Additionally, the high concentration of Vitamin K2 in natto helps prevent the calcification of arteries. Vitamin K2 directs calcium towards the bones and teeth, preventing its harmful accumulation in soft tissues like artery walls. This dual action of clearing blood clots and maintaining supple arteries makes natto a powerful food for cardiovascular health.
Bone Health Support
Natto is arguably the best dietary source of Vitamin K2, a crucial nutrient for building and maintaining strong bones.
Vitamin K2 (MK-7) and Osteoporosis
Vitamin K2 activates osteocalcin, a protein that helps bind calcium to the bone matrix. Without adequate Vitamin K2, this process is inefficient, which can lead to weakened bones and an increased risk of fractures. Observational studies in Japan have shown a strong correlation between regular natto intake and higher bone mineral density, as well as a significantly lower risk of osteoporotic fractures in postmenopausal women. The MK-7 form of Vitamin K2 found in natto is particularly effective for bone health.
More Effective Than Calcium Alone
For individuals concerned about bone density, especially post-menopause, adding natto to the diet may be more impactful than simply increasing calcium intake. Vitamin K2 ensures that the calcium you consume is directed to the bones, where it is most needed, and not to your arteries. One study found that postmenopausal women who ate four or more packets of natto per week reduced bone mass loss in the thigh bone by 80%.
Digestive Health and Immunity
As a fermented food, natto is a potent source of probiotics that benefit the gut microbiome and, by extension, the immune system.
Probiotic Powerhouse
The living Bacillus subtilis bacteria in natto contribute to a balanced and diverse gut flora. A healthy gut microbiome is fundamental to overall health, playing a role in everything from nutrient absorption to immune defense. A balanced gut can help alleviate common digestive issues such as bloating and constipation. Furthermore, the fermentation process breaks down antinutrients naturally present in soybeans, making natto easier to digest than unfermented soy products.
Immune System Boost
The beneficial bacteria in natto produce compounds that enhance the immune response. By supporting a healthy gut, which is a major site of immune function, natto helps the body protect against harmful pathogens. Studies have also suggested that the Bacillus subtilis probiotic strain may help reduce the risk of respiratory infections.
Natto vs. Other Fermented Soy Products
While other fermented soy products offer health benefits, natto's specific fermentation process creates a unique nutritional profile, particularly with its high levels of Vitamin K2 and nattokinase.
| Feature | Natto | Miso | Tempeh |
|---|---|---|---|
| Key Enzyme | Nattokinase (fibrinolytic) | Multiple enzymes from mold | Proteases from mold |
| Vitamin K2 (MK-7) | Exceptionally high concentration | Present, but in lower amounts | Present, but in lower amounts |
| Probiotic Strain | Bacillus subtilis natto (spore-forming) | Aspergillus oryzae (mold) and yeasts | Rhizopus oligosporus (mold) |
| Texture | Sticky, stringy, viscous | Paste-like | Firm, bean-like cake |
| Consistency | Strong aroma, earthy taste | Salty, savory umami | Mild, nutty, mushroom-like |
Conclusion: Incorporating Natto for Health
Eating natto regularly offers a powerful, natural way to support several aspects of your health, from cardiovascular function and bone strength to digestive wellness and immune defense. The unique combination of nattokinase and the high bioavailability of Vitamin K2 and probiotics makes this traditional food a true superfood. Whether you embrace its unique texture and flavor or opt for milder forms, the benefits are clear. While it is generally safe, those on blood thinners like warfarin should consult a healthcare provider due to the high Vitamin K content, which influences blood clotting. For everyone else, adding natto to your diet is a compelling strategy for enhancing long-term health and vitality. To explore one of the many studies that support these claims, see the research on nattokinase and its cardiovascular effects.
