The Pros: The Impressive Health Benefits of Natto
Natto, a traditional Japanese food made from fermented soybeans, is lauded as a superfood due to its dense nutritional profile and unique enzymatic properties. Its fermentation process, driven by the bacterium Bacillus subtilis, unlocks and enhances several key nutrients, making them more bioavailable and beneficial for the body.
Heart and Circulatory Health
Natto’s most celebrated benefit for cardiovascular health comes from nattokinase, a potent enzyme produced during fermentation.
- Natural Blood Thinner: Nattokinase has been shown to have fibrinolytic activity, meaning it can help dissolve blood clots, which is a major factor in preventing heart attacks and strokes.
- Blood Pressure Regulation: Multiple studies suggest that regular nattokinase intake can help lower blood pressure, reducing the overall strain on the cardiovascular system.
- Cholesterol Reduction: The fiber and plant protein in natto can contribute to lowering levels of LDL ("bad") cholesterol.
Stronger Bones with Vitamin K2
Natto is arguably the best dietary source of vitamin K2, specifically menaquinone-7 (MK-7), which plays a crucial role in bone metabolism and calcium regulation.
- Calcium Deposition: Vitamin K2 helps direct calcium into the bones and teeth, preventing its accumulation in the arteries where it can cause calcification and increase heart disease risk.
- Reduces Fracture Risk: Research indicates that adequate vitamin K2 intake can reduce the risk of bone fractures, especially in postmenopausal women.
Superior Gut Health and Digestion
As a fermented food, natto is a natural probiotic, supporting a healthy and diverse gut microbiome.
- Probiotic Boost: The beneficial bacteria in natto help balance the intestinal flora, improving digestion and potentially alleviating symptoms like gas, bloating, and constipation.
- Enhanced Nutrient Absorption: A healthy gut biome facilitated by probiotics is more efficient at absorbing nutrients from food.
High in Plant-Based Protein and Other Nutrients
Natto is a complete plant-based protein source, making it an excellent dietary addition for vegans, vegetarians, and anyone looking to increase their protein intake. It's also packed with other vital micronutrients.
- Protein and Fiber: Its high protein and fiber content promote satiety, aiding in weight management.
- Iron and Manganese: Natto is a good source of iron, which is essential for oxygen transport, and manganese, important for metabolism and antioxidant function.
The Cons: The Challenges and Risks of Natto
Despite its numerous health advantages, natto's unique characteristics and potent compounds present some significant challenges and risks that consumers should be aware of.
The Acquired Taste, Smell, and Texture
For many outside of Japan, natto’s most significant barrier to consumption is its sensory profile.
- Pungent Aroma: The distinct, powerful, and often pungent smell is frequently compared to aged cheese or ammonia, which can be off-putting.
- Slimy Texture: The notorious sticky, stringy, and slimy texture, known as neba-neba in Japanese, is the result of the fermentation process and is a major hurdle for many first-time tasters.
Potential Drug Interactions
The potent effects of nattokinase and high vitamin K2 content mean natto can interact negatively with certain medications.
- Blood Thinners: Individuals taking anticoagulant medications like warfarin must consult a doctor before consuming natto, as its high vitamin K2 content can interfere with the drug’s effectiveness. The nattokinase enzyme also has blood-thinning properties, increasing the risk of bleeding.
- Blood Pressure Medication: Since nattokinase can lower blood pressure, combining it with antihypertensive drugs could cause blood pressure to drop too low.
Allergic Reactions
As a soy-based product, natto poses a risk for those with soy allergies. While rare, a specific type of late-onset anaphylaxis has been linked to poly-gamma-glutamic acid (PGA), a component of the natto's sticky texture.
Risks for Immunocompromised Individuals
Fermented foods containing live bacteria are generally not recommended for those with severely compromised immune systems. Studies have shown that natto intake can be associated with Bacillus subtilis bacteremia in certain high-risk groups, such as children undergoing chemotherapy.
Comparing the Pros and Cons of Natto
| Feature | Pros | Cons |
|---|---|---|
| Cardiovascular | Nattokinase helps dissolve blood clots and lower blood pressure. | Potential drug interactions with blood thinners and blood pressure medication. |
| Bone Health | Excellent source of vitamin K2, promoting strong bones and proper calcium use. | High vitamin K2 content can interfere with warfarin. |
| Gut Health | Contains beneficial probiotics that aid digestion and boost the immune system. | Not recommended for severely immunocompromised individuals due to live bacteria. |
| Taste & Texture | Umami, rich flavor that is highly prized by fans. | Strong, pungent smell and slimy, sticky texture can be very off-putting for newcomers. |
| Nutritional Profile | A complete plant-based protein source, rich in fiber, iron, and manganese. | Can trigger allergic reactions in those with soy sensitivities. |
Ways to Mitigate the Challenges of Natto
For those interested in reaping the health benefits but intimidated by the challenges, there are several ways to make natto more palatable. Start with small amounts mixed into other foods, rather than eating it plain on rice. Adding stronger flavors can also help mask the pungency.
- Mix-ins: Incorporate bold ingredients like karashi (spicy mustard), soy sauce, chopped green onions, kimchi, or a raw egg yolk.
- Cooking: Heating natto, such as in fried rice or an omelet, can soften the texture and mellow the taste, though it may reduce some of the probiotic benefits.
- Blend It: For those who cannot tolerate the texture, blending natto into sauces, soups, or smoothies can be an effective way to consume it.
Conclusion
Natto is a nutritional powerhouse, offering substantial benefits for heart and bone health, as well as digestion, largely due to its high vitamin K2 content and probiotic properties. However, its pungent odor, slimy texture, and potential for serious drug interactions mean it's not a suitable food for everyone. Its divisive nature makes it a classic example of a superfood with an extremely high barrier to entry. For those who can acquire a taste for it, natto can be a valuable addition to a healthy diet. However, individuals on blood thinners or with compromised immune systems should approach it with caution and always consult a healthcare professional. For more details on the enzyme that provides many of natto's benefits, consult a reputable medical source on nattokinase.
