Natto’s Anti-Inflammatory Profile
Scientific research largely indicates that natto possesses anti-inflammatory properties, making it an unlikely cause of general inflammation for most people. The primary drivers of this effect are the beneficial compounds produced during the fermentation process by the bacterium Bacillus subtilis.
The Role of Probiotics and Nattokinase
Natto is an excellent source of probiotics, the beneficial bacteria that contribute to a healthy gut microbiome. A balanced gut flora is crucial for a robust immune system and for regulating inflammatory responses throughout the body. Bacillus subtilis specifically has been shown to have anti-inflammatory effects within the gut itself.
Another key compound is nattokinase, an enzyme unique to natto fermentation. Numerous studies, both in vitro and animal models, suggest nattokinase can directly modulate inflammatory pathways. This includes downregulating pro-inflammatory cytokines like TNF-α and IL-6, and inhibiting NF-κB activation, a central regulator of inflammation. This effect has been observed in various contexts, including vascular and neuroinflammation.
Soy Isoflavones and Other Antioxidants
Beyond fermentation byproducts, the soybeans themselves contribute anti-inflammatory benefits. Soy isoflavones found in natto may help reduce inflammation, particularly in cases related to hormonal changes. Additionally, natto is rich in antioxidants that help combat oxidative stress, another key contributor to chronic inflammation.
Potential Negative Reactions and Misconceptions
While natto is overwhelmingly anti-inflammatory, some people may experience negative side effects that can be misinterpreted as inflammation. These issues are typically caused by pre-existing conditions or sensitivities rather than natto itself being a pro-inflammatory food.
High Fiber Content and Digestive Discomfort
For individuals unaccustomed to high-fiber diets, introducing natto can cause temporary digestive upset. The high fiber content may lead to:
- Gas
- Bloating
- Abdominal discomfort
- Changes in bowel habits, such as diarrhea
Histamine Intolerance
As a fermented food, natto naturally contains biogenic amines, including histamine. While this is not an issue for most, those with histamine intolerance may experience adverse reactions after consumption. Symptoms can mimic an allergic response and may include hives, flushing, headaches, or digestive upset. This is a specific intolerance to histamine, not a general inflammatory reaction caused by natto.
Soy Allergy
For people with a soy allergy, natto consumption is dangerous and should be avoided. An allergic reaction is a distinct immune response and can cause inflammation, but it is not a property of the food itself. A rare form of delayed anaphylaxis linked to natto has also been documented, particularly in individuals with prior sensitization to jellyfish stings due to a shared allergen, poly-γ-glutamic acid (PGA).
Natto's Anti-inflammatory vs. Adverse Effects
| Feature | Anti-Inflammatory Effects (General Population) | Adverse Effects (Specific Sensitivities) |
|---|---|---|
| Mechanism | Beneficial bacteria (B. subtilis) promote gut health and modulate inflammatory pathways. Nattokinase and isoflavones act as anti-inflammatories. | Histamine intolerance triggers mast cells; soy allergy is an IgE-mediated response; high fiber causes digestive gas. |
| Impact on Health | Supports heart health, aids digestion, strengthens immune function, and reduces chronic inflammation. | Can cause digestive discomfort, headaches, skin reactions, or in rare cases, anaphylaxis for sensitive individuals. |
| Relevant Compounds | Probiotics, nattokinase, soy isoflavones, antioxidants. | Histamine, poly-γ-glutamic acid (PGA), soy protein, high fiber. |
| Prevalence | Observed in the majority of healthy individuals who consume natto regularly. | Occurs in a smaller subset of the population with specific pre-existing conditions. |
Conclusion
In summary, the notion that natto can cause inflammation is largely a misconception for the general population. The vast majority of evidence points to natto being a powerful anti-inflammatory superfood, rich in beneficial probiotics and the enzyme nattokinase. Its potential anti-inflammatory effects extend from gut health to cardiovascular and neurological systems. Negative reactions, such as gas and bloating, are typically related to its high fiber content or specific sensitivities like histamine intolerance or a soy allergy, rather than general inflammatory properties. As with any food, individuals with underlying health conditions or known allergies should exercise caution and consult a healthcare professional. For those seeking to reduce inflammation, incorporating natto into a balanced diet can be a highly effective strategy.
How to safely add natto to your diet
- Start slowly and in moderation: If you are new to high-fiber foods, begin with a small portion of natto to allow your digestive system to adjust and minimize initial gas and bloating.
- Observe how your body reacts: Pay attention to any unusual symptoms, especially if you have known food sensitivities or suspect histamine intolerance.
- Combine with other ingredients: Mixing natto with rice or other foods can help mitigate its strong flavor and adjust to its texture, making it more palatable.
- Consult a doctor if necessary: If you have a thyroid condition, take blood-thinning medications, or have a known soy allergy, speak with a healthcare provider before making natto a regular part of your diet.
- Consider a dietary trial: For those with histamine intolerance, a trial under medical supervision may be necessary to assess if natto is suitable.
Resources
To learn more about the research behind nattokinase and its therapeutic applications, consider reviewing this article: Nattokinase as a functional food ingredient: therapeutic applications and molecular mechanisms.
Natto and Inflammation: Beyond the Gut
Numerous studies point to natto's benefits beyond just digestive health. For instance, research has shown that nattokinase helps attenuate endothelial inflammation, a key factor in cardiovascular health, by inhibiting inflammatory pathways. Its ability to regulate the immune system is also well-documented, with probiotics helping to boost natural antibodies and ward off infections. These far-reaching effects on systemic inflammation are what solidify natto's status as a superfood.
