Could Nattokinase Be Useful In Preventing Alzheimer’s Dementia?

🎧 Listen to This Article

Introduction

Alzheimer’s disease (AD) is one of the most feared illnesses of aging. It slowly steals memory, thinking ability, and even personality, leaving families struggling to care for loved ones who no longer recognize them. Despite decades of research, there is still no cure. Treatments exist, but they mostly slow down symptoms rather than stop the disease.

That’s why scientists are racing to find early warning signs—changes in the body that happen before full-blown Alzheimer’s develops. If doctors can catch the disease earlier, there’s a better chance of preventing or delaying its progression.

And here’s the surprising part: new research suggests that the nose may play a critical role in the early stages of Alzheimer’s. Problems such as chronic sinus inflammation, loss of smell, and even nasal microbes may be linked to how the disease develops and progresses.

This article will guide you through the fascinating science of how nasal health connects to brain health, and why a humble soybean enzyme called nattokinase might one day be part of the solution.

---

Alzheimer’s Disease in a Nutshell

Before diving into noses, let’s quickly recap what Alzheimer’s is.

• What it is: A brain disorder marked by memory loss, confusion, and difficulty with daily tasks.
• Hallmarks: Abnormal protein buildup—beta-amyloid (Aβ) plaques and tau tangles—in brain tissue.
• Impact: About 55 million people worldwide live with dementia, with Alzheimer’s being the most common form.

The disease often begins silently, decades before symptoms show. Scientists believe that inflammation, protein buildup, and nerve cell damage gradually spread throughout the brain, ultimately affecting memory and behavior.

Now let’s connect the dots to the nose.

---

The Nose-Brain Connection

The nose isn’t just for smelling. It’s also a gateway to the brain. The olfactory bulb, the brain’s smell center, sits right above the nasal cavity. Tiny nerves pass directly from the nose into this area, bypassing much of the brain’s usual protection system (the blood-brain barrier).

This makes the nose both powerful and vulnerable.

Chronic Rhinosinusitis (CRS) and Dementia Risk

One condition drawing attention is chronic rhinosinusitis (CRS). This is long-term inflammation of the sinuses and nasal passages, lasting more than three months. Symptoms include:

• Stuffy nose
• Facial pain or pressure
• Headaches
• Loss of smell

Here’s where it gets interesting:

• Studies show people with CRS are at higher risk of cognitive decline and dementia.
• Treating CRS sometimes improves thinking and memory.

The theory is that ongoing nasal inflammation may send inflammatory signals to the brain, triggering changes that contribute to Alzheimer’s.

---

Microbes, Inflammation, and the Brain

The nose is home to a diverse community of bacteria and other microbes, collectively known as the nasal microbiome. When this delicate balance is disturbed (a state known as dysbiosis), it can fuel inflammation.

Inflammation is a well-known driver of Alzheimer’s. In fact:

• Chronic nasal inflammation could travel along olfactory nerves into the brain.
• Beta-amyloid deposits—the sticky proteins of Alzheimer’s—may even begin in olfactory neurons before spreading deeper into the brain.

Think of the nose as the “front door” through which harmful processes may sneak in, setting the stage for later brain damage.

---

The Role of the Locus Coeruleus

Another key piece of the puzzle is a small but powerful brainstem area called the Locus Coeruleus (LC).

• The LC produces noradrenaline (norepinephrine), a chemical that helps regulate alertness, mood, attention, and memory.
• Damage to the LC happens very early in Alzheimer’s—even before plaques form.
• Recent studies in mice have shown that LC nerve fibers to the olfactory bulb are lost early, leading to olfactory problems.

Loss of smell, or hyposmia, is one of the earliest non-memory symptoms of Alzheimer’s. In fact, approximately 85% of patients report changes in their sense of smell before cognitive decline becomes apparent.

Therefore, smell testing may someday become a quick, non-invasive screening tool for assessing Alzheimer’s risk.

---

Microglia: The Brain’s Janitors

The brain has immune cells called microglia, which act like janitors, cleaning up damaged or dying cells. But sometimes they go overboard.

In Alzheimer’s research:

• Microglia in the olfactory bulb were seen “eating” LC nerve fibers.
• This process is triggered by a chemical signal that labels these fibers as “trash.”
• When researchers blocked this microglial activity in mice, the nerves survived—and so did the animal’s sense of smell.

This finding raises exciting possibilities: controlling microglia could help protect the sense of smell and slow the progression of Alzheimer’s disease.

---

A Unifying Picture

Let’s put all the pieces together:

1. Nasal inflammation or infection → Creates a hostile environment in the nose.
2. Inflammation spreads to the brain → Through the olfactory bulb and nerves.
3. Microglia attack LC nerve fibers → Leading to early smell loss.
4. Smell problems foreshadow Alzheimer’s → A warning sign years before memory loss begins.

This sequence shows how a simple sinus issue could, over time, connect to one of the most devastating brain diseases.

---

Where Does Nattokinase Fit In?

Here’s a fascinating twist: research suggests that nattokinase (NK), a natural enzyme from fermented soybeans (a Japanese food called natto), may help with some nasal problems.

What Nattokinase Does

• Breaks down fibrin, a protein involved in blood clots and thick mucus.
• Shrinks nasal polyps, growths that block sinuses and worsen CRS.
• Reduces mucus thickness in CRS and asthma patients.

While nattokinase hasn’t been directly studied for Alzheimer’s, helping nasal health could reduce chronic inflammation—and possibly lighten the inflammatory burden on the brain.

It’s not a cure, but it’s an intriguing avenue worth exploring.

Best Naturals Nattokinase, 2000 FU, 100 Mg, 3rd party lab tested

If you take nattokinase, you will notice the nasal mucus breaking up into smaller pieces inside your nose. That’s due to the enzymes in the nattokinase breaking up the protein bonds in the mucus.

---

What This Means for You

While scientists work on therapies, here are some practical takeaways for everyday people:

1. Pay Attention to Your Nose and Sinuses

• Persistent congestion, sinus pain, or loss of smell shouldn’t be ignored.
• Treating CRS not only improves quality of life but may also protect brain health.

2. Smell Testing May Become a Tool

• Simple smell tests could one day serve as an early screening tool for Alzheimer’s disease.
• If you notice changes in your sense of smell, mention it to your doctor.

3. Reduce Inflammation

• Eat anti-inflammatory foods (vegetables, fruits, omega-3s).
• Avoid smoking, excessive alcohol, and pollutants.

4. Watch the Research on Nattokinase

• Already used as a supplement for circulation, NK may find a role in sinus care.
• Always consult your physician before trying new supplements.

---

Hope for the Future

The idea that the nose could be the starting point of Alzheimer’s is both surprising and hopeful. Why? Because the nose is easily examined and treated compared to deep brain structures.

• Early diagnosis: Smell tests and imaging of the olfactory bulb may catch Alzheimer’s earlier than memory tests.
• Targeted therapies: Reducing nasal inflammation or modulating microglia could protect the brain.
• Preventive strategies, such as supplements like nattokinase, improved sinus care, and a healthier nasal microbiome, may lower the long-term risk.

In short, your nose may be more than just a smell organ—it could be a frontline defense against dementia.

---

Conclusion

Alzheimer’s remains one of medicine’s most challenging problems. However, by examining the humble nose, scientists are uncovering new pathways that may explain how the disease begins—and how to prevent it.

Chronic sinus problems, inflammation, smell loss, and even microbial imbalances could all feed into brain degeneration. The discovery that enzymes like nattokinase can help sinus health adds another piece to the puzzle.

While more research is needed, one thing is clear: taking care of your nose might just help protect your brain.

As the saying goes: “Follow your nose.” In the fight against Alzheimer’s, it may lead us to answers we’ve been searching for all along.

Don’t Get Sick!

💡 Support This Work

Creating well-researched articles, maintaining this website, and keeping the information free takes time and resources.
If you found this article helpful, please consider donating to support the mission of empowering people to live healthier, longer lives, without relying on medications.

🙏 Every contribution, big or small, truly makes a difference. Thank you for your support!

Follow me on Facebook, Gab, Twitter (formerly known as X), and Telegram.

Related:

1. Nattokinase Degrades Amyloids and Prions
2. Natto: An application of the 80-20 Rule
3. Prostate and Vascular problems relieved with Nattokinase
4. Should you take nattokinase on an empty stomach?
5. How to stop bleeding if on nattokinase
6. Natto: An application of the 80-20 Rule
7. How I Made and Appreciate Natto
8. Insulin Resistance and Atherosclerosis and the Nattokinase Solution
9. Protective Effects of Nattokinase against Strokes
10. How to dose Nattokinase, Bromelain and NAC
11. High-Dose Nattokinase to Shrink Atherosclerosis and Lower Blood Lipids
12. Nattokinase is Nontoxic with a High Safety Margin
13. The Outstanding Vascular Effects and Dose of Nattokinase
14. Another Study shows Nattokinase can Destroy the S1 Spike Protein
15. Nattokinase Degrades the SARS-CoV-2 Spike Protein
16. Soy Foods Do Not Increase Breast Cancer Risk

References:

1. Meyer, C., Niedermeier, T., Feyen, P.L.C. et al. Early Locus Coeruleus noradrenergic axon loss drives olfactory dysfunction in Alzheimer’s disease. Nat Commun 16, 7338 (2025). https://doi.org/10.1038/s41467-025-62500-8. https://www.nature.com/articles/s41467-025-62500-8#Abs1
2. Harrass S, Yi C, Chen H. Chronic Rhinosinusitis and Alzheimer’s Disease-A Possible Role for the Nasal Microbiome in Causing Neurodegeneration in the Elderly. Int J Mol Sci. 2021 Oct 18;22(20):11207. doi: 10.3390/ijms222011207. PMID: 34681867; PMCID: PMC8541405. https://pmc.ncbi.nlm.nih.gov/articles/PMC8541405/
3. Takabayashi T, Imoto Y, Sakashita M, Kato Y, Tokunaga T, Yoshida K, Narita N, Ishizuka T, Fujieda S. Nattokinase, profibrinolytic enzyme, effectively shrinks the nasal polyp tissue and decreases viscosity of mucus. Allergol Int. 2017 Oct;66(4):594-602. doi: 10.1016/j.alit.2017.03.007. Epub 2017 Apr 4. PMID: 28389065. https://pubmed.ncbi.nlm.nih.gov/28389065/

Image credits:

• Olfactory nerve – By Patrick J. Lynch, medical illustrator. (labeled by was_a_bee) – File:Head_olfactory_nerve.jpg by Patrick J. Lynch, medical illustrator, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=37206430
• Locus ceruleus – By Diego69 – http://www.baillement.com/anatomie/systemes.html, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=9446628
• Natto- By User: Gleam – Own work by the original uploader, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=110873576

© 2018 – 2025 Asclepiades Medicine, LLC. All Rights Reserved
DrJesseSantiano.com does not provide medical advice, diagnosis, or treatment

As an Amazon Associate, I earn from qualifying purchases