The microbiome–nose–brain axis in health and disease
/ScienceDirect/2026
Why It Matters
This paper caught my attention because we've all heard about the gut-brain axis, but most people don't realize your nose has its own microbiome that sits millimeters from your brain. Understanding this connection matters if you're thinking about sinus health, chronic inflammation, or even cognitive function — though I'll be honest, the actionable interventions here are still theoretical.
Key Findings
- The nasal cavity hosts a distinct microbial ecosystem that sits in direct anatomical proximity to the brain via the olfactory nerve and cribriform plate
- Nasal microbes can influence neuroinflammation, neurodevelopment, and potentially neurodegenerative processes through production of metabolites and immune signaling
- Disruptions to nasal microbiome composition (dysbiosis) have been associated with conditions like Alzheimer's disease, Parkinson's disease, and chronic rhinosinusitis
- The olfactory system provides a unique route for microbial metabolites and immune signals to bypass the blood-brain barrier
- Current evidence is largely mechanistic and correlational — direct causal relationships between specific nasal microbes and brain outcomes remain to be established in humans