Most of what you've heard about brain health starts somewhere else. The gut. The microbiome. Sleep. Exercise. All of it real, all of it important. But there is a window into the brain that medicine has been quietly walking past for decades. The one in the middle of your face.
The olfactory system is the only one of our senses that bypasses the thalamus and runs directly into the regions of the brain we associate with memory, emotion, and meaning. When those structures begin to deteriorate, scent is one of the first things to go. Not always dramatically. Often quietly. A coffee that doesn't smell quite right. A familiar perfume that has lost its weight. A meal that isn't quite hitting.
This is what we mean when we say smell loss is a biomarker. The decline doesn't start in the memory. It starts at the nose.
Topics in this pillar
- Smell loss as an early biomarker for Alzheimer's disease
- Olfactory training and its effect on grey matter and verbal fluency
- The Proust phenomenon: why smell-triggered memory is different
- Sleep, memory consolidation, and the olfactory system
- Post-COVID smell loss and what we now know about recovery
- The chemosensory exam your doctor probably doesn't run (and how to ask for one)
- Olfactory health across the lifespan
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