INHALING MENTHOL IMPROVES COGNITIVE FUNCTION in animal models of Alzheimer’s dementia. That’s the finding of a recent study in mouse models published in Frontiers in Immunology. Could we someday use smell to fight Alzheimer’s dementia?
Alzheimer’s is a degenerative brain disease and the most common dementia form. Dementia is not a specific disease. It’s an overarching term that describes a group of symptoms. The Alzheimer’s Association explains it this way:
Dementia is a general term for loss of memory, language, problem-solving, and other thinking abilities that are severe enough to interfere with daily life.
Worldwide, there are 55 million people are living with Alzheimer’s and other dementias. Alzheimer’s disease is the most common cause of dementia, representing up to 80 percent of cases.
The second most common dementia form is vascular dementia, which occurs because of microscopic bleeding and blood vessel blockage in the brain. Those with brain changes of multiple dementia types have mixed dementia.
Many other conditions can cause symptoms of dementia, including some that are reversible, such as thyroid problems and vitamin deficiencies.
Menthol Inhalation and Alzheimer’s in Mice
A recent research investigation shows that repetitive brief exposure to methanol impacts the immune system of mice with dementia. When the animals smell the substance, they do not experience cognitive decline.
The Pamplona (Spain) researchers discovered that the mice showed a drop in their interleukin-1-beta levels by smelling menthol. This protein is linked to an inflammatory response.
Next, the scientists blocked this protein with a drug used to treat autoimmune conditions. Doing so could boost the cognitive abilities of the mice with Alzheimer’ s-like symptoms.
Menthol Smell and Brain Inflammation
Menthol drops inflammation in the brain area associated with memory. The substance modulates the prefrontal cortex’s immune response, a memory input center. This brain part is dysfunctional in those with Alzheimer’s disease.
The researchers show that menthol inhalation reduces inflammatory chemicals (cytokines) in the mouse Alzheimer’s model (compared to a control group). Put more simply, smelling menthol lowers brain inflammation.
I am excited to hear this, as I think many chronic diseases (ranging from cancer to heart attack, from stroke to obesity and diabetes) have a central component of inflammation.
Smell and the Brain’s Limbic System
Our olfactory (smell) tracts are connected to the limbic system. The latter is linked to emotional and fight-or-flight responses, aggression, sexual response, and memory processing.
Moreover, the limbic: olfactory system connection is responsible for the close association of smell and memory. This link is known as the Proust effect.
Writing in Swann’s Way, Marcel Proust explained that the smell of a pastry he dipped in his tea brought on a rush of joy associated with his childhood.
For me, odors often stimulate memories. When I smell grapes in the wild, I travel back to my childhood walking in my grandparents’ yard, one with grapes crawling along many vines on a fence. Freshly cut grass takes me back to my childhood in Stratford, Connecticut (USA), running through parks (and neighbors’ yards).
For me, smells conjure up memories, often childhood ones. Do they for you?
Key points — Could We Someday Inhale Menthol to Fight Alzheimer’s Dementia?
Question. Could we someday inhale menthol (or other substances) to fight Alzheimer’s dementia?
Findings. This mouse study illustrates how we may someday use the olfactory pathways to modulate our brains.
Meaning. How do smells get to the brain? After entering the nose and passing through the olfactory bulb, smell info goes to the brain’s hippocampus and amygdala. These brain areas are involved in learning, emotion, and memory.
Of course, the current study involves mice, not humans. We have much to do, but I am excited that scientists are considering exploiting the smell: brain connection. No invasive implanted deep brain stimulators.
Now, I am off to smell some sweet potato pie and revisit childhood memories from Georgian (USA) summers.
If you know someone with colorectal cancer, here is my book on the subject:
Dr. Michael Hunter’s Colon and Rectal Cancer Book.
Dr. Michael Hunter’s Colon and Rectal Cancer Book is a must-have resource for colon or rectal cancer patients. www.amazon.com.
The information I provided in this blog is for educational purposes only and does not substitute for professional medical advice. Please consult a medical professional or healthcare provider for medical advice, diagnoses, or treatment. I am not liable for risks or issues associated with using or acting upon the information in this blog.
Thank you for reading “Smell to Fight Dementia?”
