Our sense of smell does more than help us enjoy food or notice danger, like smoke from a fire. New research suggests it may also provide early warning signs of serious brain diseases like Alzheimer’s.
Scientists from the University of Chicago Medicine have found that people who lose their sense of smell over time may be more likely to experience memory loss and other changes in the brain linked to Alzheimer’s disease and dementia. Their study was published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.
Alzheimer’s disease affects over 6 million people in the United States. It is a condition that causes memory problems, confusion, changes in mood, and difficulty with everyday tasks. It often develops slowly, and many people are not diagnosed until the disease has already progressed.
That’s why finding early warning signs is so important—early detection may help patients get support sooner and manage the disease more effectively.
To understand how smell might be connected to brain health, the researchers used data from a long-term project called the Memory and Aging Project (MAP). In this study, older adults were tested once a year on several things: how well they could identify different smells, how well they were thinking and remembering, and whether they showed signs of dementia.
The scientists noticed something interesting: people who had a faster decline in their ability to smell—while their thinking and memory were still normal—were more likely to show early signs of Alzheimer’s later on.
These signs included a smaller amount of gray matter (the brain tissue involved in smell and memory), worse performance on memory tests, and a higher chance of developing dementia.
In fact, the risk of dementia from losing the sense of smell was similar to the risk found in people with the APOE-e4 gene, which is one of the strongest known genetic risk factors for Alzheimer’s disease.
This suggests that a simple smell test could help doctors spot people who are at higher risk, long before obvious memory problems appear. It could be a helpful tool alongside other tests to monitor brain health as people age.
The research team plans to keep studying this connection. They want to examine brain tissue more closely to see how changes in smell are linked to the physical signs of Alzheimer’s in the brain. They also want to include a more diverse group of participants in future studies to make sure the findings apply to everyone.
This isn’t the first time scientists have looked at smell and aging. In earlier research, the same team found that older adults who had completely lost their sense of smell were three times more likely to die within five years. In that study, loss of smell was an even stronger predictor of death than serious conditions like lung disease, heart failure, or cancer.
These findings show that the sense of smell is more important than many people realize. It may offer a window into how the brain is aging and whether someone is at risk for diseases like Alzheimer’s.
If you’re interested in protecting your brain health, other studies suggest that eating a Mediterranean-style diet and taking blueberry supplements may help slow cognitive decline. There’s also evidence that vitamin D deficiency and nighttime blood pressure problems could raise the risk of Alzheimer’s or other forms of dementia.
While more research is needed, this study gives hope that something as simple as a smell test could one day help us detect Alzheimer’s earlier—and take steps to fight it sooner.
If you care about brain health, please read studies about vitamin D deficiency linked to Alzheimer’s and vascular dementia, and higher magnesium intake could help benefit brain health.
For more information about brain health, please see recent studies about antioxidants that could help reduce dementia risk, and coconut oil could help improve cognitive function in Alzheimer’s.
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