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Why A Loss of Smell Stinks and May Be A Warning Sign of Dementia

Sense of smell

Researchers have found in a new study that the inability to smell peppermint and other familiar smells may be a link to the disease. The World Health Organization (WHO) has estimated that the rate of dementia is set to triple by 2050 from 50 million to 152 million. Alzheimer’s disease is the most common form of dementia. Can our nose give our brain away?


An experiment recently published in the Journal of the American Geriatrics Society reveals that our sense of smell is connected to the disease we know as dementia. Researchers from the University of Chicago Medical Center conducted an experiment involving 3,000 people, ages 57 to 85, in which their ability to recognize 5 different scents was tested. The 5 scents were: peppermint, fish, orange, rose, and leather.

The statistics were as follows: 78% of subjects correctly identified at least 4 out of the 5 scents, 14% could recognize 3 out of 5, 5% could recognize 2 scents, 2% could make out one, and 1% couldn’t determine one out of the five.

Diagnosed with Dementia

After 5 years passed, they tracked down each participant. Almost all of the participants that had been unable to identify any had been diagnosed with dementia, and 80% of those who had only been able to recognize one or two of the 5 scents were also dementia patients.

The study’s lead author, Jayant M. Pinto, said in a statement concerning the experiment: "These results show that the sense of smell is closely connected with brain function and health. We think smell ability specifically, but also sensory function more broadly, may be an important early sign, marking people at greater risk for dementia.”

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Pinto clarified that the study is far from being a clinical test. "Our test simply marks someone for closer attention. Much more work would need to be done to make it a clinical test. But it could help find people who are at risk. Then we could enroll them in early-stage prevention trials.”

The study, "Olfactory Dysfunction Predicts Subsequent Dementia in Older US Adults”, was published in early September of 2017. It followed a paper published in 2014 which addressed the increased risk of death associated with olfactory dysfunction.

Olfactory Nerve

It is interesting to note that the olfactory nerve is the only cranial nerve directly exposed to the environment. The study’s co-author, Maria K. McClintock, PhD, the David Lee Shillinglaw Distinguished Service Professor of Psychology at the University of Chicago, noted: “A decrease in the ability to smell may signal a decrease in the brain’s ability to rebuild key components that are declining with age, leading to the pathological changes of many different dementias.”

This is significant because the olfactory system also has stem cells which self-generate. Both studies were funded by the National Institutes of Health.

As the national rate of dementia increases at an alarming rate, we must be proactive in identifying red flags in our health and in the health of loved ones. Your nose may play an important part in this, but further research will continue to show just how significant a role olfactory dysfunction plays in the prevention of dementia.

Check out these other great articles by EMaxHealth: Daughter’s Beautiful Tribute to Father’s Last Moments with Dementia, Why BDNF Decreases Your Risk of Alzheimer’s According to Science, and This Popular Vegan Practice Can Help You Dodge Alzheimer’s Disease.