The Smell Test: Peanut Butter and Alzheimer’s
New research suggests peanut butter as innovative diagnostic tool.
Imagine: you wake up one day to find you can no longer enjoy the scent of peanut butter. Now imagine this: you wake up two years later to find you can no longer remember your spouse’s name. Could the first unfortunate scenario be a pre-cursor to the devastating memory loss of the second? Emerging research from the University of Florida suggests so.
While loss of smell has long been associated with Alzheimer’s disease (AD), this relationship has been, to date, underutilized in developing diagnostic tools. A new study from the University of Florida expounds upon this relationship and researchers believe they have, with the help of peanut butter, developed a brief olfactory test for AD.
The study, performed by graduate student Jennifer Stamps and her advisor Kenneth Heilman, tested the odor detection abilities of 94 participants; 18 with probable AD, 24 with mild cognitive impairment, 26 with other causes of dementia, and 26 matched controls.
The test itself was extremely simple: a container of peanut butter was held 30 cm beneath participants’ noses and moved up 1cm at a time. Participants – whose eyes were closed – were asked to indicate when they detected an odor of peanut butter, at which time the distance between the subject’s nostril and container was measured. Participants were tested one nostril at a time.
The choice to test participants one nostril at a time is key as AD patients often experience quicker olfactory degradation on the left side than the right. Portions of the olfactory cortex are often the initial sites of AD pathology, and the olfactory epithelium projects mainly to the left hemisphere of the brain – thus the asymmetrical loss of smell.
The study results reflected this asymmetry, with all 18 probable AD patients recording a more severe decrease in smell sensitivity on their left side. Furthermore, the probable AD patients demonstrated significantly more asymmetry than any of the other groups.
The test is currently only able to confirm diagnosis, and further research is needed to validate the approach. If future research is supportive, the study may lead to a non-invasive and inexpensive screening method for AD.
