How are Peanut Butter and Alzheimer’s Connected?

Studies show that your sense of smell could predict if you may be likely to develop Alzheimer’s disease

Because people are living longer, the number of Alzheimer’s disease cases is on the rise. The disease currently has no cure, but researchers are working to identify who may be susceptible to it. Then, they can identify possible treatments to prevent the progression of symptoms.

Screening for memory impairments, particularly with traditional tests, may not detect problems early enough. With the help of federally funded research, Dr. David Lowenstein at the University of Miami Health System’s Center on Aging has developed some potentially more important memory tests.

This is where peanut butter comes in.

It is known that the sense of smell, or olfaction, is compromised in people with Alzheimer’s disease. The amyloid protein can accumulate in the olfactory bulb, the part of the brain that houses the sense of smell. Changes in your sense of smell may be a predictive marker of Alzheimer’s.

Researchers are working on Alzheimer’s tests at the University of Florida, in collaboration with the University of Miami, thanks to funding from the McKnight Foundation. They have found that a tablespoon of peanut butter and a ruler may be a useful screening test for early Alzheimer’s. Peanut butter is a pure odorant, meaning that smelling peanut butter does not involve any other senses.

How the peanut butter tests work:

  • After the patient closes his eyes and mouth and blocks one of the nostrils, the doctor puts the ruler next to the open nostril as the patient breathes normally. The clinician moves the peanut butter in a small plastic cup up the ruler one centimeter at a time until the patient can detect the smell.
  • The distance is recorded and the same test is done with the other nostril.

The study showed a difference between the right and left nostrils’ ability to detect the odor for patients with early Alzheimer’s disease. In most cases, the left nostril was more impaired and did not detect the peanut butter until it was about 10 centimeters closer to the nose. However, this finding of a left versus right effect was not confirmed in a later study.

Researchers want to know if trying the test on patients with mild memory loss could be used to predict which of them will get Alzheimer’s disease.

Current drugs being used to treat Alzheimer’s don’t work well enough, says Dr. Philip Harvey, director of psychiatry at the University of Miami Health System. However, they may have more potential as prevention therapies if we could target people who don’t yet have the disease and get to them early enough to actually prevent it.

Another bonus: smell tests are inexpensive and can potentially be linked with changes in amyloid protein deposits.

“We could do a PET scan on everyone, checking for amyloid protein deposits, but those cost upwards of $3,000,” says Harvey. “Insurance won’t pay for them without other information.”

Harvey says we don’t yet know if changes in smell come before amyloid build-up or at the same time. If, he says, they can develop a reliable smell- or performance-based test that is coordinated with research with pre-Alzheimer’s, then a PET scan in those people would be justified and preventive treatment could be more fully evaluated.

Anyone with concerns about their memory or who has a family history of Alzheimer’s should contact us to discuss a memory assessment.

Read more health innovation news from the University of Miami Health System.

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