A new study by researchers from the Mayo Clinic suggests that keeping mentally active can protect against the symptoms of Alzheimer's, it doesn't stave off Alzheimer's disease, the Washington Post reports.

The new study was published in Neurology, the journal of the American Academy of Neurologists.

For the study, the researchers studied longitudinal data from 393 participants between 70 and 89 years of age. Out of the total participants, three hundred and forty of the patients had normal cognition, and 53 had mild cognitive impairment.

They separated the participants into those who were highly educated (14 years or more of education) and those who were not. The participants were given weekly questionnaires about physical and mental activities. The participants were made to go through MRI and PET scans to look for biomarkers of Alzheimer's disease.

The researchers found that mental activity reduces cognitive decline for everyone. However, in people with the genetic marker APOe4, which has been linked to Alzheimer's disease, mental activity seems to actually inhibit the progression of the disease in the brain.

The study showed that in people without the APOe4 gene, higher levels of academic attainment or more physical and mental activity did not inhibit the slowdown of brain metabolism, reductions in the volume of the hippocampus and worsening of amyloid plaques.

However, the 28 percent of the group who carried the APOe4 gene fared better when they were better-educated and stayed physically and mentally active during midlife.

Highly educated participants with APOe4 developed amyloid plaques about five years later than their less educated counterparts.

"People seemed to be able to compensate for the genetic risk if they had higher education," Prashanthi Vemuri, the study's lead author said.

As for the factors that could speed or slow the trajectory of Alzheimer's, Vemuri admitted,

"There's not much you can do about the process. There's a misconception that if you're mentally or physically active, you can ward off Alzheimer's disease."

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