Protecting Yourself Against Alzheimer’s Disease

I have a keen interest in healthy aging, and we have talked before about some of the strategies that can help protect you against developing cognitive decline.

New research now shows for the first time that, of all lifelong activities, only a high level of mental or cognitive activity protects against the devastating memory loss of Alzheimer’s disease. High levels of social or physical activity are not enough.

Researchers from the Byrd Alzheimer’s Institute bred mice that are genetically predisposed to developing the pathological changes of Alzheimer’s diseases in their brains.

They then kept the mice in one of four housing environments — high social activity, high physical activity, high cognitive activity, or a single housing control environment and watched them from young adulthood through old age.

When the researchers tested the mice in a battery of memory tasks in old age, only the mice given a lifelong high level of cognitive activity were protected against memory impairment. In fact, these “high cognitive activity” mice performed as well as normal mice that do not develop Alzheimer’s disease. However the Alzheimer’s mice raised in one of the other three environments performed poorly in multiple memory tasks.

Not only was memory protected in Alzheimer’s mice by a high level of cognitive activity, but also brain levels of the abnormal protein beta-amyloid were substantially reduced. This protein, thought to be key for Alzheimer’s development, remained at soaring levels in the brains of Alzheimer’s mice raised in social or physical activity environments. Moreover, the researchers found that only the Alzheimer’s mice raised with high cognitive activity had an increase in connections between brain cells. Alzheimer’s mice raised in one of the other three housing environments had much fewer connections between their brain cells.

The new study is published in the Neurobiology of Learning and Memory Journal.

The lead researcher is Gary Arendash, and he had this to say:

“Our results call into question the earlier human studies suggesting social or physical activity provides protection against Alzheimer’s. Alzheimer’s begins in the brain several decades before any symptoms´ show up. That means adults in their forties and fifties need to make lifestyle choices now to decrease their risk of getting Alzheimer’s disease later.”

This is all correct, but there is still an important question: can we really extrapolate from mice to humans? Mice are social creatures, but not to the same extent as humans beings. The lion’s share of the human brain is dedicated to social activities, so you would expect that social activities will be particularly important in the maintenance of the human brain.