Your Aging Brain on Insulin

Insulin resistance tied to brain function in seniors

(RxWiki News) As you grow older, you may find your memory is not as good as it used to be. Seniors with diabetes may have even more problems with their brain health.

Elderly people with lower insulin sensitivity (a hallmark of type 2 diabetes) may have a smaller brain size and decreased language skills.

"Exercise to protect your brain health as you age."

In a past study, Christian Benedict of Uppsala University in Sweden showed that the hormone insulin plays a role in human memory. When the hormone reaches the brain, it improves memory function.

Insulin is a hormone that helps the body process sugar, or glucose, to use for energy. A person with a reduced insulin sensitivity either has diabetes or is at risk of diabetes. As people age, insulin's ability to metabolize sugar gets worse, putting elderly people at greater risk for diabetes.

With this information and his previous finding in mind, Benedict thought that insulin sensitivity may affect the rate of cognitive aging in elderly people. That is, insulin may play a role in the deterioration of the brain as people grow older.

Benedict and his colleagues wanted to see if insulin sensitivity was linked to brain health.

For their study, the researchers measured the brain structure and language skills of 331 75-year-olds. The researchers tested language skills by asking participants to name as many animals as possible in one minute. This is a test of something called verbal fluency.

Using magnetic imaging technology (MRT), the researchers found that elderly people with high insulin sensitivity had larger brains and more grey matter in parts of the brain important for language skills, compared to those who were less sensitive to insulin.

In other words, those who had diabetes or who were at risk of diabetes had smaller brains and less grey matter in the language centers of their brain.

"We also observed that higher insulin sensitivity was associated with better scores on the language test," says Benedict.

"Our findings offer a possible explanation for why methods that improve insulin sensitivity, such as exercise, are promising strategies for counteracting cognitive agin late in life," he concludes.

The full results of the study are published in the journal Diabetes Care

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Review Date: 
February 1, 2012