Tuesday 16 May 2017

Insulin resistance bad for the brain

New research published in the Journal of Alzheimer's Disease reveals that insulin resistance is not only bad for the body, but also for the brain. The study involved five hundred people, who were monitored for more than twenty years.


In response to persistent glucose loading, the pancreas has to produce increasing amounts of insulin in order to still be able to store glucose. Over time, this cause the cells in the body to become insulin resistant, as a result which the surplus glucose accumulates in the circulation. Ultimately, this results in (pre)diabetes and other health problems. New research has revealed that these problems include cognitive decline.


Long-term, large-scale study

For more than 20 years, a group of 500 patients with existing cardiovascular disease were monitored. At the start of the study, the basal insulin resistance was measured with the HOMA index (Homeostatic Model Assessment), which is based on the fasting blood glucose and fasting insulin levels.


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Cognitive functions are measured using a test pack, taken on a computer. Information was gathered from the participants about the memory, executive functions, visual-spatial information processing and attention. Fifteen years later, the same test was repeated, as well as five years after that.


Accelerated cognitive decline

It was found that the 25 percent who obtained the highest score on the HOMA index at the end of the study, had poorer cognitive performance and demonstrated an accelerated cognitive decline in comparison to the other participants. Even after correction for any distorting variables, this result held good.


Insulin-resistant people mainly demonstrated a decline in executive functions and the memory, irrespective of whether or not they had diabetes. According to the researchers, the effect was partly caused by the additional weight gained and the lack of exercise.


Adapting the lifestyle does work

The researchers said: "The results can help us to identify people at an early stage who have an increased risk of cognitive decline and who will potentially develop dementia later in life. More exercise, a healthy diet and keeping the weight down can help to prevent insulin resistance and can therefore also protect the brain.”


The researchers are currently studying the mechanism of action behind insulin resistance and cognitive decline. The results of this study will be published in the future.



Miri Lutski et al, Insulin Resistance and Future Cognitive Performance and Cognitive Decline in Elderly Patients with Cardiovascular Disease, Journal of Alzheimer's Disease (2017).