The fact that obesity increases the risk of cardiovascular disease and some cancers is well known. But a new Iowa State University study adds to the growing evidence that memory loss should also be a top concern.
The study, published in the Journal of the American Medical Association ( JAMA ) Neurology, found a strong association between insulin resistance and memory function decline, increasing the risk for Alzheimer’s disease.
Insulin resistance is common in people who are obese, pre-diabetic or have type 2 diabetes.
Researchers have examined brain scans in 150 late middle-aged adults, who were at risk for Alzheimer’s disease, but showed no sign of memory loss.
The scans detected if people with higher levels of insulin resistance used less blood glucose in areas of the brain most susceptible to Alzheimer’s. When that happens, the brain has less energy to relay information and function.
Over the course of the Alzheimer’s disease there is a progressive decrease in the amount of blood glucose used in certain brain regions.
The work focused on the medial temporal lobe, specifically the hippocampus, a critical region of the brain for learning new things and sending information to long-term memory. It is also one of the areas of the brain that first show massive atrophy or shrinkage due to Alzheimer’s disease.
This is the first study to look at insulin resistance in late middle-aged people ( average age was 60 ), identify a pattern of decreased blood sugar use related to Alzheimer’s and link that to memory decline.
Participants were recruited through the University of Wisconsin-Madison and Wisconsin Registry for Alzheimer’s Prevention study, an ongoing study that examines genetic, biological and lifestyle factors that contribute to dementia.
The link between insulin resistance and Alzheimer’s disease is important for prevention, but the risk is much more immediate. Problems regulating blood glucose may impact cognitive function at any age.
Testing for insulin resistance in obese patients and taking corrective action, through improved nutrition and moderate exercise, is a crucial first step.
For Alzheimer’s, it’s not just people with type 2 diabetes. Even people with mild or moderate insulin resistance who don’t have type 2 diabetes might have an increased risk for Alzheimer’s disease. ( Xagena )
Source: Iowa State University, 2015