Insulin sensitivity may explain link between obesity, memory problems

Oct 19, 2010

Because of impairments in their insulin sensitivity, obese individuals demonstrate different brain responses than their normal-weight peers while completing a challenging cognitive task, according to new research by psychologists at The University of Texas at Austin.

The results provide further evidence that a healthy lifestyle at midlife could lead to a higher quality of life later on, especially as new drugs and treatments allow people to live longer.

"The good thing about is that it's very modifiable through diet and exercise," says psychology graduate student Mitzi Gonzales, who co-authored the paper published in the journal Obesity with Assistant Professor Andreana Haley and other colleagues.

To better understand why midlife obesity is linked to higher risk of cognitive decline and dementia in old age, the researchers had middle-aged adults between 40 and 60 years of age complete a challenging cognitive task while undergoing functional (fMRI).

While obese, overweight and normal-weight participants performed equally well on the task, obese individuals displayed lower functional brain response in one brain region, the inferior parietal lobe.

Obese participants also had lower insulin sensitivity than their normal weight and overweight peers, meaning that their bodies break down glucose less efficiently. Poor insulin sensitivity may ultimately lead to diabetes mellitus if the pancreas is unable to secrete enough insulin to compensate for reduced glucose use.

The study shows that impaired insulin sensitivity, which generally accompanies obesity, may serve as a mediator between midlife obesity and cognitive decline later on. Researchers chose to examine insulin sensitivity because insulin helps regulate people's metabolism and also affects cognitive functions.

The study exemplifies the aim of Haley's lab, which is to use neuroimaging in middle-aged individuals to provide early identification of risk for later in life.

"Generally, very few people study the middle-aged segment of the population, but that's when many chronic diseases are first identified and neurodegenerative processes are triggered," says Haley. "We found that while behavioral performance of obese middle-aged individuals may be the same — they can complete the same cognitive tasks as normal weight individuals — their brain is already doing something different to produce that outcome."

Haley and Gonzales are planning a follow up study to determine if a 12-week exercise intervention can reverse the observed differences in brain response.

Explore further: Better living through mitochondrial derived vesicles

add to favorites email to friend print save as pdf

Related Stories

Does being overweight in old age cause memory problems?

Sep 19, 2007

While obesity has been shown to contribute to high blood pressure, heart disease and diabetes, being overweight in old age does not lead to memory problems, according to a study published September 19, 2007, in the online ...

How does insulin influence resistin?

Jan 16, 2008

Obesity is a worldwide health problem directly linked to several diseases such as hypertension and type 2 diabetes. Resistin is a cysteine-rich hormone mainly secreted by adipose tissues and may form a biochemical link between ...

New blood test might offer early warning of deep belly fat

Jul 10, 2007

Measuring levels of a chemical found in blood offers the best indicator yet of the amount of fat surrounding abdominal organs, according to a new study of lean and obese individuals reported in the July issue of Cell Metabolism, a publ ...

Recommended for you

Student seeks to improve pneumonia vaccines

1 hour ago

Almost a million Americans fall ill with pneumonia each year. Nearly half of these cases require hospitalization, and 5-7 percent are fatal. Current vaccines provide protection against some strains of the ...

Seabed solution for cold sores

3 hours ago

The blue blood of abalone, a seabed delicacy could be used to combat common cold sores and related herpes virus following breakthrough research at the University of Sydney.

Better living through mitochondrial derived vesicles

23 hours ago

(Medical Xpress)—As principal transformers of bacteria, organelles, synapses, and cells, vesicles might be said to be the stuff of life. One need look no further than the rapid rise to prominence of The ...

Zebrafish help to unravel Alzheimer's disease

Aug 19, 2014

New fundamental knowledge about the regulation of stem cells in the nerve tissue of zebrafish embryos results in surprising insights into neurodegenerative disease processes in the human brain. A new study by scientists at ...

Engineering new bone growth

Aug 19, 2014

MIT chemical engineers have devised a new implantable tissue scaffold coated with bone growth factors that are released slowly over a few weeks. When applied to bone injuries or defects, this coated scaffold ...

User comments : 0