Couch Potatoes Risk Insulin Resistance - and a Weakened Mind

When we don’t respond normally to insulin, our executive cognitive function and memory decline faster, Tel Aviv scientists report, urging you to exercise.

Illustrative: A man naps on a couch after eating pizza.
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Insulin resistance may cause the executive and cognitive functions of the brains to deteriorate faster, scientists researching Alzheimer’s Disease have shown.

While it remains to be elucidated how insulin resistance diminishes the functions of our minds, what’s certain is that the problem isn’t diabetes. According to research conducted at Tel Aviv University, cognitive decline in executive function and memory affected both diabetics and non-diabetics with insulin resistance.

A report on the study, which was jointly led by Prof. David Tanne and Prof. Uri Goldbourt and conducted by Dr. Miri Lutski, all of TAU’s Sackler School of Medicine, was published in the Journal of Alzheimer’s Disease.

“This study lends support for more research to test the cognitive benefits of interventions such as exercise, diet and medications that improve insulin resistance in order to prevent dementia,” says Tanne.

Our body normally produces the hormone insulin after we eat carbohydrates. The carbohydrates break down into simple sugars, which in turn cause the concentration of sugar in our blood to rise. That causes the body to release insulin from the pancreas into the bloodstream.

Among other things, insulin regulates our blood sugar level, “routing” surplus sugar molecules for storage as fat.

Insulin resistance is a pathological condition which prevents us from responding properly to insulin. Our muscle, fat and liver cells have difficulty absorbing glucose, which has two unfortunate results. One: To get glucose into the cells at all, the body requires higher levels of insulin. Two: That extra glucose builds up in the bloodstream.

The causes of insulin resistance may be purely pathological – genetic in origin, for instance – or stem from an idle lifestyle combined with being overweight. Doctors warn that insulin resistance often precedes the development of Type 2 diabetes.

Intriguingly, the findings linking insulin resistance to accelerated cognitive deterioration provides further support for the Brain Health Food Guide just published by Canada’s Rotman Research Institute.

Based on a huge amount of empirical data, the guide counsels eating a healthy diet heavy on legumes, fish, fresh fruit and vegetables and berries in order to preserve memory function after age 50. One of its authors, Dr. Carol Greenwood, pointed out, “There is general consensus that diets and lifestyles that lead to the development of insulin resistance and other chronic disorders, e.g. hypertension, contribute to poor cognitive retention and increased dementia risk.”

In short, doctors should keep a beady eye out for patients exhibiting insulin resistance, and not only because of the risk of diabetes. “We know that insulin resistance can be prevented and treated by lifestyle changes and certain insulin-sensitizing drugs,” says Tanne. “Exercising, maintaining a balanced and healthy diet and watching your weight will help you prevent insulin resistance and, as a result, protect your brain as you get older.”

And eating the Canadian diet, which is strikingly similar to the Mediterranean diet – it couldn’t hurt.

The conclusions of the insulin resistance study were based on studying a group of nearly 500 patients with existing cardiovascular disease for more than two decades, explain the scientists. Cognitive functions were assessed through computerized tests checking memory, executive function, visual spatial processing and attention. Follow-up assessments were conducted 15 years after the start of the study, and again five years after that.

The study found that individuals who suffer from the worst baseline insulin resistance had higher risk of poor cognitive performance and accelerated cognitive decline compared to all the others.