Middle Age Spread Can Cause Dementia with Lack of Exercise Leading to ‘Rapid Mental Decline’ According to Study

Resistance to the hormone insulin sees the body fails to burn sugar and instead store it as fat – which is linked to Type 2 diabetes and brain disease.

Shirley Cramer, chief executive of the Royal Society of Public Health, is campaigning to change food labels, which she says could help reduce obesity

Being overweight can increase the risk of developing dementia in later life, according to research.A study found patients with insulin resistance, caused partly by obesity and lack of exercise, had more rapid mental decline. Resistance to the hormone is where the body fails to burn sugar and stores it as fat, and is linked to Type 2 diabetes.

The University of Tel Aviv in Israel tested insulin levels and cognitive function in 500 people. Follow-up tests 15 and 20 years later showed those in the top 25% for insulin inefficiency were more likely to have accelerated cognitive decline. Prof David Tanne said: “Watching your weight will help… protect your brain as you get older.”  The brain is especially vulnerable to the effects of insulin resistance, which triggers diabetes and is partly caused by obesity and lack of exercise.

This is according to a study of almost 500 patients followed for more than two decades found those in whom the hormone became inefficient suffered rapid mental decline.  Both their executive function, which controls learning and problem solving, and memory began to fail.  The findings add to evidence linking type 2 diabetes – the form linked to an unhealthy lifestyle – and led to an increased risk of dementia.  The metabolic condition happens when insulin becomes ineffective, meaning sugar is stored as fat instead of being burned by cells.  Professor Tanne, of the University of Tel Aviv, said beating the curse of middle age spread could help combat the dementia epidemic.

He said: “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.”    Earlier Swedish research involving about 8,500 Swedish twins found those who put on weight in middle age were almost twice as likely to develop dementia in later life.

Prof Tanne said: “These are exciting findings because they may help to identify a group of individuals at increased risk of cognitive decline and dementia in older age.  “We know that insulin resistance can be prevented and treated by lifestyle changes and certain insulin sensitizing drugs.

“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.”   Insulin resistance is a condition in which cells fail to respond normally to the hormone.  This prevents muscle, fat and the liver from absorbing glucose easily. As a result, the body requires higher levels of insulin to usher the sugar into its cells.  Without sufficient insulin, excess glucose builds up in the bloodstream leading to pre-diabetes, diabetes and other serious health disorders.  In the study published in the Journal of Alzheimer’s Disease participants were measured for insulin resistance at the start using a tool called HOMA (homeostasis model assessment.

This is calculated using fasting blood glucose and fasting insulin levels. Cognitive functions were also scored with a computerised battery of tests that examined memory, executive function, visual spatial processing and attention.  When the volunteers were followed up 15 years later, and again five years after that, the connection between insulin resistance and grey matter loss was identified.  Those who were in the top quarter of the HOMA index were more likely to perform badly in the tests and have accelerated cognitive decline compared to all the others.  All the participants had existing cardiovascular disease at the outset but the researchers said taking this into account, and other factors that may have skewed the findings, did not diminish the association.

In 2009 a US review of ten international studies involving more than 37,000 people found obese people had an increased risk of all types of dementia.  Experts believe hardening of the arteries and high blood pressure may play a role.  James Pickett, Head of Research, at Alzheimer’s Society, said: “There is strong evidence that poorly-managed diabetes can increase your risk of dementia.  “This research highlights that insulin resistance – which is related to diabetes – could have a negative impact on a person’s memory or thinking abilities.

“The study also adds to existing evidence that keeping our hearts and brains healthy as we age by eating well, exercising and not smoking are the best things we can do to reduce our risk of memory problems in later life.”

The study of almost 500 people was published in the Journal of Alzheimer’s Disease.



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