When it comes to many things, we already know that too much of a good thing can be a bad thing. Well, now researchers are giving us another reason to beware of a poor diet. A new study says insulin resistance, often linked to weight gain and obesity, could be linked to cognitive decline and Alzheimer's.
Researchers looked at 150 middle-aged people with an average age of 60, who were at risk for Alzheimer's, but did not show memory loss at the start of the study. Brain scans revealed that greater insulin resistance was linked to less sugar in key parts of the brain, often affected by Alzheimer's.
Insulin is the hormone that helps your body use sugar from the foods you eat, and either converts it into energy or stores it away. Insulin resistance is when your body's response to a regular level of the hormone is reduced, creating a need for more insulin.
“If you don’t have as much fuel, you’re not going to be as adept at remembering something or doing something,” the study's lead author Auriel Willette, of Iowa State University, said in a statement. “This is important with Alzheimer’s disease, because over the course of the disease there is a progressive decrease in the amount of blood sugar used in certain brain regions. Those regions end up using less and less.”
When this happens, the study's authors believe, certain parts of the brain can't carry out complex processes, like forming memories.
Insulin resistance often precedes diabetes and can be due to genetic factors, but it often occurs along with obesity, weight gain, stress and inactivity.
Your diet plays a role because sugary foods can spike your blood glucose levels, kicking your body's insulin response into high gear. Too many such spikes can lead to insulin resistance.
The study, published in JAMA Neurology, is in line with other studies which have shown the effects of a poor diet on brain function. One study published last month said a high-sugar, high-fat diet can disturb your brain's cognitive flexibility, making it difficult to switch between one thought concept to another. And a 2012 study said a high sugar diet can, over time, change the way your brain thinks (yikes!), altering your ability to learn and remember those things.
As for the current study, results showed poor sugar metabolism in the brain had immediate effects too, such as lowering memory scores.
So what can you do?
Willette says the main takeaway is for obese people to get tested for insulin resistance. As for everyone else, it serves as another reminder to watch your diet and get moving. "You don’t need to do intense gym workouts,” he told Yahoo! Health. He suggests getting at least 30 minutes of exercise, three times a week. “The more our muscles work, the more they sop up excess blood sugar all the time and prevent insulin resistance.”
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