Data collected through EEG and with eye electrodes allowed researchers to measure brain activity and startle response. (Credit: Christopher Gannon/Iowa State U.)

diabetes

Brain scans show diabetics more likely to focus on negative

People with Type 2 diabetes and prediabetes are more likely to focus on and have a strong emotional response to threats and negative things, which affects quality of life and increases risk for depression, according to new research.

The study, which appears in Psychosomatic Medicine, suggests those negative feelings of sadness, anger, and anxiety—which can be a daily occurrence for people with diabetes or prediabetes—may stem from problems regulating blood sugar levels that influence emotional response in the brain.

Researchers analyzed data on startle response, brain activity, cortisol levels, and cognitive assessment. Data came from Midlife in the US (MIDUS), a national study of health and well-being.

Gauging the startle response allowed researchers to measure central nervous system activity using tiny electrodes placed below the eye, says Auriel Willette, assistant professor of food science and human nutrition at Iowa State University.

Study participants viewed a series of negative, positive, and neutral images intended to elicit an emotional response. The electrodes captured the rate of flinch or startle, a contraction we cannot control, associated with each image.

“People with higher levels of insulin resistance were more startled by negative pictures. By extension, they may be more reactive to negative things in life,” Willette says. “It is one piece of evidence to suggest that these metabolic problems are related to issues with how we perceive and deal with things that stress all of us out.”

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The evidence is even more compelling when combined with the results of EEG tests recording activity when the brain is at rest, researchers say.

Participants with prediabetes and Type 2 diabetes had more activity on the right side of the brain, which is associated with depression and negative emotions. If someone is predisposed to focusing on negative things, it may become a barrier for losing weight and reversing health issues, says lead author Tovah Wolf, a graduate student working with Willette.

People with prediabetes and diabetes also recorded lower cortisol levels—a potential indicator of chronic stress—and cognitive test scores, providing additional support for the findings.

“For people with blood sugar problems, being more stressed and reactive can cause blood sugar to spike. If people with prediabetes and diabetes are trying to reverse or treat the disease, stressful events may hinder their goals,” Wolf says. “Frequent negative reactions to stressful events can lead to a lower quality of life and create a vicious cycle that makes it difficult to be healthy.”

Willette can relate. He struggled with weight, at one time weighing 260 pounds, which affected his day-to-day quality of life. The risk of cardiovascular disease and other chronic illnesses related to obesity is well known, but many people may not recognize how fluctuations in blood sugar can take a toll on them every day, he says.

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Additional work is needed to determine if the link between insulin resistance and emotional response is causal, and explore options for potential interventions. Researchers from the University of Wisconsin-Madison contributed to the research.

Source: Iowa State University

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