Blood sugar control boosts brain health for type 2 diabetes patients

Controlling blood sugar levels improved the ability to clearly think, learn, and remember among people with type 2 diabetes who were overweight, according to a new study published in the Journal of Clinical Endocrinology and Metabolism. However, losing weight and increasing physical activity produced mixed results, especially in obese patients.

The paper examined about 1,100 participants in the Look Action for Health in Diabetes (AHEAD) study. One group of participants was invited to three sessions each year that focused on diet, physical activity, and social support. The other group changed their diet and physical activity through a program designed to help them lose more than 7 percent of their body weight in a year and maintain that weight loss. Cognitive tests for thinking, learning, and remembering were given to participants between eight and 13 years after they started the study, according to the paper.

The research team theorized that people with greater improvements in blood sugar levels, physical activity, and weight loss would have better cognitive test scores. This hypothesis proved partially true, the researchers said. Reducing blood sugar levels did improve test scores but losing more weight and exercising more did not always raise cognitive test scores, they said.

More weight loss was either better or worse depending on the mental skill involved, the researchers said. People who lost more weight improved their executive function skills, including short-term memory, planning, impulse control, attention, and the ability to switch between tasks. However, their verbal learning and overall memory declined. Increasing physical activity also generated more benefits for people who had overweight compared to those with obesity, the researchers said.

Finding a way to offset the health effects of type 2 diabetes is critically important, the researchers said in a statement. More than 25 percent of U.S. adults 65 or older have type 2 diabetes, according to the U.S. Centers for Disease Control and Prevention. The disease doubles the risk of cognitive impairment and dementia, including Alzheimer's disease, and greatly increases healthcare needs and costs, said the researchers.

"It's important to properly control your blood sugar to avoid the bad brain effects of your diabetes," said Owen Carmichael, PhD, lead author of the study and professor and director at the Biomedical Imaging at Pennington Biomedical Research Center, in a statement. "Don't think you can simply let yourself get all the way to the obese range, lose some of the weight, and everything in the brain is fine. The brain might have already turned a corner that it can't turn back from."